Patent Publication Number: US-2023150221-A1

Title: Systems and methods for manufacturing a portion of an article of footwear from a mold

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Pat. Application No. 63/279,436 filed Nov. 15, 2021, the entirety of which is incorporated by reference. 
    
    
     REFERENCE REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
    
    
     SEQUENCE LISTING 
     Not applicable. 
     BACKGROUND 
     1. Field of the Invention 
     The present disclosure relates generally to manufacturing a portion of an article of footwear from a mold. 
     2. Description of the Background 
     Many conventional shoes or articles of footwear generally comprise an upper and a sole attached to a lower end of the upper. Conventional shoes further include an internal space, e.g., a void or cavity, which is created by interior surfaces of the upper and sole, which receives a foot of a user before securing the shoe to the foot. The sole is attached to a lower surface of the upper and is positioned between the upper and the ground. As a result, the sole typically provides stability and cushioning to the user when the shoe is being worn and/or is in use. In some instances, the sole may include multiple components, such as an outsole, a midsole, and an insole. The outsole may provide traction to a bottom surface of the sole, and the midsole may be attached to a surface of the outsole. 
     Typically, at least a portion of the sole is formed from a mold, but conventional molding processes are limited by geometry of the formed sole. The soles formed from a mold in conventional footwear articles are accordingly limited to simplistic geometries that are capable of being produced with conventional molding processes. 
     SUMMARY 
     An article of footwear, as described herein, may have various configurations. The article of footwear may have an upper and a sole assembly connected to the upper. In some embodiments, the sole assembly may include a midsole that is formed by a molding process. The molding process may efficiently form and maintain complex features in a midsole, e.g., undercuts, overhangs, apertures, tunnels, channels, etc. 
     In some embodiments, a method for manufacturing a sole assembly of an article of footwear includes injecting a first material into a first mold forming a first component in the first mold, and injecting a second material into a second mold forming a second component in the second mold. The first component is formed from the first material and includes a first plurality of channel elements. The second component is formed from the second material and includes a second plurality of channel elements. Each of the first plurality of channel elements is aligned with a corresponding one of the second plurality of channel elements, and the first component is secured to the second component to form an initial sole assembly. 
     In some embodiments, a method for manufacturing a sole assembly of an article of footwear includes inserting a mold insert and a first set of slider pins into a first mold base, flowing a first material into the first mold base to form a first component, removing the first component from the first mold base and the mold insert and inserting the first component into a second mold, and flowing a second material into the second mold and around the first component to form a second component that is attached to the first component. The first component has a plurality of tubes that extend laterally across the first component. The mold insert arranges the plurality of tubes below an upper surface of the first component within the first mold base. The second mold includes a second set of slider pins each received within a corresponding one of the plurality of tubes. The first component and the second component form a sole assembly. 
     In some embodiments, an article of footwear include an upper and a sole assembly defining a heel region, a midfoot region, and a forefoot region. The sole assembly includes a first component having a plurality of tubes attached to an upper surface thereof, and a second component including a plurality of apertures. The plurality of tubes extend laterally along the first component and are spaced apart in a heel-toe direction along at least the heel region. Each of the plurality of apertures defines a shape that is complementary to a shape defined by a corresponding one of the plurality of tubes in the first component. Each of the plurality of tubes is arranged within a corresponding one of the plurality of apertures to mechanically couple the first component to the second component. 
     Other aspects of the articles of footwear or portions of the articles of footwear described herein, including features and advantages thereof, will become apparent to one of ordinary skill in the art upon examination of the figures and detailed description herein. Therefore, all such aspects of the articles of footwear are intended to be included in the detailed description and this summary. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of a footwear assembly including an article of footwear; 
         FIG.  2    is a left or lateral side view of an article of footwear in the form of a left shoe; 
         FIG.  3    is a right or medial side view of the article footwear of  FIG.  2   ; 
         FIG.  4    is a top view of the article of footwear of  FIG.  2   ; 
         FIG.  5    is a top plan view of the article of footwear of  FIG.  2   , with an upper removed and a user’s skeletal foot structure overlaid on the article of footwear; 
         FIG.  6    is a flowchart outlining the steps in a method for manufacturing a sole assembly for an article of footwear; 
         FIG.  7    is a bottom view of a sole assembly including an array of channels; 
         FIG.  8    is a top view of the sole assembly of  FIG.  7   ; 
         FIG.  9    is a medial side view of the sole assembly of  FIG.  7   ; 
         FIG.  10    is a perspective view of a first mold used to manufacture a first component/layer of the sole assembly of  FIG.  7   ; 
         FIG.  11    is an exploded view of a second mold used to manufacture a second component/layer of the sole assembly of  FIG.  7   ; 
         FIG.  12    is a bottom perspective view of a top plate of the second mold of  FIG.  11   ; 
         FIG.  13    is a bottom perspective view of middle plates of the second mold of  FIG.  11   ; 
         FIG.  14    is a top perspective view of a bottom plate of the second mold of  FIG.  11   ; 
         FIG.  15    is an exploded view of a sole assembly including a drop-in component; 
         FIG.  16    is a top perspective view of the sole assembly of  FIG.  15    with the drop-in component inserted into the sole assembly; 
         FIG.  17    is a flowchart outlining the steps in another method for manufacturing a sole assembly for an article of footwear; 
         FIG.  18    is a flowchart outlining the steps in another method for manufacturing a sole assembly for an article of footwear; 
         FIG.  19    is a lateral side view of a first component of a sole assembly including a plurality of tubes; 
         FIG.  20    is a top perspective view of the first component of  FIG.  19   ; 
         FIG.  21    is an enlarged view of a plurality of tubes of the first component of  FIG.  19   ; 
         FIG.  22    is a lateral side view of a second component of the sole assembly including a plurality of apertures; 
         FIG.  23    is a bottom perspective view of the second component of  FIG.  22   ; 
         FIG.  24    is a lateral side view of the first component of  FIG.  19    installed onto the second component of  FIG.  22    to form the sole assembly; 
         FIG.  25    is a side view of the first component of  FIG.  19    arranged within a first mold; 
         FIG.  26    is a side view of the second component of  FIG.  22    arranged within a second mold; 
         FIG.  27    is a side view of the first component of  FIG.  20    arranged within another first mold; 
         FIG.  28    is an exploded view of the first mold of  FIG.  27   ; 
         FIG.  29    is an exploded view of a mold insert of the first mold of  FIG.  27   ; 
         FIG.  30    is a side view of the first component of  FIG.  20    arranged within a second mold; 
         FIG.  31    is a cross-sectional view of the second mold and the first component of  FIG.  30    taken along line 31-31; and 
         FIG.  32    is a side view of the second mold of  FIG.  30    with a second plate installed onto a second mold base. 
     
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     The following discussion and accompanying figures disclose various embodiments or configurations of a shoe. Although embodiments are disclosed with reference to a sports shoe, such as a running shoe, tennis shoe, basketball shoe, etc., concepts associated with embodiments of the shoe may be applied to a wide range of footwear and footwear styles, including basketball shoes, cross-training shoes, football shoes, golf shoes, hiking shoes, hiking boots, ski and snowboard boots, soccer shoes and cleats, walking shoes, and track cleats, for example. Concepts of the shoe may also be applied to articles of footwear that are considered non-athletic, including dress shoes, sandals, loafers, slippers, and heels. In addition to footwear, particular concepts described herein may also be applied and incorporated in other types of articles, including apparel or other athletic equipment, such as helmets, padding or protective pads, shin guards, and gloves. Even further, particular concepts described herein may be incorporated in cushions, backpacks, suitcases, backpack straps, golf clubs, or other consumer or industrial products. Accordingly, concepts described herein may be utilized in a variety of products. 
     The term “about,” as used herein, refers to variation in the numerical quantity that may occur, for example, through typical measuring and manufacturing procedures used for articles of footwear or other articles of manufacture that may include embodiments of the disclosure herein; through inadvertent error in these procedures; through differences in the manufacture, source, or purity of the ingredients used to make the compositions or mixtures or carry out the methods; and the like. Throughout the disclosure, the terms “about” and “approximately” refer to a range of values ± 5% of the numeric value that the term precedes. 
     The present disclosure is directed to an article of footwear and/or specific components or portions of the article of footwear, such as a midsole, an outsole, or a sole assembly. The article of footwear may include an upper that is at least partially formed from a knitted component, a woven textile, a non-woven textile, leather, mesh, suede, and/or a combination of one or more of the aforementioned materials. The knitted component may be made by knitting of yarn, the woven textile by weaving of yarn, and the non-woven textile by manufacture of a unitary non-woven web. Knitted textiles include textiles formed by way of warp knitting, weft knitting, flat knitting, circular knitting, and/or other suitable knitting operations. The knit textile may have a plain knit structure, a mesh knit structure, and/or a rib knit structure, for example. Woven textiles include, but are not limited to, textiles formed by way of any of the numerous weave forms, such as plain weave, twill weave, satin weave, dobbin weave, jacquard weave, double weaves, and/or double cloth weaves, for example. Non-woven textiles include textiles made by air-laid and/or spun-laid methods, for example. The upper may comprise a variety of materials, such as a first yarn, a second yarn, and/or a third yarn, which may have varying properties or varying visual characteristics. 
       FIG.  1    depicts a footwear assembly  20  that includes a pair of shoes  22  that are wearable by a user. In some embodiments, the footwear assembly  20  may include a left shoe  24  and a right shoe  26 . The left shoe  24  and the right shoe  26  may be similar in all material aspects, except that the left shoe  24  and the right shoe  26  are sized and shaped to receive a left foot and a right foot of a user, respectively. For ease of disclosure, a single shoe or article of footwear  25  will be referenced to describe aspects of the disclosure. In some figures, the article of footwear  25  is depicted as a right shoe, and in some figures the article of footwear is depicted as a left shoe. The disclosure below with reference to the article of footwear  25  is applicable to both the left shoe  24  and the right shoe  26 . 
       FIGS.  2 - 5    depict an exemplary embodiment of the article of footwear  25  including an upper  28  and a sole assembly  30 . As will be further discussed herein, the upper  28  is attached to the sole assembly  30  and together define an interior cavity  32  (see  FIGS.  4  and  5   ) into which a foot of a user may be inserted. For reference, the article of footwear  25  defines a forefoot region  34 , a midfoot region  36 , and a heel region  38  (see  FIG.  5   ). The forefoot region  34  generally corresponds with portions of the article of footwear  25  that encase portions of the foot that include the toes, the ball of the foot, and joints connecting the metatarsals with the toes or phalanges. The midfoot region  36  is proximate and adjoining the forefoot region  34 , and generally corresponds with portions of the article of footwear  25  that encase the arch of a foot, along with the bridge of a foot. The heel region  38  is proximate and adjoining the midfoot region  36  and generally corresponds with portions of the article of footwear  25  that encase rear portions of the foot, including the heel or calcaneus bone, the ankle, and/or the Achilles tendon. This geometric definition for the bounds of the forefoot region  34 , the midfoot region  36 , and the heel region  38  also applies to other forefoot regions, midfoot regions, and heel regions described herein. 
     The article of footwear  25  defines a lateral side  42  (see  FIG.  2   ) and a medial side  44  (see  FIG.  3   ). When a user is wearing the shoes, the lateral side  42  corresponds with an outside-facing portion of the article of footwear  25  while the medial side  44  corresponds with an inside-facing portion of the article of footwear  25 . As such, the left shoe  24  and the right shoe  26  have opposing lateral sides  42  and medial sides  44 , such that the medial sides  44  are closest to one another when a user is wearing the shoes  22 , while the lateral sides  42  are defined as the sides that are farthest from one another while the shoes  22  are being worn. 
     The medial side  44  and the lateral side  42  adjoin one another along a longitudinal central plane or axis  46  of the article of footwear  25  (see  FIG.  5   ). As will be further discussed herein, the longitudinal central plane or axis  46  may demarcate a central, intermediate axis between the medial side  44  and the lateral side  42  of the article of footwear  25 . Put differently, the longitudinal plane or axis  46  may extend between a rear distal end  48  of the article of footwear  25  and a front distal end  50  of the article of footwear  25  and may continuously define a middle of an insole  52 , the sole assembly  30 , and/or the upper  28  of the article of footwear  25 , i.e., the longitudinal plane or axis  46  is a straight axis extending through the rear distal end  48  of the heel region  38  to the front distal end  50  of the forefoot region  34 . 
     The forefoot region  34  may generally correspond with portions of the article of footwear  25  that encase portions of a foot  54  that include the toes or phalanges  56 , the ball of the foot  54 , and one or more of the joints  60  that connect the metatarsals  62  of the foot  54  with the toes or phalanges  56  (see  FIG.  5   ). The midfoot region  36  is proximate and adjoins the forefoot region  34 . The midfoot region  36  generally corresponds with portions of the article of footwear  25  that encase an arch of a foot  54 , along with a bridge of the foot  54 . The heel region  38  is proximate to the midfoot region  36  and adjoins the midfoot region  36 . The heel region  38  generally corresponds with portions of the article of footwear  25  that encase rear portions of the foot  54 , including the heel or calcaneus bone  64 , the ankle (not shown), and/or the Achilles tendon (not shown). 
     The forefoot region  34 , the midfoot region  36 , the heel region  38 , the medial side  44 , and the lateral side  42  are intended to define boundaries or areas of the article of footwear  25 . To that end, the forefoot region  34 , the midfoot region  36 , the heel region  38 , the medial side  44 , and the lateral side  42  generally characterize sections of the article of footwear  25 . Certain aspects of the disclosure may refer to portions or elements that are coextensive with one or more of the forefoot region  34 , the midfoot region  36 , the heel region  38 , the medial side  44 , or the lateral side  42 . Further, both the upper  28  and the sole assembly  30  may be characterized as having portions within the forefoot region  34 , the midfoot region  36 , the heel region  38 , and/or along the medial side  44  and/or the lateral side  42 . Therefore, the upper  28  and the sole assembly  30 , and/or individual portions of the upper  28  and the sole assembly  30 , may include portions thereof that are disposed within the forefoot region  34 , the midfoot region  36 , the heel region  38 , and/or along the medial side  44  and/or the lateral side  42 . 
     The forefoot region  34  extends from the front distal end  50  to a widest portion  68  of the article of footwear  25 . The widest portion  68  is defined or measured along a first line  70  that is perpendicular with respect to the longitudinal axis  46  that extends from the front distal end  50  to the rear distal end  48 , which is opposite the front distal end  50 . The midfoot region  36  extends from the widest portion  68  to a thinnest portion  74  of the article of footwear  25 . The thinnest portion  74  of the article of footwear  25  is defined as the thinnest portion of the article of footwear  25  measured across a second line  76  that is perpendicular with respect to the longitudinal axis  46 . The heel region  38  extends from the thinnest portion  74  to the rear distal end  48  of the article of footwear  25 . 
     The medial side  44  begins at the front distal end  50  and bows outward along an inner side of the article of footwear  25  along the forefoot region  34  toward the midfoot region  36 . The medial side  44  reaches the first line  70 , at which point the medial side  44  bows inward, toward the central, longitudinal axis  46 . The medial side  44  extends from the first line  70 , i.e., the widest portion  68 , toward the second line  76 , i.e., the thinnest portion  74 , at which point the medial side  44  enters into the midfoot region  36 , i.e., upon crossing the first line  70 . Once reaching the second line  76 , the medial side  44  bows outward, away from the longitudinal, central axis  46 , at which point the medial side  44  extends into the heel region  38 , i.e., upon crossing the second line  76 . The medial side  44  then bows outward and then inward toward the rear distal end  48  and terminates at a point where the medial side  44  meets the longitudinal, center axis  46 . 
     The lateral side  42  begins at the front distal end  50  and bows outward along an outer side of the article of footwear  25  along the forefoot region  34  toward the midfoot region  36 . The lateral side  42  reaches the first line  70 , at which point the lateral side  42  bows inward, toward the longitudinal, central axis  46 . The lateral side  42  extends from the first line  70 , i.e., the widest portion  68 , toward the second line  76 , i.e., the thinnest portion  74 , at which point the lateral side  42  enters into the midfoot region  36 , i.e., upon crossing the first line  70 . Once reaching the second line  76 , the lateral side  42  bows outward, away from the longitudinal, central axis  46 , at which point the lateral side  42  extends into the heel region  38 , i.e., upon crossing the second line  76 . The lateral side  42  then bows outward and then inward toward the rear distal end  48  and terminates at a point where the lateral side  42  meets the longitudinal, center axis  46 . 
     It should be understood that numerous modifications may be apparent to those skilled in the art in view of the foregoing description, and individual components thereof, may be incorporated into numerous articles of footwear. Accordingly, aspects of the article of footwear  25  and components thereof, may be described with reference to general areas or portions of the article of footwear  25 , with an understanding the boundaries of the forefoot region  34 , the midfoot region  36 , the heel region  38 , the medial side  44 , and/or the lateral side  42  as described herein may vary between articles of footwear. 
     However, aspects of the article of footwear  25  and individual components thereof, may also be described with reference to exact areas or portions of the article of footwear  25  and the scope of the appended claims herein may incorporate the limitations associated with these boundaries of the forefoot region  34 , the midfoot region  36 , the heel region  38 , the medial side  44 , and/or the lateral side  42  discussed herein. 
     With continued reference to  FIGS.  2 - 5   , the sole assembly  30  is connected or secured to the upper  28  and extends between a foot of a user and the ground when the article of footwear  25  is worn by the user. The sole assembly  30  may also include one or more components, which may include an outsole, a midsole, a heel, a vamp, a stiffening member (e.g., a carbon plate) and/or an insole. For example, in some embodiments, a sole assembly may include an outsole that provides structural integrity to the sole assembly, along with providing traction for a user, a midsole that provides a cushioning system, and an insole that provides support for an arch of a user. 
     The sole assembly  30  may be characterized by an outsole or outsole region  78 , a midsole or a midsole region  80 , and the insole or insole region  52 . The outsole  78 , the midsole  80 , and the insole  52 , and/or any components thereof, may include portions within the forefoot region  34 , the midfoot region  36 , and/or the heel region  38 . Further, the outsole  78 , the midsole  80 , and the insole  52 , and/or any components thereof, may include portions on the lateral side  42  and/or the medial side  44 . 
     In other instances, the outsole  78  may be defined as a portion of the sole assembly  30  that at least partially contacts an exterior surface, e.g., the ground, when the article of footwear  25  is worn. The insole  52  may be defined as a portion of the sole assembly  30  that at least partially contacts a user’s foot when the article of footwear is worn. Finally, the midsole  80  may be defined as at least a portion of the sole assembly  30  that extends between and connects the outsole  78  with the insole  52 . In some embodiments, the outsole  78  may be fabricated from an injection molded thermoplastic material (e.g., thermoplastic polyurethane), a molded polyurethane material, or a rubber material. In some embodiments, the outsole  78  may define a shore A hardness between about  55  and about  75 . 
     As described herein, the sole assembly  30  may be connected or secured to the upper  28 . Many conventional footwear uppers are formed from multiple elements, e.g., textiles, polymer foam, polymer sheets, leather, and/or synthetic leather, which are joined through bonding or stitching at a seam. In some embodiments, the upper  28  of the articles of footwear  25  is formed from a knitted structure or knitted components. In various embodiments, a knitted component may incorporate various types of yarn that may provide different properties to an upper. For example, one area of the upper  28  may be formed from a first type of yarn that imparts a first set of properties, and another area of the upper  28  may be formed from a second type of yarn that imparts a second set of properties. Using this configuration, properties of the upper  28  may vary throughout the upper  28  by selecting specific yarns for different areas of the upper  28 . In some embodiments, the article of footwear  25  may include a first or mesh layer and a second or base layer. The base layer may include multiple layers, such as an outer surface  88  upon which a plurality of eyelets  90  may be provided, and an interior surface  92  that engages with a foot when a user puts on the article of footwear  25 . The mesh layer and the base layer may be connected at one or more locations along the article of footwear  25 . 
     With reference to the material(s) that comprise the upper  28 , the specific properties that a particular type of yarn will impart to an area of a knitted component may at least partially depend upon the materials that form the various filaments and fibers of the yarn. For example, cotton may provide a soft effect, biodegradability, or a natural aesthetic to a knitted material. Elastane and stretch polyester may each provide a knitted component with a desired elasticity and recovery. Rayon may provide a high luster and moisture absorbent material, wool may provide a material with an increased moisture absorbance, nylon may be a durable material that is abrasion-resistant, and polyester may provide a hydrophobic, durable material. 
     Other aspects of a knitted component may also be varied to affect the properties of the knitted component and provide desired attributes. For example, a yarn forming a knitted component may include monofilament yarn or multifilament yarn, or the yarn may include filaments that are each formed of two or more different materials. In addition, a knitted component may be formed using a particular knitting process to impart an area of a knitted component with particular properties. Accordingly, both the materials forming the yarn and other aspects of the yarn may be selected to impart a variety of properties to particular areas of the upper  28 . 
     In some embodiments, an elasticity of a knit structure may be measured based on comparing a width or length of the knit structure in a first, non-stretched state to a width or length of the knit structure in a second, stretched state after the knit structure has a force applied to the knit structure in a lateral direction. In further embodiments, the upper  28  may also include additional structural elements. For example, in some embodiments, a heel plate or cover (not shown) may be provided on the heel region  38  to provide added support to a heel of a user. In some instances, other elements, e.g., plastic material, logos, trademarks, etc., may also be applied and fixed to an exterior surface using glue or a thermoforming process. In some embodiments, the properties associated with the upper  28 , e.g., a stitch type, a yarn type, or characteristics associated with different stitch types or yarn types, such as elasticity, aesthetic appearance, thickness, air permeability, or scuff-resistance, may be varied. 
     In the illustrated embodiment, as shown at least in  FIGS.  2  and  3   , the upper  28  extends upwardly from the sole assembly  30  and defines the interior cavity  32  that receives and secures a foot of a user. The upper  28  may be defined by a foot region  84  and an ankle region  86 . In general, the foot region  84  extends upwardly from the sole assembly  30  and through the forefoot region  34 , the midfoot region  36 , and the heel region  38 . The ankle region  86  is primarily located in the heel region  38 ; however, in some embodiments, the ankle region  86  may partially extend into the midfoot region  36 . 
     The upper  28  extends along the lateral side  42  and the medial side  44  as shown in  FIG.  4   , and across the forefoot region  34 , the midfoot region  36 , and the heel region  38  as shown in  FIG.  5    to house and enclose a foot of a user. When fully assembled, the upper  28  also includes an interior surface  92  and an outer surface  88 , as shown in  FIG.  4   . The interior surface  92  faces inward and generally defines the interior cavity  32 , and the outer surface  88  of the upper  28  faces outward and generally defines an outer perimeter or boundary of the upper  28 . The interior surface  92  and the outer surface  88  may comprise portions of the base and/or mesh layers disclosed above. The upper  28  also includes an opening  94  that is at least partially located in the heel region  38  of the article of footwear  25 , that provides access to the interior cavity  32  and through which a foot may be inserted and removed. In some embodiments, the upper  28  may also include an instep area  96  that extends from the opening  94  in the heel region  38  over an area corresponding to an instep of a foot to an area adjacent the forefoot region  34 . The instep area  96  may comprise an area similar to where a tongue  98  of the present embodiment is disposed. In some embodiments, the upper  28  does not include the tongue  98 , i.e., the upper  28  is tongueless. 
     As further shown in  FIG.  4   , a lace  99  may be threaded through a plurality of eyelets  90 . The lace  99  may be manipulated by a user to allow the user to modify dimensions of the upper  28 , e.g., to tighten or loosen portions of the upper  28 , around a foot as desired by the user. In some embodiments, the article of footwear  25  may not be provided with a manually operated lace  99  and may instead include an automatic lacing system that is electronically operated. In some embodiments, an article of footwear may not include a lace, and dimensions of the upper can be modified through other mechanisms as, for example, through hook and loop fasteners. In some embodiments, an elasticity of the upper can allow the upper to conform to a shoe of a user, and an article of footwear need not include elements for modifying dimensions of the upper. As described herein, a sole assembly may provide cushioning to a user wearing an article of footwear. In general, sole assemblies are manufactured or formed using a mold and the finished components (e.g., outsole, midsole, etc.) are required to be demolded and removed from the mold prior to assembling into an article of footwear. The demolding requirement of the formed components significantly restricts the geometry of the sole assembly and the mold. For example, the inclusion of undercuts (i.e., an indentation or protrusion in the sole assembly that can prevent withdrawal of the sole assembly from a mold) is not possible with conventional molding processes. Further, apertures, openings, interconnected winding channels, or other recesses that are not formed in a demolding direction are prohibitively complex to produce with conventional molding technologies. 
       FIGS.  7 - 9    illustrate an embodiment of a sole assembly  200  according to one aspect of the present disclosure. In some embodiments, the sole assembly  200  may be formed using processes and techniques described herein (e.g., process  100  shown in  FIG.  6   ). In some embodiments, as shown in  FIG.  9   ., the sole assembly  200  may be formed from a first component  202  and a second component  204 . The first and second components  202 ,  204  can be respective layers of the sole assembly  200 , and, as used herein, the terms “layer” and “component” are used interchangeably. In the illustrated embodiment, the first component  202  includes an outsole  206  and a first portion  208  of a midsole  210 . In some embodiments, the first component  202  may include the first portion  208  of the midsole  210  and the outsole  206  may be attached to the sole assembly  200  after the sole assembly  200  is formed. In the illustrated embodiment, the second component  204  includes a second portion  212  of the midsole  210 . 
     In some embodiments, the first component  202  or a portion thereof may be fabricated from a thermoplastic material, e.g., thermoplastic polyurethane, ethylene-vinyl acetate, nylon, nylon polyamide, thermoplastic elastomer, thermoplastic polyamide, etc. In some embodiments, the second component  204  may be fabricated from a material that differs in at least one of color, density, hardness, and chemical composition from the first component  202 . For example, the first component  202  may be fabricated from a first material, e.g., one of thermoplastic polyurethane, ethylene-vinyl acetate, nylon, nylon polyamide, thermoplastic elastomer, thermoplastic polyamide, etc., and the second component  204  may be fabricated from a second material that is different than the first material, e.g., a different one of thermoplastic polyurethane, ethylene-vinyl acetate, nylon, nylon polyamide, thermoplastic elastomer, thermoplastic polyamide, etc., or a different color of the same chemical composition. 
     In the illustrated embodiment, the outsole  206  is attached to a bottom surface  214  of the midsole  210  and defines a generally wavy pattern. For example, the outsole  206  may include a plurality of rounded protrusions  216  and a plurality of recesses  218  formed between adjacent pairs of the plurality of rounded protrusions  216  to define a wave-like pattern along the outsole  206 . In the illustrated embodiment, the wave-like pattern extends along the outsole  206  in a heel-toe direction  220  from a heel region  222  through a midfoot region  224  and into a forefoot region  226 . In some embodiments, as shown in  FIG.  7   , an outer surface  228  of the outsole  206  may define a tread pattern. In the illustrated embodiment, the outer surface  228  defines an array of tread protrusions  230  extending from the outer surface  228 . In other embodiments, the outer surface  228  may define a different tread pattern, or may define a smooth, uninterrupted profile. 
     Referring now to  FIG.  8   , in some embodiments, the sole assembly  200  includes an upper surface  232  that is formed on the second component or layer  204 . In general, the upper surface  232  may receive an upper to form an article of footwear that includes the sole assembly  200 . In the illustrated embodiment, the upper surface  232  includes a plurality of grooves  234  extending laterally along the upper surface  232 . The grooves  234  are spaced from one another in the heel-toe direction  220 . In the illustrated embodiment, the grooves  234  are at least partially arranged within the midfoot region  224  and the forefoot region  226  (e.g., as shown in  FIG.  9   ), and the grooves  234  may provide increased flexibility to the sole assembly  200 . 
     With specific reference to  FIG.  9   , the sole assembly  200  includes a plurality of channels  236  that extend laterally through the sole assembly  200 . For example, each of the plurality of channels  236  may extend laterally through the midsole  210  between a lateral side  238  and a medial side  240  (not shown in  FIG.  9    but illustrated in  FIGS.  7  and  8   ). In the illustrated embodiment, the plurality of channels  236  define a generally cylindrical shape and extend along the sole assembly  200  in the heel-toe direction  220  from the heel region  222  to the forefoot region  226 . In the illustrated embodiment, the plurality of channels  236  defines an array of channels that includes channels that are spaced in both the heel-toe direction  220  and a sole-upper direction  242 . 
     In the illustrated embodiments, a portion of the plurality of channels  236  include end caps  244  that cover the ends of the respective channel. For example, a portion of the channels  236  may be open with apertures being arranged at both lateral ends thereof, and another portion of the channels  236  may be closed at the lateral ends thereof by the end caps  244 . Each of the channels  236  that is plugged by an end cap  244  may define a recess  246  at the lateral end of the channel  236  that is laterally recessed into the midsole  210 . 
     In general, at least a portion of the plurality of channels  236  may include channels that are formed at an intersection between the first component  202  and the second component  204 . For example, each of the plurality of channels  236  at this intersection may be formed by two partial channels, one partial channel being formed in the first component  202  and another partial channel being formed in the second component  204 . In the illustrated embodiment, the first component or layer  202  may include a first plurality of partial channels  248  extending laterally across the first component or layer  202 . Each of the first plurality of partial channels  248  may define approximately half of a respective one of the channels  236  formed at the intersection between the first component  202  and the second component or layer  204  (e.g., a lower half from the perspective of  FIG.  9   , with the dashed line extending through the channel illustrating the boundary of the first partial channel  248 ). Similarly, the second component  204  may include a second plurality of partial channels  250  extending laterally across the second component  20   4 . Each of the second plurality of partial channels  250  may define a remaining half (e.g., an approximate half) of a respective one of the channels  236  formed at the intersection between the first component  202  and the second component  204  (e.g., an upper half from the perspective of  FIG.  9   , with the dashed line extending through the channel illustrating the boundary of the second partial channel  250 ). In the illustrated embodiment, each of the first plurality of partial channels  248  aligns with a corresponding one of the second plurality of partial channels  250  to form a complete channel  236  that extends laterally across the sole assembly  200  (e.g., through the midsole  210 ). 
     In the illustrated embodiment, the first component or layer  202  engages or attaches to the second component or layer  204  in regions between each of the plurality of channels  236  formed at the intersection between the first component  202  and the second component  204 , where the engagement boundary is illustrated by the dash-dot-dash lines in  FIG.  9   . The first component or layer  202  is bonded to the second component or layer  204  in these engagement regions formed between the plurality of channels  236 . 
     The present disclosure provides systems and methods for forming or manufacturing a sole assembly (e.g., the sole assembly  200  shown in  FIGS.  7 - 9   ) with complex and customizable geometric features using a molding process that is not limited by design. For example, the systems and methods of the present disclosure provide a molding process that enables the formation of one or more channels that extend through the sole assembly to provide improved comfort and performance as compared to conventional sole assemblies and molding processes. 
       FIG.  6    illustrates an example process  100  for manufacturing a sole assembly of an article of footwear according to some embodiments of the present disclosure. The process  100  may initiate at block  102  by injecting a first material into a first mold (e.g., mold  300  illustrated in  FIG.  10   ) to form a first component of a sole assembly (e.g., the first component  20   2  of the sole assembly  200 ). The first material may include a thermoplastic material, e.g., thermoplastic polyurethane, ethylene-vinyl acetate, nylon, nylon polyamide, thermoplastic elastomer, thermoplastic polyamide, etc. In some embodiments, the first component may be an outsole of an article of footwear (e.g., the outsole  206  shown in  FIGS.  7  and  9   ). In some embodiments, the first component may be a first portion of a midsole of an article of footwear (e.g., a first portion  208  of the midsole  210  shown in  FIG.  9   ). In some embodiments, the first component may be an outsole and a first portion of a midsole formed as a unitary component (e.g., the first component  202  shown in  FIG.  9   ). 
     The first material may remain within the first mold until it solidifies into the first component (e.g., the first component  202  shown in  FIG.  9   ). In some embodiments, the first mold may include a plurality of first protrusions that extend laterally across the first mold. In these embodiments, each of the plurality of first protrusions is configured to form a partial channel that extends laterally across the first component. The plurality of partial channels may each define a shape that is about half of a completed, enclosed channel. For example, each of the plurality of partial channels may define about half of a circular-, rectangular-, square-, triangular-, oval-, or hexagonally-shaped channel, or any other polygon-shaped channel. In some embodiments, the plurality of partial channels may be spaced along the first component in a heel-toe direction from a heel region to a forefoot region. In some embodiments, the plurality of partial channels may be spaced along the first component in a heel-toe direction from a heel region to a toe region. In some embodiments, the plurality of partial channels may be spaced along the first component in a heel-toe direction within a heel region. 
     In this regard,  FIG.  10    illustrates one embodiment of a first mold  300  that may be used (e.g., at block  102  of process  100 ) to form a first component (e.g., the first component  202  shown in  FIG.  9   ). As described with respect to the process  100 , in some embodiments, a partial channel may be formed in a first component via a protrusion in the first mold  300 . In some embodiments, the first mold  300  may be used to form a first component or layer according to the process  100 . In the illustrated embodiment, the first mold  300  includes a first mold insert  302  and a first mold base  304 . The first mold insert  302  is configured to be inserted into the first mold base  304  to form a cavity between the first mold insert  302  and the first mold base  304  within which the first material may be injected to form a first component or layer (e.g., first component  202  illustrated in  FIGS.  7 - 9   ). 
     In the illustrated embodiment, the first mold insert  302  includes a first insert surface  306  that protrudes outwardly from an upper surface  308  of the first mold insert  302 . The first insert surface  306  includes a plurality of first insert protrusions  310  and a plurality of first insert recesses  312  formed between adjacent pairs of the plurality of first insert protrusions  310 . The first mold base  304  may include a first base surface  314  that is recessed relative to an upper surface  316  of the first mold base  304 . Similar to the first mold insert  302 , the first base surface  314  includes a plurality of first base protrusions  318  and a plurality of first base recesses  320  formed between adjacent pairs of the plurality of first base protrusions  318 . In the illustrated embodiment, the first base surface  314  also includes a plurality of tread recesses  322 , which form a tread pattern on the first component (e.g., the tread protrusions  230  in the first component  202  shown in  FIG.  7   ). 
     To form the first component  202  (shown in  FIGS.  7 - 9   ), a first material may be injected into the first mold base  304  and the first mold insert  302  may be inserted into the first mold base  304 , so that the first insert surface  306  is received within the cavity formed by the recessed nature of the first base surface  314 . With the first mold insert  302  pressed into the first mold base  304 , the first insert surface  306  may oppose the first base surface  314  with a gap or cavity arranged therebetween that defines the shape and size of the first component  202 . In this pressed configuration, each of the plurality of first insert protrusions  310  may oppose a corresponding one of the first base recesses  320 , and each of the plurality of first insert recesses  312  may oppose a corresponding one of the plurality of first base protrusions  318 . The engagement of the first material with the first base recesses  320  and first base protrusions  318  can produce the plurality of rounded protrusions  216  and the plurality of recesses  218  in the first component  202 . Similarly, the plurality of first insert protrusions  310  and the plurality of first insert recesses  312  can engage the first material to produce the first plurality of partial channels  248  in the first component or layer  202  (as shown in  FIG.  9   ). 
     Referring back to  FIG.  6   , once the first component is formed in the first mold, the first component may then be removed from the first mold and inserted into a second mold at block  104  (e.g., the second mold  330  illustrated in  FIGS.  11 - 14   ). The second mold may include a plurality of second pins extending laterally across an interior of the second mold (e.g., pins  344  shown in  FIG.  13   ). For example, the plurality of second pins may be slidably arranged within the second mold at block  106 , so that the plurality of pins extend through the interior of the second mold and each of the plurality of partial channels in the first component receives a corresponding one of the plurality of second pins in the second mold. 
     With the first component arranged within the second mold, and the plurality of second pins extending through and being received by the plurality of partial channels, the first component may be overmolded with a second material to form a second component or a second layer that, together with the first component or the first layer, form an initial sole assembly at block  108 . In some embodiments, the overmolding at block  108  may comprise injecting a second material into the second mold that flows over the first component and around the plurality of second pins. In some embodiments, the second material may be different than the first material. For example, the second material may differ in at least one of color, density, hardness, and chemical composition when compared to the first material. In some embodiments, the second material may be the same as the first material. The second material may include a thermoplastic material, e.g., thermoplastic polyurethane, ethylene-vinyl acetate, nylon, nylon polyamide, thermoplastic elastomer, thermoplastic polyamide, etc. In some embodiments, the second component or layer includes a midsole. In some embodiments, the second component or layer includes a second portion of a midsole. 
     The first component or layer may be bonded to the second component or the second layer in regions between the completed channels formed in the initial sole assembly. Specifically, in regions between the plurality of second pins, the second material may engage and bond to the first material to attach the first component or layer to the second component or layer. 
     The plurality of second pins within the second mold form a plurality of channels extending laterally through the initial sole assembly. For example, the plurality of channels may extend through the initial mold assembly from a lateral side to a medial side. Each of the plurality of channels may be formed by a corresponding one of the plurality of partial channels in the first component and a corresponding one of a second plurality of partial channels formed in the second component or the second layer during the overmolding process. Each of a first plurality of partial channels in the first component or first layer may align with a corresponding one of the second plurality of partial channels formed in the second component or the second layer to form a plurality of completed channels extending through the initial sole assembly. 
     In some embodiments, the plurality of channels defines an array of channels that extend along the initial sole assembly in a heel-toe direction from a heel region to a forefoot region. In some embodiments, the array of channels includes channels that are spaced in a sole-upper direction. In some embodiments, the array of channels includes upper channels that extend through and are arranged on an upper surface of the initial sole assembly. 
       FIGS.  11 - 14    illustrate one embodiment of a second mold  330  that may be used at blocks  104 ,  106 , and  108  to form a second component (e.g., the second component  204  shown in  FIGS.  7 - 9   ) and overmold the first component (e.g., the first component  202  shown in  FIGS.  7 - 9   ) to form the initial sole assembly. In the illustrated embodiment, the second mold  330  includes a top plate  332 , a pair of middle plates  334 , and a bottom plate  336 . The top plate  332  may be inserted onto a top side of the pair of middle plates  334 , and the bottom plate  336  may be inserted onto a bottom side of the middle plates  334 , which defines a cavity within the volume enclosed by the top plate  332 , the middle plates  334 , and the bottom plate  336 . The cavity defined by this enclosed volume may receive a first component or layer and the second component or layer may be overmolded onto the first component or layer by injecting a material into the remaining volume defined by the cavity. 
     With specific reference to  FIG.  12   , the top plate  332  includes a top mold surface  338  that protrudes outwardly from an upper surface  340  of the top plate  332 . The top mold surface  338  includes a plurality of ribs  342  that protrude outwardly from the top mold surface and extend laterally across the top mold surface  338 . The plurality of ribs  342  form the plurality of grooves  234  on the upper surface  232  of the initial sole assembly  200 , as shown in  FIG.  8   . 
     Turning to  FIG.  13   , each of the middle plates  334  include a plurality of pins (e.g., slider pins  344 ) that extend laterally outwardly from a respective side surface  345  of each of the middle plates  334 . The pins  344  extend laterally outwardly from the side surfaces  345  by a distance that ensures that when the second mold  330  is assembled, the distal ends of the pins  344  of one of the middle plates  334  engage the distal ends of the pins of the other middle plate  334  to form an array of continuous pins that extend across the cavity defined by the second mold. In general, the location and size of the pins  344  determine a size and location of the plurality of channels  236  in the initial sole assembly, as shown in  FIG.  9   . A portion of the pins  344  are positioned to form the channels at the intersection between the first component and the second component. For example, the pins  344  can be arranges to be received within the each of the first plurality of partial channels  248  formed in the first component 202 , and to define the second plurality of partial channels  250  when the second material is overmolded to the first component  202  to form the second component. 
     In some embodiments, the second mold  330  may include a single middle plate  334 , rather than a pair of middle plates  334 . For example, if the first component only includes partial channels, e.g., not enclosed channels, then the second mold  330  may include a single middle plate  334 . If the pins  344  are required to be inserted through completed channels formed in the first component, then the second mold  330  may include a pair of middle plates  334  to enable each plate to be inserted through the channels in the first component, e.g., one in each end of the channels. In some embodiments, a sole assembly can have more than two components. For example, a second mold can have additional pairs of middle plates to overmold a third component onto a second component. With reference to  FIG.  14   , the bottom plate  336  includes a bottom mold surface  346  that protrudes outwardly from a lower surface  348  of the bottom plate  336 . The bottom mold surface  346  includes a plurality of bottom protrusions  350  and a plurality of bottom recesses  352  formed between adjacent pairs of the plurality of bottom protrusions  350 . This structure defined by the plurality of bottom protrusions  350  and the plurality of bottom recesses  352  formed in the bottom mold surface  346  is designed to conform to the structure of the first component or layer  202 . For example, the bottom mold surface  346  is configured to receive the first component or layer  202  to arrange the first component or layer  202  within the second mold  330 . In other embodiments, a bottom mold surface of a bottom plate can include other patterns to receive first components with different arrangements of protrusions and recesses. 
     The middle plates  334  may then be inserted onto the bottom plate  336  so that each of the first plurality of partial channels  248  in the first component or layer  202  receives a corresponding one of the plurality of pins  344  in the second mold  330 . The top plate  332  may then be inserted onto the middle plates  334  so that the top mold surface  338  opposes the bottom mold surface  346 . The volume enclosed between the bottom mold surface  346 , the top mold surface  338 , the side surfaces  345  of the middle plates  334 , and the first component or layer  202  defines a cavity within which the second material may be injected to for the initial sole assembly  200  by overmolding the second component or layer  204  to the first component or layer  202 . As the second component or layer  204  is overmolded to the first component or layer  202 , the second material injected into the cavity of the second mold  330  may flow around each of the pins  344 , which forms the plurality of channels  236  in the initial sole assembly  200 , including the second plurality of partial channels  250  that complement the first plurality of partial channels  248 . 
     Once the initial sole assembly  200  is formed (e.g., formed at blocks  104 ,  106 , and  108  of process  100  shown in  FIG.  6   ), the second mold  330  may be disassembled and the formed initial sole assembly  200  may be expanded and compressed according to the process  100  to form the final sole assembly. 
     In this regard, referring back to  FIG.  6   , the initial sole assembly may define an initial size (e.g., a volume) that is scaled down (e.g., smaller) relative to a final, production-intent size of a sole assembly. At block  110 , the initial sole assembly may be expanded from the initial size to an intermediate size to form an expanded sole assembly. For example, the initial sole assembly may be expanded via a supercritical foaming process by which the initial sole assembly is enclosed in a pressurized autoclave and supplied with pressurized gas (e.g., pressurized on the order of several thousand pounds per square inch). In some embodiments, the gas supplied can be one of nitrogen or carbon dioxide. In some embodiments, other gases can be used in a supercritical foaming process to expand a sole assembly. The pressurized gas within the autoclave may transmit (e.g., enter) into the initial sole assembly. Upon depressurization of the autoclave, a pressure differential between the high-pressure gas in the initial sole assembly and the depressurized autoclave may cause the initial sole assembly to expand from the initial size to the intermediate size. The array of channels in the expanded sole assembly can expand at block  110  to define a larger size than the array of channels in the initial sole assembly, thus providing reduced weight properties and improved cushioning properties to the expanded midsole. 
     In some embodiments, the initial sole assembly may be scaled down by a scale factor, or define a smaller volume relative to a final, production-intent size (e.g., volume) of a final sole assembly that may be manufactured with an article of footwear (e.g., the article of footwear 25). For example, the size (e.g., a volume) of the initial sole assembly may be about 70% smaller, about 65% smaller, about 60% smaller, about 55% smaller, about 50% smaller, about 45% smaller, about 40% smaller, about 35% smaller, or about 30% smaller than the final, production-intent size of the final sole assembly. In some embodiments, the size of the initial sole assembly may be between about 70% and about 30% smaller, between about 65% and about 35% smaller, or between about 60% and about 40% smaller than the final, production-intent size of the final sole assembly. In some embodiments, the initial size of the initial sole assembly may be between about 70% and about 60% smaller, between about 50% and about 40% smaller, or between about 30% and about 20% smaller than the final, production-intent size of the final sole assembly. 
     In some embodiments, the scale factors for the size of the initial sole assembly relative to the final sole assembly are uniform (e.g., dimensions of the initial sole assembly can be scaled down by the same scale factor about all coordinate axes defined by the sole assembly). In some embodiments, the scale factors described herein may vary or define a gradient across the sole assembly. For example, some portions of the initial sole assembly may be scaled down in volume relative to the final sole assembly more or less than other portions of the sole assembly. In some embodiments, the mass properties (e.g., density) of portions of the formed final sole assembly may determine the magnitude of the scale factor (e.g., may determine a magnitude of expansion of the final sole assembly relative to the initial sole assembly) relative to corresponding portions of the initial sole assembly. For example, portions of the initial sole assembly with greater densities or thicknesses can expand by a smaller scale factor relative to portions with lower thicknesses or densities. 
     In some embodiments, a gradient defined by the scale factor may correlate to a geometric characteristic of the final sole assembly (e.g., thickness, volume, or a geometric property defined along at least one coordinate axis), with areas that define a larger geometric characteristic being scaled down more than areas that define a smaller geometric characteristic, so that those areas are expanded more in the final sole assembly than in the initial sole assembly. In some embodiments, the scale factors described herein may scale down the initial sole assembly in one direction or along one coordinate axis defined by the midsole. For example, the initial sole assembly may be structurally supported by a mold base or frame to prevent expansion along two directions (e.g., along an x-axis and a z-axis, or along a plane that is parallel to a ground plane that an article of footwear rests upon while being worn by a user), and the size of the initial sole assembly may be approximately equal to the final size of the final sole assembly along these two directions. The initial sole assembly, with the scaled-down size in one direction, may then be expanded along the one direction that is allowed by the mold base or frame (e.g., a y-axis or the coordinate axis that is perpendicular to a ground upon which a user walks). 
     Still referring to  FIG.  6   , at block  112 , the expanded sole assembly may then be arranged within a forming frame. In some embodiments, the forming frame defines a size, shape, and structure that is similar to the second mold, except that the forming frame includes a plurality of frame pins, each frame pin having a smaller diameter, or size, than the diameter of a corresponding one of the channels  136 . In some embodiments, the plurality of frame pins can have a smaller diameter than the diameter of the of second pins in the second mold. When the intermediate sole assembly (e.g., the expanded sole assembly resulting from block  110  of process  100 ) is be arranged within the forming frame, the plurality of frame pins may be inserted into and through the plurality of channels in the intermediate sole assembly. 
     At block  114 , the expanded sole assembly is compressed by applying mechanical pressure to the expanded sole assembly (e.g., while the expanded sole assembly is within the forming frame) to compress the expanded sole assembly to a final size that is smaller than the intermediate size and to form a final sole assembly. The plurality of frame pins may prevent collapse of the plurality of channels in the sole assembly during the compression, and the smaller size defined by the plurality of frame pins, relative to the plurality of second pins, allows the plurality of channels to shrink down to the final size of the channels, which is smaller than the intermediate, or expanded size of the channels formed at block  110 . In some embodiments, each of the plurality of channels formed in the final sole assembly may be spaced from an adjacent channel by a maximum of about five millimeters in a heel-toe direction, which improves structural integrity of the final sole assembly and provides increased comfort to a wearer. With the final sole assembly formed at block  114 , the final sole assembly may be attached to an upper to form an article of footwear at block  116 . 
       FIGS.  15  and  16    illustrate another embodiment of a sole assembly  400  according to one aspect of the present disclosure. In general, the sole assembly  400  may be similar to the sole assembly  200 , with like features identified using the same reference numerals, except as described herein or as apparent from the figures. In the illustrated embodiment, sole assembly  400  includes a drop-in component or an upper midsole insert  402 . In some embodiments, the sole assembly  400  may be formed from the process outlined in the process  100 . In some embodiments, producing the sole assembly  400  includes forming the drop-in component  402  in a drop-in mold that includes a top mold surface (e.g., similar to the top mold surface  338  shown in  FIG.  12   ) and a bottom surface that includes a plurality of protrusions that form partial channels in the drop-in component  402 . 
     In the illustrated embodiment, the drop-in component  402  includes an upper surface  404  having a plurality of grooves  406  extending laterally along the upper surface  404  (see  FIG.  16   ). The grooves  406  are spaced from one another in the heel-toe direction  220 . In the illustrated embodiment, the grooves  406  are at least partially arranged within the midfoot region  224  and the forefoot region  226 . In general, the grooves  406  may provide increased flexibility to the sole assembly  400 . The drop-in component  402  includes a bottom surface  408  having a plurality of partial drop-in channels  410  extending laterally across the bottom surface  408  (see  FIG.  15   ). 
     In the illustrated embodiment, the sole assembly  400  defines an upper cavity  412  formed in an upper surface  414 . In general, the upper cavity  412  is dimensioned to receive the drop-in component  402  therein. The upper surface  414  includes a plurality of upper partial channels  416  that extend laterally across the upper surface  414 . The upper partial channels  416  may be formed by the pins  344  in the second mold  330 . When the drop-in component  402  is inserted into the upper cavity  412 , each of the plurality of upper partial channels  416  aligns with a corresponding one of the plurality of partial drop-in channels  410  to form a completed channel in the array of channels. 
       FIGS.  19 - 24    illustrate another embodiment of a sole assembly  702  according to aspects of the present disclosure. As illustrated in  FIG.  24   , the sole assembly  702  can include a first component  700  (e.g., an outsole). The sole assembly  702  illustrated also includes a second component  750 , and the first component  700  is at least partially received into the second component  750 . 
       FIGS.  19 - 21    illustrate the first component  700  of the sole assembly  702  according to one aspect of the present disclosure. In some embodiments, the first component  700  and the sole assembly  702  may be formed from the process outlined in the method  500  (see  FIG.  17   ) or the method  600  (see  FIG.  18   ). In some embodiments, the sole assembly  702  can be formed using techniques described with respect to process  100  (see  FIG.  6   ). In the illustrated embodiment, the first component comprises  700  comprises an outsole. The outsole may be fabricated from a first material. In some embodiments, the first material may comprise a polymer material, e.g., a thermoplastic material, polyurethane, etc. 
     In the illustrated embodiment, the first component  700  includes a plurality of tubes  704 , each including a generally hollow channel  706 . The plurality of tubes  704  extend laterally across the first component  700  from a lateral side  705  to a medial side  707 . Each of the plurality of tubes  704  is coupled to an upper surface  708  (i.e., a first surface) of the first component 700  by a base portion  710 . The plurality of tubes  704  extend outwardly from the upper surface  708  in a direction generally away from a bottom surface  711  (i.e., a second surface) of the first component  700 . Each of the base portions  710  may define a thickness that initially decreases and then increases as it extends from a respective one of the plurality of tubes  704  to the upper surface  708 , as shown in  FIG.  21   . 
     In general, the number of tubes  704  arranged within the first component  700  may vary depending on the desired performance characteristics of the first component  700 . The plurality of tubes  704  may be arranged only within a heel region  714 , or the plurality of tubes  704  may be spaced along the entire first component  700  between the heel region  714  and a forefoot region  716 . In the illustrated embodiment, the plurality of tubes  704  formed in the first component  700  are spaced along the first component  700  in a heel-toe direction  712  from the heel region  714  to a midfoot region  718  as shown in  FIG.  20   . In some embodiments, the plurality of tubes  704  formed in the first component  700  may be spaced along the first component  700  in the heel-toe direction  712  from the heel region  714  to the forefoot region  716 . In some embodiments, the plurality of tubes  704  formed in the first component  700  may be spaced along the first component  700  in the heel-toe direction  712  within the heel region  714 , as shown in  FIG.  19   . 
     With specific reference to  FIG.  21   , the plurality of tubes  704  may be formed by a first mold insert so that each of the plurality of tubes  704  is spaced from an adjacent tube  704  by a predetermined gap  720  in the heel-toe direction  712 . In some embodiments, the predetermined gap  720  may be a maximum of about five millimeters. In this way, rapid wear of the plurality of tubes  704  may be prevented. The described spacing can be sufficient to allow the tubes  704  to displace during a walking motion and provide increased comfort to a user. 
     Still referring to  FIG.  21   , each of the hollow channels  70   6  formed in the plurality of tubes  704  may define a diameter D. In some embodiments, the diameter D may be between about 6 and about 12 millimeters, or between about 7 and about 11 millimeters, or between about 8 and about 10 millimeters, or between about 9 and about 10 millimeters. As illustrated, each of the plurality of tubes  704  defines a wall thickness  722 . In some embodiments, the wall thickness  722  may be between about 2 and about 3 millimeters, or about 2.5 millimeters. Each of the base portions  710  may define a minimum thickness  724 . In some embodiments, the minimum thickness may be between about 2 and 5 millimeters, or between about 3 and 4 millimeters, or about 3.5 millimeters. In general, the dimensional ranges for the diameter D, the wall thickness  722 , and the minimum thickness  724  may ensure that the base portions  710  and the corresponding tubes  704  coupled thereto are structurally robust while maintaining sufficient flexibility to provide increased comfort to a wearer. 
       FIGS.  22  and  23    illustrate a second component  750  of the sole assembly  702  according to one aspect of the present disclosure. In some embodiments, the second component  750  and the sole assembly  702  may be formed from the process outlined in the method  500  or the method  600 , or from portions of the process  100 . In the illustrated embodiment, the second component  750  comprises a midsole. The midsole may be fabricated from a second material, which can comprise a polymer material, e.g., a thermoplastic material, polyurethane, etc. In some embodiments, the first material of the first component  700  is different than the second material of the second component  750  in at least one of color, density, hardness, and chemical composition. For example, the first material may comprise high density polyurethane (e.g., 0.5-1.2 g/cm 3 ) and the second material may comprise low density polyurethane. 
     In the illustrated embodiment, the second component  750  includes an upper surface  752  (e.g., a first surface), a bottom surface  754  (e.g., a second surface), a lateral side  756 , a medial side  758 , a heel region  760 , a midfoot region  762 , and a forefoot region  764 . In some embodiments, the second component  750  may include a plurality of apertures  766  that are formed in the bottom surface  754 . In the illustrated embodiment, the plurality of apertures  766  extend laterally across the second component  750  from the lateral side  756  to the medial side  758 . The size, shape, number, and arrangement of the plurality of apertures  76   6  formed in the second component  750  may be complementary to the plurality of tubes  704  formed in the first component  700 . For example, each of the plurality of apertures  766  defines a profile that conforms to a shape defined by a corresponding one of the plurality of tubes  704  and the accompanying base portion  710  attached thereto. Each of the plurality of apertures  766  may include a tube portion  768  that conforms to an outer surface of a corresponding one of the tubes  704  and a neck portion  770  that conforms to the outer profile of a corresponding one of the base portions  710 . 
     In general, the shape defined by the plurality of apertures  766  and the corresponding tube  704 /base portion  710  aid in retaining the tubes  704  within the apertures  766 . For example, each of the plurality of apertures  766  formed in the second component  750  may be dimensioned to receive a corresponding one of the plurality of tubes  704  from the first component  70   0 . The variable thickness defined by the base portions  710  and the corresponding neck portions  770  may aid in preventing the tubes  704  from being involuntarily removed from the apertures  766  because the minimum thickness  724 , which generally corresponds with the thickness of the neck portions  770 , is less than the diameter D of the tubes  704 . In this way, the plurality of tubes  704  are urged to remain within the plurality of apertures  766 . 
     In the illustrated embodiment, the upper surface  752  includes a plurality of grooves  772  extending laterally along the upper surface  752 . The grooves  772  are spaced from one another in the heel-toe direction  712 . In the illustrated embodiment, the grooves  772  are at least partially arranged within the midfoot region  762  and the forefoot region  764 . In general, the grooves  234  may provide increased flexibility to the second component  750  and the sole assembly  702 . 
     Turning to  FIG.  24   , the assembled sole assembly  702  is illustrated. In some embodiments, the sole assembly  702  may be formed using the method  500  where the first component  700  and the second component  750  are pre-molded prior to assembly. The first component  700  is then inserted into the second component  750  so that each of the plurality of tubes  704  may be received within a corresponding one of the plurality of apertures  766  to mechanically couple the first component  700  to the second component  750 , which forms the sole assembly  702 . The sole assembly  702  may be installed onto an upper to form an article of footwear. 
     In some embodiments, the sole assembly  702  may be formed using the method  600  where the second component  750  is overmolded onto the first component  700 . The sole assembly  702  may be installed onto an upper to form an article of footwear. 
       FIG.  17    outlines a method  500  for manufacturing a sole assembly (e.g., the sole assembly  702  illustrated in  FIG.  24   ) of an article of footwear according to some embodiments of the present disclosure. The method  500  may initiate at block  502  by forming a first component (e.g., the first component  700  illustrated in  FIGS.  19 - 21   ). The first component may be a molded component that is formed in a first mold. In some embodiments, the first component comprises an outsole. The first mold may include a first mold insert, a first mold plate, a first support frame, and a first set of slider pins that extend laterally through a cavity defined by the first mold (e.g., similar to the second mold  330  illustrated in  FIGS.  11 - 14   ). 
     The first mold insert may be fabricated from a wax, sand, or silicon material and may be enclosed between the first mold plate and the first support frame. In general, the inclusion of the first mold insert within the first mold enables the first component to be molded with undercuts and other complex geometries. In some embodiments, the first mold insert includes a plurality of cutouts or apertures that extend laterally across the first mold insert. The size and shape of the plurality of apertures define a size and shape of the corresponding tubes formed in the first component. That is, the absence of material defined by the apertures in the first mold insert may result in the formation of solid material being formed in the first component, e.g., negative geometries (no material) may result in the formation of positive geometries (solid material) in a molding process. In general, the first mold insert may be arranged within the first mold to define and form an upper surface of the first component. In some embodiments, the first mold insert may be arranged on top of the first mold plate (e.g., relative to a direction of gravity). 
     In some embodiments, the first mold plate may be fabricated from a metal or a silicon material. The first mold plate may be arranged below the first mold insert, e.g., relative to a direction of gravity, and may be arranged within the first mold to define and form a bottom surface of the first component. In some embodiments, the first support frame may be fabricated from a metal material. 
     To assemble the first mold, the first mold insert may be inserted into the first mold plate, so that a cavity is arranged (e.g., empty volume) between a top surface of the first mold plate and a bottom surface of the first mold insert. The cavity defines the size and shape of the formed first component. The first set of slider pins may be inserted through the apertures defined in the first mold insert. In general, the first set of slider pins may result in the formation of hollow channels being formed through the tubes in the first component. The first support frame may be inserted over the first mold insert to enclose the first mold insert between the first support frame and the first mold plate, if necessary. A first material may flow into the cavity defined between the first mold plate and the first mold insert to form the first component. In some embodiments, the first material may comprise a polymer material, e.g., a thermoplastic material, polyurethane, etc. 
     In some embodiments, the first component may include a plurality of tubes, each including a generally hollow channel formed by the first set of slider pins, that are formed by the apertures in the first mold insert. Each of the plurality of tubes may be coupled to an upper surface of the first component by a base portion, which is again formed by the size and shape of the apertures defined in the first mold insert. Each of the base portions may define a thickness that initially decreases and then increases as it extends from a respective one of the plurality of tubes to the upper surface. 
     In some embodiments, the plurality of tubes formed in the first component may be spaced along the first component in a heel-toe direction from a heel region to a midfoot region. In some embodiments, the plurality of tubes formed in the first component may be spaced along the first component in the heel-toe direction from a heel region to a forefoot region. In some embodiments, the plurality of tubes may be formed by the first mold insert so that each of the plurality of tubes is spaced from an adjacent tube by a maximum of about five millimeters in the heel-toe direction. For example, the apertures defined in the first mold insert may be spaced so that each of the plurality of tubes formed in the first component is spaced from an adjacent tube by a maximum of about five millimeters in the heel-toe direction. In this way, the plurality of tubes may be prevented against rapid wear and also may be spaced sufficiently to enable the tubes to displace during a walking motion and provide increased comfort to a user. 
     Once the first component is formed in the first mold, the first mold may be disassembled by removing the first set of slider pins and removing the first mold insert from the first mold plate. The first component may be decoupled from the first mold insert and the first mold insert may be reused to form more first components. 
       FIG.  25    illustrates a first mold  800  that may be used to form the first component  700  according to the method  500 . The first mold  800  includes a first mold insert  802 , a first mold plate  804 , a first support frame  806 , and a first set of slider pins  808  that extend laterally through a cavity defined by the first mold  800 . 
     In some embodiments, the first mold insert  802  may be fabricated from a wax, sand, or silicon material and may be enclosed between the first mold plate  804  and the first support frame  806 . In general, the inclusion of the first mold insert  802  within the first mold  800  enables the first component  700  to be molded with undercuts and other complex geometries (e.g., the tubes  704  and corresponding base portions  710  illustrated in  FIGS.  18 - 21   ). In the illustrated embodiment, the first mold insert  802  includes a plurality of cutouts or apertures  812  that extend laterally across the first mold insert  802 . The size and shape of the plurality of apertures  812  define a size and shape of the corresponding tubes  704  formed in the first component  700 . That is, the absence of material defined by the apertures in the first mold insert  802  may result in the formation of solid material being formed in the first component  700  (i.e., negative geometries (no material) may result in the formation of positive geometries (solid material) in a molding process). In general, the first mold insert  802  may be arranged within the first mold  800  to define and form the upper surface  708 , including the plurality of tubes  704  and base portions  710  of the first component  700 . 
     In some embodiments, the first mold plate  804  may be fabricated from a metal or a silicon material. As illustrated, the first mold plate  804  is arranged below the first mold insert  802 , relative to a direction of gravity  814 , and is arranged within the first mold  800  to define and form the bottom surface  711  of the first component  700 . In some embodiments, the first support frame  806  is fabricated from a metal material. 
     To assemble the first mold  800 , the first mold insert  802  may be inserted into the first mold plate  804 , so that a cavity (e.g., an empty volume) is arranged between a top surface  816  of the first mold plate  804  and a bottom surface  818  of the first mold insert  802 . The cavity defines the size and shape of the formed first component (e.g., the first component  700  shown in  FIGS.  19 - 21   ). In some embodiments, as shown, a first set of slider pins  808  are inserted through the apertures  812  defined in the first mold insert  802 . In general, the first set of slider pins  808  may result in the formation of the hollow channels being formed through the tubes in the first component (e.g., hollow channels  706  in the tubes  704  of the first component  700  shown in  FIGS.  19 - 21   ). In some embodiments, as shown, the first support frame  806  is inserted over the first mold insert  802  to enclose the first mold insert  802  between the first support frame  806  and the first mold plate  804 . The first material of the first component  700  can be injected into the cavity defined between the first mold plate  804  and the first mold insert  802  to form the first component (e.g., the first component  700  shown in  FIGS.  19 - 21   ). The first component may be removed from the first mold  800  and from the first mold insert  802 , and the first mold insert  802  may be reused to form additional first components  700 . 
     In general, the geometry defined by the first mold insert  802  defines a geometry of the formed first component  700 . For example, the predetermined gap  720  may be defined by the geometry of the first mold insert  802  and the spacing between the apertures  812 . In addition, the dimensions of the first set of slider pins  808  may define the diameter D and the wall thickness  722  of the plurality of tubes  704 . 
     Referring back to  FIG.  17   , with the first component formed at block  502 , a second component (e.g., the second component  750  illustrated in  FIGS.  22 - 24   ) may be formed at block  504 . The second component may be a molded component that is formed in a second mold. In some embodiments, the second component may comprise a midsole. The second mold may include a second mold insert, a second mold plate, and a second support frame. 
     The second mold insert may be fabricated from a wax, sand, or silicon material and may be enclosed between the second mold plate and the second support frame. In general, the inclusion of the second mold insert within the second mold enables the second component to be molded with undercuts and other complex geometries. In some embodiments, the second mold insert may include a plurality of solid tube protrusions that extend laterally across the second mold insert. The size and shape of the plurality of solid tube protrusions define a size and shape of the corresponding apertures formed in the second component. That is, the solid structure defined by the solid tube protrusions may result in the absence of material being formed in the second component, e.g., positive geometries (solid material) may result in the formation of negative geometries (no material) in a molding process. In general, the second mold insert may be arranged within the second mold to define and form a bottom surface of the second component. In some embodiments, the second mold insert may be supported by the second support frame. In some embodiments, the second mold insert may be arranged below the second mold plate, e.g., relative to a direction of gravity. 
     In some embodiments, the second mold plate may be fabricated from a metal or a silicon material. The second mold plate may be arranged on top of the second mold insert, e.g., relative to a direction of gravity, and may be arranged in the second mold to define and form an upper surface of the second component. In some embodiments, the second support frame may be fabricated from a metal material. 
     To assemble the second mold, the second mold insert may be inserted into the second support frame, and the second mold plate may be inserted onto the second mold insert so that a cavity is arranged (e.g., empty volume) between a bottom surface of the second mold plate and a top surface of the second mold insert. The cavity defines the size and shape of the formed second component. A second material may flow into the cavity defined between the second mold plate and the second mold insert to form the second component. In some embodiments, the second material may comprise a polymer material, e.g., a thermoplastic material, polyurethane, etc. In some embodiments, the first material may be different than the second material in at least one of color, density, hardness, and chemical composition when compared to the first material. For example, the first material may comprise high density polyurethane (e.g., 0.5-1.2 g/cm 3 ) and the second material may comprise low density polyurethane. 
       FIG.  26    illustrates a second mold  850  that may be used to form a second component (e.g., the second component  750 ) according to the method  500 . The second mold  850  includes a second mold insert  852 , a second mold plate  854 , and a second support frame  856 . 
     The second mold insert  852  may be fabricated from a wax, sand, or silicon material and may be enclosed between the second mold plate  854  and the second support frame  856 . In general, the inclusion of the second mold insert  852  within the second mold  850  enables the second component (e.g., the second component  750 ) to be molded with undercuts and other complex geometries (e.g., to form the plurality of apertures  766  shown in  FIGS.  22  and  23   ). In some embodiments, the second mold insert  852  may include a plurality of solid tube protrusions  858  that extend laterally across the second mold insert  852 . The size and shape of the plurality of solid tube protrusions  858  define a size and shape of the corresponding apertures  766  formed in the second component  750 . That is, the solid structure defined by the solid tube protrusions  858  may result in the absence of material being formed in the second component (e.g., positive geometries (solid material) may result in the formation of negative geometries (no material) in a molding process). In general, the second mold insert  852  may be arranged within the second mold  850  to define and form a bottom surface of the second component (e.g., the bottom surface  754  of the second component  750 , including the plurality of apertures  766  illustrated in  FIGS.  22  and  23   ). In some embodiments, the second mold insert  852  may be supported by the second support frame  856 . In some embodiments, the second mold insert  852  may be arranged below the second mold plate  854 , relative to the direction of gravity  814 . 
     In some embodiments, the second mold plate  854  may be fabricated from a metal or a silicon material. As shown, the second mold plate  854  is arranged on top of the second mold insert  852  relative to the direction of gravity  814  and arranged in the second mold  850  to define and form an upper surface of the second component, which can include grooves (e.g., the upper surface  752  of the second component  750 , including the grooves  772  shown in  FIGS.  22  and  23   ). In some embodiments, the second support frame  856  may be fabricated from a metal material. 
     In some embodiments, including as illustrated, to assemble the second mold, the second mold insert  852  is inserted into the second support frame  856 , and the second mold plate  854  is inserted onto the second mold insert  852  so that a cavity (e.g., an empty volume) is arranged between a bottom surface  860  of the second mold plate  854  and a top surface  862  of the second mold insert  852 . The cavity defines the size and shape of the formed second component (e.g., the second component  750 ). The second material may flow into the cavity defined between the second mold plate  854  and the second mold insert  852  to form the second component. The second component may be removed from the second mold  850  and from the second mold insert  852 , and the second mold insert may be reused to form additional second components (e.g., substantially identical to second component  750 ). 
     In general, the geometry defined by the second mold insert  852  defines a geometry of the formed first component (e.g., the first component  700  shown in  FIGS.  19 - 21   ). For example, the shape, size, and arrangement of the plurality of apertures  766  of the first component  700  shown in  FIGS.  19 - 21    may be defined by the solid tube protrusions  858  formed in the second mold insert  852 . 
     Referring back to  FIG.  17   , at block  506 , the second component is inserted into the first component to form a sole assembly (e.g., the first component  700  is inserted into the second component  750  to form the sole assembly  702  shown in  FIG.  24   ). In some embodiments, as described, the second component includes a plurality of apertures that are formed by the solid tube protrusions in the second mold insert. The size, shape, number, and arrangement of the plurality of apertures formed in the second component may be complementary to the plurality of tubes formed in the first component. In this way, each of the plurality of apertures formed in the second component may be dimensioned to receive a corresponding one of the plurality of tubes from the first component. Due to this complementary geometry defined between the plurality of apertures in the second component and the plurality of tubes in the first component, each of the plurality of tubes may be inserted into a corresponding one of the plurality of apertures to mechanically couple the first component to the second component at block  506 , to form the sole assembly. The sole assembly may be installed onto an upper to form an article of footwear. 
     In some embodiments, additional components can be formed and assembled in accordance with the techniques described with respect to  FIG.  17   . For example, a third component can be formed with a third mold, and can include complementary geometries to the second component, so that a sole assembly comprises three components. In some embodiments, the process  500  can be performed along with portions of the process  100 . For example, a sole assembly formed by process  500  can be a first portion of a sole assembly, and the first portion of the sole assembly can be inserted into the second mold at block  104  of process  100 , and overmolded with another component at block  108  to form a sole assembly. Further, the sole assembly produced by process  500  can be expended and contracted as described in blocks  110 ,  112 , and  114  of process  100 . 
       FIG.  18    outlines a method  600  for manufacturing a sole assembly of an article of footwear according to some embodiments of the present disclosure. The method  600  may initiate at block  602  by inserting a mold insert into a first mold base. In some embodiments, the first component may comprise an outsole. The first mold may include a mold insert, a first mold plate, a first mold base, and a first set of slider pins that extend laterally through a cavity defined by the first mold. 
     The mold insert may be fabricated from a wax, sand, or silicon material and may be enclosed between the first mold plate and the first mold base. In general, the inclusion of the mold insert within the first mold enables the first component to be molded with undercuts and other complex geometries. In some embodiments, the mold insert includes a plurality of cutouts or apertures that extend laterally across the mold insert. The size and shape of the plurality of apertures define a size and shape of the corresponding tubes formed in the first component. That is, the absence of material defined by the apertures in the mold insert may result in the formation of solid material being formed in the first component, e.g., negative geometries (no material) may result in the formation of positive geometries (solid material) in a molding process. In general, the mold insert may be arranged within the first mold to define and form an upper surface of the first component. In some embodiments, the mold insert may be arranged below the first mold plate, e.g., relative to a direction of gravity. For example, the first mold base may include a base cavity that is dimensioned to receive the mold insert therein. The mold insert may be inserted into the base cavity with the plurality of apertures facing an upward direction, e.g., away from the first mold base. 
     In some embodiments, the first mold plate may be fabricated from a metal or a silicon material. The first mold plate may be arranged above the mold insert, e.g., relative to a direction of gravity, and may be arranged in the first mold to define and form a bottom surface of the first component. In some embodiments, the first support frame may be fabricated from a metal material. 
     To assemble the first mold, the first mold insert may be inserted into base cavity of the first mold base at block  602 , and the first mold plate may be inserted onto the first mold insert so that a cavity (e.g., the empty volume) is arranged between a bottom surface of the first mold plate and a top surface of the mold insert. The cavity defines the size and shape of the formed first component. The first set of slider pins may be inserted through the apertures defined in the mold insert at block  604 . In general, the first set of slider pins may result in the formation of hollow channels being formed through the tubes in the first component. A first material may then be supplied to and flow into the cavity defined between the first mold plate and the mold insert to form the first component at block  606 . In some embodiments, the first material may comprise a polymer material, e.g., a thermoplastic material, polyurethane, etc. 
       FIGS.  27 - 29    illustrate a first mold  900  that may be used to form the first component  700  according to the method  600 . The first mold  900  includes a mold insert  902 , a first mold plate  904 , a first mold base  906 , and a first set of slider pins  90   8  that extend laterally through a cavity defined by the first mold  90   0 . 
     The mold insert  902  may be fabricated from a wax, sand, or silicon material and may be enclosed between the first mold plate  904  and the first mold base  906 . In general, the inclusion of the mold insert  902  within the first mold  900  enables the first component  700  to be molded with undercuts and other complex geometries (e.g., the tubes  704  and base portions  710 ). In the illustrated embodiment, the mold insert  902  includes a plurality of cutouts or apertures  910  that extend laterally across the mold insert  902  (see  FIG.  29   ). The size and shape of the plurality of apertures  910  define a size and shape of the corresponding tubes  704  and base portions  710  formed in the first component  700 . In general, the mold insert  902  may be arranged within the first mold  900  to define and form the upper surface  708  of the first component  700 . In some embodiments, as illustrated, the mold insert  902  is positioned below the first mold plate  904  relative to a direction of gravity  912 . For example, as shown in  FIG.  28   , the first mold base  906  may include a base cavity  914  that is dimensioned to receive the mold insert  902  therein. The mold insert  902  may be inserted into the base cavity  914  with the plurality of apertures  910  facing an upward direction, away from the first mold base  906  and opposite the direction of gravity  912 . 
     In some embodiments, the first mold plate  904  is fabricated from a metal or a silicon material. In the illustrated embodiment, the first mold plate  904  is be arranged above the mold insert  902 , relative to the direction of gravity  912 , and is arranged in the first mold  900  to define and form the bottom surface  711  of the first component  700 . 
     To assemble the first mold  900 , the mold insert  902  may be inserted into the base cavity  914 , and the first mold plate  904  may be inserted onto the mold insert  902  so that a cavity (e.g., an empty volume) is arranged between a bottom surface  916  of the first mold plate  904  and a top surface  918  of the mold insert  902 . The cavity defines the size and shape of the formed first component  700 . The first set of slider pins  908  may be inserted through the apertures  910  defined in the mold insert  902 . In general, the first set of slider pins  908  may form the hollow channels  706  in the tubes  704  of the first component  700 . The first material may be supplied to and flow into the cavity defined between the first mold plate  904  and the mold insert  902  to form the first component  700 . The first component  700  may be removed from the first mold  900  and from the mold insert  902  (see  FIGS.  28  and  29   ), and the mold insert  902  may be reused to form additional first components  700 . 
     In general, the design and arrangement of the mold insert  902  within the first mold base  906  may form the first component  700  in an upside-down configuration. For example, the first component  700  may be formed in the first mold  900  in an orientation that is upside down relative to an orientation of the first component in use, e.g., when installed on an article of footwear and worn by a user (see, e.g.,  FIG.  20   ). Specifically, the mold insert  902  arranges the plurality of apertures  910  in an orientation where the plurality of apertures  910  are lower than the remaining portions of the cavity defined between the mold insert  902  and the first mold plate  904 , e.g., relative to the direction of gravity  912 . In this way, the design of the first mold  900  can ensure that the first material flows into the plurality of apertures  910  and around the first set of slider pins  908  to form a plurality of tubes  704  in the first component  700 . 
     In general, the geometry defined by the mold insert  902  defines a geometry of the formed first component  700 . For example, the predetermined gap  720  may be defined by the geometry of the mold insert  902  and the spacing between the apertures  910 . In addition, the dimensions of the first set of slider pins  908  may define the diameter D and the wall thickness  722  of the plurality of tubes  704 . In other embodiments, a component of a first mold can be sized and arranged to produce first components (e.g., outsoles, midsoles, or portions of midsoles) having other geometries, including, for example, tubes having different diameters, different wall thicknesses, or defining different peripheral shapes. 
     Referring back to  FIG.  18   , once the first component is formed in the first mold by steps  602 - 606 , the first mold may be disassembled by removing the first set of slider pins and removing the mold insert from the first mold base. The first component may be decoupled from the mold insert and the mold insert may be reused to form more first components. The formed first component may then be inserted into a second mold base of a second mold at block  608 . The second mold may include the second mold base, a second mold plate, and a second set of slider pins. 
     The second mold base may include a second mold cavity being defined at least partially by a mold upper surface, e.g., a mold first surface, that is shaped to receive a bottom surface of the first component. In some embodiments, the second set of slider pins may be coupled to a pair of side walls that are movable relative to the second mold base. For example, a first portion of the second set of slider pins may be coupled to a first side wall, and a remaining portion of the second set of slider pins may be coupled to a second side wall. With the first component arranged within the second mold base, the first and second side walls may be installed onto the second mold base by sliding the first and second side walls onto the second mold base. In this way, for example, each of the plurality of tubes formed in the second component may receive a corresponding pair of the second set of slider pins therein, e.g., one slider pin may extend into a lateral side of the tube and another slider pin may extend into a medial side of the tube. Once the second set of slider tubes are arranged within the plurality of tubes formed in the first component, the second mold plate may be installed onto the second mold base. The second mold plate may include a mold bottom surface, e.g., a mold second surface, that is shaped to form an upper surface of the second component. A cavity (e.g., empty volume) defined between the mold bottom surface of the second mold plate and the first component may define the size and shape of the second component. A second material may then be supplied to and flow into the cavity at block  610 . The second material may flow over the first component and form a second component that is bonded and attached to the first component. The combination of the first component and the second component may form a sole assembly. In some embodiments, the second component may comprise a midsole. The sole assembly may be removed from the second mold and installed on an upper to form an article of footwear. 
     In some embodiments, the second material may comprise a polymer material, e.g., a thermoplastic material, polyurethane, etc. In some embodiments, the first material may be different than the second material in at least one of color, density, hardness, and chemical composition when compared to the first material. For example, the first material may comprise high density polyurethane (e.g., 0.5-1.2 g/cm 3 ) and the second material may comprise low density polyurethane. 
     In some embodiments, the second component may include a plurality of apertures that are formed by the second material flowing around the plurality of tubes in the first component. The size, shape, number, and arrangement of the plurality of apertures formed in the second component may be complementary to the plurality of tubes formed in the first component.  FIGS.  30 - 32    illustrate a second mold  950  that may be used to form the second component  750  and the sole assembly  702  according to the method  600 . The second mold  950  may include the second mold base  952 , a second mold plate  954 , and a second set of slider pins  956 . 
     The second mold base  952  may include a second mold cavity  958  being defined at least partially by a mold upper surface  960  (e.g., a mold first surface, shown in  FIG.  31   ) that is shaped to receive the bottom surface  711  of the first component  700  (see  FIG.  30   ). In the illustrated embodiment, the second set of slider pins  956  are coupled to a pair of side walls  962  that are movable relative to the second mold base  952 . For example, a first portion of the second set of slider pins  956  may be coupled to a first side wall  964 , and a remaining portion of the second set of slider pins  956  may be coupled to a second side wall  966 . With the first component  700  arranged within the second mold base  952 , the first and second side walls  964 ,  966  may be installed onto the second mold base  952  by sliding the first and second side walls  964 ,  966  laterally onto the second mold base  952 . In this way, for example, each of the plurality of tubes  704  formed in the first component  700  may receive a corresponding pair of the second set of slider pins  956  therein (e.g., one slider pin may extend into a lateral side of a tube  704  and another slider pin may extend into a medial side of the tube  704  as shown in  FIG.  31   ). Once the second set of slider pins  956  are arranged within the plurality of tubes  704  formed in the first component  700 , the second mold plate  954  may be installed onto the second mold base  952  (see  FIG.  32   ). 
     The second mold plate  954  may include a mold bottom surface  968 , e.g., a mold second surface, that is shaped to form the upper surface  752  of the second component  750  (e.g., as shown in  FIG.  22   ). A cavity  970  defined between the mold bottom surface  968  of the second mold plate  954  and the first component  700  may define the size and shape of the second component. The second material may be supplied to and flow into the cavity  970  to form the second component  750 . The second material may flow over the first component  700  and form the second component  750  that is bonded and attached to the first component  700 . The combination of the first component  700  and the second component  750  may form the sole assembly  702 . The sole assembly  702  may be removed from the second mold  950  and installed on an upper to form an article of footwear. The second mold  950  may be reused to form additional sole assemblies  702 . 
     While the process  600  in  FIG.  18    is described with respect to two components, in some embodiments, additional components can be formed according to the disclosed processes and techniques. For example, additional molds can be provided to overmold additional components to sole assemblies produced by any of methods  100 ,  500 , and  600 . Further, molds can be provided to produce other complex shapes in sole assemblies of shoes, through using inserts in molds to produce complex geometries as described in processes  500  and  600 , or to produce channels through engagement of a first and second component, as described with respect to process  100 . 
     Any of the embodiments described herein may be modified to include any of the structures or methodologies disclosed in connection with different embodiments. Further, the present disclosure is not limited to articles of footwear of the type specifically shown. Still further, aspects of the articles of footwear of any of the embodiments disclosed herein may be modified to work with any type of footwear, apparel, or other athletic equipment. 
     As noted previously, while the disclosure has been described above in connection with particular embodiments and examples, the disclosure is not necessarily so limited, and that numerous other embodiments, examples, uses, modifications and departures from the embodiments, examples and uses are intended to be encompassed by the claims attached hereto. The entire disclosure of each patent and publication cited herein is incorporated by reference, as if each such patent or publication were individually incorporated by reference herein. Various features and advantages of the invention are set forth in the following claims. 
     Industrial Applicability 
     Numerous modifications to the present disclosure will be apparent to those skilled in the art in view of the foregoing description. Accordingly, this description is to be construed as illustrative only and is presented for the purpose of enabling those skilled in the art to make and use the invention. The exclusive rights to all modifications which come within the scope of the appended claims are reserved.