Patent Publication Number: US-2018036944-A1

Title: Articles and Methods of Manufacture of Articles

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is (a) a continuation of co-pending U.S. patent application Ser. No. 12/433,097, filed Apr. 30, 2009 and entitled “Articles and Methods of Manufacture of Articles,” which application is (b) a continuation-in-part of U.S. patent application Ser. No. 12/255,496, filed Oct. 21, 2008 and entitled “Articles and Methods of Manufacture of Articles,” now U.S. Pat. No. 9,572,402 B2 issued Feb. 21, 2017. Each of U.S. patent application Ser. No. 12/433,097 and U.S. patent application Ser. No. 12/255,496 is incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to wearable articles and methods for the manufacture of these articles. More particularly, aspects of this invention relate to articles of footwear, and portions thereof, formed using rapid manufacturing additive fabrication techniques. 
     BACKGROUND 
     Various manufacturing processes exist to form a variety of manufactured articles, such as articles of footwear, apparel, athletic equipment, and the like. For example, a midsole for an article of footwear may be manufactured using one of a number of commonly used molding techniques, such as injection molding, blow molding, compression molding, vacuum molding, and the like. These molding methods often require expensive molding equipment that allows little room for variation in the articles produced from the mold. For instance, any change to the design of the molded article generally would require the creation of a new mold. These manufacturing methods generally required a costly retooling anytime a change was made to the molded article design. In addition, molding processes often result in material waste as some material may be trimmed from the molded article in a post-manufacturing processing step. 
     In addition, conventional molding and article manufacturing methods often leave little or no ability to customize the article, such as an article of footwear, to the particular needs or desires of the wearer. That is, conventional articles of footwear, apparel, athletic equipment, etc. are often mass produced. While some articles are produced in varying sizes, articles are rarely manufactured to the specifications of one particular user. 
     Further, articles, such as articles of footwear, have regions prone to wear, such as flex regions, high stress regions, etc. Early wear in these regions can cut short the useful life of the product while other areas of the product continue to be capable of functioning at a high level in the intended manner. 
     SUMMARY 
     The following presents a general summary of aspects of the invention in order to provide a basic understanding of the invention and various features of it. This summary is not intended to limit the scope of the invention in any way, but it simply provides a general overview and context for the more detailed description that follows. 
     Aspects of this invention relate to articles, such as articles of footwear, that include reinforcing regions. The articles of footwear (or portions thereof) may be formed using conventional techniques and materials and/or the articles of footwear (or portions thereof) may be formed using rapid prototyping techniques. The reinforcing regions may be formed as a portion of the shoe during fabrication of the shoe or may be formed separately and connected to the shoe using known means of attachment, such as adhesives, stitching, mechanical fasteners, and the like. 
     Additional aspects of the invention relate to various midsole impact attenuating configurations that may be formed using one or more rapid manufacturing additive fabrication techniques. For instance, a midsole may include a plurality of apertures that correspond to projections on an insole. The midsole and insole combination provide additional impact attenuation and the arrangement of the apertures and projections may be customized based on the specifications, desires, etc. of the wearer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete understanding of the present invention and certain advantages thereof may be acquired by referring to the following detailed description in consideration with the accompanying drawings, in which: 
         FIG. 1  generally illustrates a side view of an example article of footwear formed according to this invention. 
         FIG. 2  is a side view of an example article of footwear having reinforced regions formed according to aspects of this invention. 
         FIG. 3  is a side view of another example article of footwear having reinforced regions formed according to aspects of this invention. 
         FIG. 4  is a side view of still another example article of footwear having reinforced regions formed according to aspects of this invention. 
         FIG. 5  is a side view of example article of footwear, portions of the article of footwear being formed from different materials according to aspects of this invention. 
         FIGS. 6A and 6B  are top and cross section views, respectively, of a midsole impact force attenuation system having corresponding apertures and projections and formed according to aspects of this invention. 
         FIG. 7  is an example airbag impact attenuating system formed according to aspects of this invention. 
     
    
    
     The reader is advised that the attached drawings are not necessarily drawn to scale. 
     DETAILED DESCRIPTION 
     In the following description of various example structures in accordance with the invention, reference is made to the accompanying drawings, which form a part hereof, and in which are shown by way of illustration various example articles and methods for manufacturing these articles, such as footwear, watchbands, apparel, athletic equipment, and the like. Additionally, it is to be understood that other specific arrangements of parts and structures may be utilized, and structural and functional modifications may be made without departing from the scope of the present invention. Also, while the terms “top,” “bottom,” “front,” “back,” “rear,” “side,” and the like may be used in this specification to describe various example features and elements of the invention, these terms are used herein as a matter of convenience, e.g., based on the example orientations shown in the figures and/or the orientations in typical use. Nothing in this specification should be construed as requiring a specific three dimensional or spatial orientation of structures in order to fall within the scope of this invention. Further, the invention will generally be described in accordance with an article of footwear and method of manufacturing an article of footwear. However, the invention may be used in production of a variety of articles. 
     A. General Description of Articles, Such as Footwear, According to Examples of the Invention 
     In general, as described above, aspects of this invention relate to articles, such as footwear, watchbands, articles of apparel, athletic equipment, and the like. In addition, aspects of this invention relate to methods of manufacturing such articles. More detailed descriptions of aspects of this invention follow. 
     1. Example Articles, Such as Articles of Footwear, According to the Invention 
     One aspect of this invention relates to articles, such as articles of footwear. Such articles of footwear may include, for example, an upper and a sole structure engaged with the upper. In at least some examples, the upper and/or sole structure may be formed using rapid manufacturing techniques, such as laser sintering, solid deposition modeling, stereolithography, and the like. The upper may include reinforcement portions configured to provide additional durability, wear resistance, etc., in areas of the upper that may be prone to tearing, wear, flex, and the like. The reinforcement portions may be formed of conventional materials and manufacturing processes, for instance, non-rapid manufacturing additive fabrication techniques, or they may be formed using one or more rapid manufacturing additive fabrication techniques. The reinforcement portions may be connected to the upper using known means of attachment, such as stitching, adhesives, and the like. 
     In other examples, portions of the rapid manufactured upper and/or sole structure of the article of footwear may be formed of different materials to provide different mechanical characteristics to different regions of the shoe. For instance, flexible regions may be formed of a first material having properties associated with flexibility to enable flexing of the shoe, while supportive regions, such as an ankle region, may be formed of a second material having properties associated with stiffness and support. In at least some products in accordance with this invention, the various portions of the shoe may be formed in a single rapid manufacturing process. 
     In still other examples, portions of the rapid manufactured upper and/or sole structure of the article of footwear may be formed from material fused with varying laser intensities in order to provide different mechanical characteristics to different regions of the shoe. For instance, regions in which greater hardness is desired, such as an eyelet region, may receive a higher intensity laser than regions in which flexibility is desired, such as the toe region. Laser radiation intensity may be varied, for example, by altering the laser power, the laser scanning speed, or the laser beam spot size. 
     Specific examples of the invention are described in more detail below. The reader should understand that these specific examples are set forth merely to illustrate examples of the invention, and they should not be construed as limiting the invention. 
     B. Specific Examples of the Invention 
       FIG. 1  generally illustrates an example article of footwear  100  formed according to aspects of the invention. The article of footwear  100  includes an upper  102  and a sole structure  104 . For purposes of reference in the following material, footwear  100  may be divided into three general regions: a forefoot or toe region  111 , a midfoot region  112 , and a heel region  113 , as illustrated in  FIG. 1 . In addition, footwear  100  includes two sides: lateral side  114  and medial side (not shown). Lateral side  114  is positioned to extend along the lateral (outside) side of the foot and generally passes through each of regions  111 - 113 . Similarly, the medial side is positioned to extend along an opposite medial (inside) side of the foot and generally passes through each of regions  111 - 113 . Regions  111 - 113  and medial and lateral sides are not intended to demarcate precise areas of footwear  100 . Rather, regions  111 - 113  and medial and lateral sides are intended to represent general areas of footwear  100  that provide a frame of reference during the following discussion. 
     Generally, upper  102  is secured to sole structure  104  and defines a cavity for receiving a foot. Access to the cavity is provided by an ankle opening  106  located in heel region  113 . A lace  108  extends through various apertures in upper  102 . Lace  108  may be utilized in a conventional manner to selectively increase a size of ankle opening  106  and to modify certain dimensions of upper  102 , particularly girth, to accommodate feet with varying dimensions. Various materials are suitable for use in manufacturing a conventional upper. Those materials used in conventional uppers include leather, synthetic leather, rubber, textiles, and polymer foams, for example, that are stitched or adhesively bonded together. The specific materials utilized for upper  102  may be selected to impart wear-resistance, flexibility, air-permeability, moisture control, and comfort. In some conventional arrangements, different materials may be incorporated into different areas of upper  102  in order to impart specific properties to those areas. Furthermore, the materials may be layered in order to provide a combination of properties to specific areas. In accordance with aspects of this invention, the upper  102  may be formed using a rapid manufacturing additive fabrication technique from suitable materials, such as a thermoplastic elastomer, and may include various reinforcements formed using conventional methods, as well as by using rapid manufacturing additive fabrication techniques, as will be discussed more fully below. 
     Sole structure  104  is secured to a lower surface of upper  102  and includes an outsole  120  and a midsole  122 . Outsole  120  forms a ground-engaging surface of sole structure  104  and is formed of a durable, wear-resistant material. Conventional sole structures may be formed of rubber that is textured to enhance traction. In accordance with aspects of this invention, the outsole  120  and/or midsole  122  may be formed, using a rapid manufacturing additive fabrication technique, of a thermoplastic elastomer, as will be discussed more fully below. In some embodiments, outsole  120  may be integrally formed with midsole  122  or may be a lower surface of midsole  122 . Some conventional midsoles are primarily formed of a polymer foam material, such as polyurethane or ethylvinylacetate, that forms a foam core type impact force attenuation system in the midsole  122 . Other conventional midsoles may include a column type midsole impact force attenuation system, such as the one shown in  FIG. 1 . Additional midsole impact force attenuation types are available for use in conventional midsoles, including an air bag type impact force attenuation system. These various impact force attenuation systems, including column type, foam core, air bag, and the like (or at least portions thereof), may also be manufactured using rapid manufacturing techniques and associated materials in accordance with aspects of this invention, as will be discussed more fully below. 
     Conventional articles of footwear are generally formed from a variety of different types of materials and a variety of different manufacturing processes. In some arrangements, the upper and sole structure are generally formed as separate pieces and then are joined in a post-manufacture processing step. In forming the upper, a plurality of upper portions may be formed or cut, using conventional methods, and then are connected to each other. The upper portions may be connected by any known means such as stitching, adhesives, mechanical fasteners, and the like. This process often generates a substantial amount of waste associated with trimming each of the individual pieces of the upper to be the correct shape and size for that particular upper or portion of the upper. 
     In addition to forming articles of footwear using conventional manufacturing techniques, the articles of footwear, or portions thereof, may be formed using rapid manufacturing additive fabrication techniques, such as laser sintering, stereolithography, solid deposition modeling, and the like. Rapid manufacturing fabrication techniques involve creating a three-dimensional design in a data file, such as a Computer Aided Design (CAD) file, and building the object of the three-dimensional design in an automated layer by layer process. Essentially, the fabrication equipment reads the three-dimensional design from the data file and lays down successive layers of powder, liquid or sheet material to build the three dimensional object. The layers are joined together by the fabrication equipment, for instance, a high powered laser may be used, to form the three dimensional object of the design. Such rapid manufacturing techniques are generally known in the art. 
     One particular process for forming articles that may be used in accordance with aspects described herein is laser sintering. This process involves creating a three-dimensional design in a data file, such as a CAD file. The laser sintering fabrication equipment reads the CAD file and forms the three-dimensional object of the design, such as an upper or portion of an upper for an article of footwear, using a high powered laser to fuse powders or small particles of plastic, metal or ceramic. The laser selectively fuses powdered material by scanning cross-sections generated from a CAD file or a scan of the part on the surface of a powder bed. After each cross-section is scanned, the powder bed is lowered by one layer thickness, a new layer of material is applied on top, and the process is repeated until the part is completed. Laser sintering, and other rapid manufacturing processes are generally known in the art. One example system is found in U.S. Pat. No. 5,156,697 to Bourell et al. and is incorporated herein by reference. 
     Articles of footwear formed using rapid manufacturing additive fabrication techniques, and some formed using conventional methods, often require reinforcement at areas that experience flexing or heavy wear or stress. Accordingly, reinforcement portions may be formed to prolong the usable life of the article of footwear by reinforcing the region prone to weakening, tearing, etc. For instance,  FIG. 2  illustrates one example article of footwear  200  including reinforcement portions  202 ,  204 . As shown, the article of footwear  200  generally includes an upper  206  forming a void for receiving a foot of a wearer. In addition, the shoe  200  includes a sole structure  208  that may include a midsole  210  and an outsole  212 . In some examples, the sole structure  208  may be formed using conventional methods, such as molding, etc. In other arrangements, the sole structure  208  may be formed using one or more rapid manufacturing additive fabrication techniques. Forming the sole structure  208  using rapid manufacturing techniques may permit complex shapes to be formed, some of which may be impossible to form using conventional manufacturing techniques. Also, forming the sole structure  208  using rapid manufacturing techniques may better allow for customization of the sole structure  208 , because the foot of a wearer may be scanned and the sole structure  208  may be manufactured based on the scan of the wearer&#39;s foot. 
     The upper  206  may also be formed using conventional manufacturing techniques or rapid manufacturing additive fabrication techniques. The article of footwear  200  of  FIG. 2  also includes a plurality of eyelets  203 . In some arrangements, the upper  206  formed using rapid manufacturing techniques may benefit from reinforcement of the eyelet regions of the article  200 . Accordingly, eyelet reinforcement portions  202  may be formed and connected to the upper  206  using known means of attachment, such as stitching, adhesives, mechanical fasteners, and the like. For instance, eyelet reinforcement  202  may be formed using rapid manufacturing techniques and connected to the eyelet region  203  of the upper  206  in order to reinforce the eyelets  203  to accommodate a lace or other closure system (not shown). In another example, the eyelets reinforcements  202  may be formed from conventional material (e.g., plastic, metal, leather, textile, etc.) and/or from conventional manufacturing techniques such as molding, extrusion, etc. The eyelet reinforcements  202  may then be connected to the eyelets  203  formed in the upper  206  as a post-manufacturing processing step using known means of attachment, such as stitching, adhesives, mechanical fasteners, crimped metal ring structures, mating snap fit components on the reinforcement and the upper, and the like. 
     The article of footwear  200  of  FIG. 2  also includes a reinforcement  204  configured at a toe region of the article of footwear  200 . In some arrangements, the toe region may be considered a high wear region due to a wearer&#39;s toe pushing on the inner side of the toe region during use. Accordingly, a regional reinforcement structure, such as reinforcement  204 , may be positioned in that region to aid in preventing holes, tearing, etc. The toe region reinforcement  204  may be formed from conventional materials, such as textile, leather, and the like, or it may be formed using a rapid manufacturing additive fabrication technique and associated materials. Using a rapid manufacturing technique to form the reinforcement  204  may permit variations in the thickness of the reinforcement in various regions of the reinforcement. For instance, the reinforcement may be thinner at the rear of the toe region (i.e., closer to the midfoot region of the shoe) rather than at the front of the toe region to provide additional support at the front of the shoe. 
     Further, the shape, size, thickness, etc. of the reinforcement  204  may be customized for a particular wearer. That is, the gait or step cycle and characteristics of the wearer may be studied in order to determine where additional reinforcement may be needed and the reinforcement  204  may be constructed to those specifications using one or more rapid manufacturing additive fabrication techniques or, in some arrangements, conventional manufacturing techniques. As one more specific example, for persons that tend to over-pronate during their steps, additional stiffness and/or wear reinforcement may be provided in the lateral heel area of the sole. 
     The toe region reinforcement  204  may be connected to the upper  206  using known means of attachment, such as adhesives, stitching, mechanical fasteners, mating snap fit components on the reinforcement and the upper, and the like. 
     Additionally or alternatively, the vamp forefoot region includes a flex region that may also benefit from reinforcement. For instance,  FIG. 3  illustrates an article of footwear  300  having a reinforcement  302  extending along this flex region of the upper  306 . The reinforcement  302  may be formed of conventional materials and/or conventional manufacturing techniques, or may be formed using a rapid manufacturing additive fabrication technique and associated materials. The reinforcement  302  may be formed as part of the initial rapid manufacturing process to fabricate the article of footwear  300 , or it may be formed as a separate piece that may be connected or attached to the upper  306  using known means of attachment, such as adhesives, stitching, mechanical fasteners, mating snap fit components on the reinforcement and the upper, and the like. The reinforcement  302  may be formed to permit flexing of the article of footwear  300  in that region, while providing additional durability and wear resistance in the high stress area of the shoe  300  (for example, when jumping, crouching, etc.). 
       FIG. 4  illustrates yet another article of footwear  400  having a reinforced region  402 . As with the arrangements above, the upper  406  and sole structure  408  of the article of footwear  400  may be formed using conventional materials and conventional manufacturing techniques, or they may be formed using one or more rapid manufacturing additive fabrication techniques and associated materials. However, the collar region  402  of the article of footwear  400  is often a region that receives heavy wear and may be likely to tear, wear down, etc. Accordingly, reinforcement in the collar region  402  may prolong the usable life of the shoe  400 . 
     In some arrangements, the upper  406  of an article of footwear  400  may be formed using one or more rapid manufacturing additive fabrication techniques. A collar reinforcement  404  may be formed separately (either from conventional materials and processes or rapid manufacturing materials and processes) and connected to the upper  406  to provide additional wear resistance. Additionally, because the collar region  402  may be an area that can rub and cause irritation on the wearer&#39;s skin, the collar reinforcement  404  also may include a soft foam, fabric, or other comfort-enhancing material. The collar reinforcement  404  may be attached to the upper  406  using known means of attachment including stitching, adhesives, mechanical fasteners, and the like. In some arrangements, the collar reinforcement  404  may include a snap fit mechanism that mates with a corresponding snap fit mechanism configured in the collar region  402  of the upper  406 . 
     In addition to providing added strength, wear resistance, comfort, etc., the reinforcements described above may also add various design elements to the article of footwear. For instance, the reinforcements may include one or more colors or color schemes to complement the color or colors used in the upper or other portions of the shoe. Additionally or alternatively, the reinforcements may be shaped to provide a complimentary design element to the shoe structure. In some arrangements, the reinforcements may be shaped to include a logo (such as a team logo, mascot, etc.) or a company trademark. In some arrangements, the properties of one region may transition into the properties of another region. 
     Further, resin (colored or uncolored) may be brushed, painted, sprayed, etc. onto various regions of an article of footwear formed using rapid manufacturing techniques to provide additional aesthetic enhancement, as well as additional durability to regions of high wear and/or stress. The resin may be brushed onto the shoe after the shoe has been formed, as a post-fabrication processing step. The process may include resins of varying colors, etc. in order to enhance the appearance of the shoe while providing added durability to various regions of the shoe or to the entire shoe, as desired. Various resins that may be used and techniques for applying the resin are discussed more fully in U.S. patent application Ser. No. 12/255,496, entitled “Articles and Methods of Manufacture of Articles” to which this application claims priority and which is incorporated herein by reference in its entirety. 
     In addition to the reinforcement portions and techniques described above, an article of footwear may be formed using more than one material during a rapid manufacturing additive fabrication process. For instance, the article of footwear may be formed from a single design file including the design, specifications, etc. of the shoe. During rapid manufacturing of the shoe, using a single type of rapid manufacturing process, multiple materials may be used to provide different characteristics or properties to different regions of the shoe. 
     For instance, the article of footwear  500  in  FIG. 5  may be formed using one or more rapid manufacturing additive fabrication techniques. The layer-by-layer process used to fabricate the shoe  500  may include different materials for different regions of the shoe  500 . For instance, additional flexibility may be desired in a toe region  502  of the shoe  500 , while additional stiffness may be desired in the lateral side  504  and medial side (not shown) of the upper  506  being formed. Materials providing these differing properties may be used in the same rapid manufacturing additive fabrication technique. For instance, a layer of the powder being fused may include a first material in one area or portion of the article and a second material, different from the first material, in another area or portion of the article. Accordingly, two or more different materials may be used to form, from a single rapid manufacturing process, the shoe  500  having the desired properties. In some examples, portions of the article of footwear may be formed using a thermoplastic elastomer, such as DuraForm Flex plastic manufactured and sold by 3D Systems, or other similar materials, such as manufactured by Advanced Laser Materials, LLC (e.g., ALM Flex) and Evonk Industries (e.g., Evonik Soft Touch), various powders, any generally plastic-like material, and the like. 
     In still other arrangements, the rapid manufacturing additive fabrication technique used to manufacturing the article may include a laser having varying intensities, such that higher or lower intensities may be used when forming various regions of the article of footwear. For instance, with further reference to  FIG. 5 , the toe region  502  may be fused using a laser of lower intensity in order to maintain the flexibility of the material in that region. However, a higher intensity laser may be used to fuse the material of the lateral side  504  and medial side of the upper  506  in order to provide additional stiffness and support in those regions. This arrangement using lasers of varying intensities in different regions of the foot may be performed using various known rapid manufacturing additive fabrication techniques. Further, various lasers may be used to manufacture the articles. In some arrangements, a 50 watt carbon dioxide DEOS Class IV laser may be used. 
     In other arrangements, regions in which additional hardening would be desired, such as the eyelet region ( 203  of  FIG. 2 ), may be fused with a higher intensity laser than other regions of the shoe. This may aid in reinforcing the eyelet region of the article. 
     Varying the intensity of the laser may permit further customization of the article of footwear. For instance, varying the intensity of the laser used in fabricating various regions of the shoe may alter the density, stiffness, etc. of the shoe such that the article being formed may be “tuned” to desired specifications. These specifications may be unique to one or more identified users. This arrangement provides the ability to alter the properties of the article for each shoe fabricated, if desired, without requiring costly molds to be manufactured in order to produce the articles. 
       FIGS. 6A and 6B  illustrate yet another arrangement of a portion of an article of footwear that may be formed using one or more rapid manufacturing additive fabrication techniques.  FIG. 6A  illustrates a top view of a midsole  600  of an article of footwear. The midsole  600  generally includes a plurality of apertures  602  distributed throughout a top surface  604 . The apertures  602  may extend through a portion of the midsole  600  or may extend completely through the midsole  600  from the top surface  604  to a bottom surface  606 .  FIG. 6B  is a cross section of the midsole  600  of  FIG. 6A  taken along line A-A. The figure illustrates one example in which the apertures  602  extend partially through the midsole  600 . The midsole  600  may be formed using one or more rapid manufacturing additive fabrication techniques. Using these techniques will allow any number, shape, arrangement, size, etc. of apertures to be formed in the midsole  600 . For instance, larger or smaller apertures may be formed, apertures of varying shapes including square, rectangular, triangular, trapezoidal, hexagonal, etc. may be formed, the pattern of apertures may vary depending on the region of the midsole, etc. 
       FIG. 6B  further includes an insole member  610 . The insole member  610  includes a base  612  and a plurality of projections  614 . The projections  614  are formed of a shape and size to correspond to the apertures  602  formed in the midsole  600 . The insole member  610  and projections  614  may provide additional impact attenuation, support, comfort, etc. for the wearer. The insole member  610  may be formed using a rapid manufacturing additive fabrication technique or by conventional techniques. 
     In some arrangements, the size, arrangement, etc. of the apertures  602  and corresponding projections  614  may be customized to a particular user. For instance, a scan of a wearer&#39;s foot may be taken and additional impact attenuation may be provided in various regions based on the results of the scan. 
     In still other arrangements, rapid manufacturing additive fabrication techniques may be used to form inserts for airbags to be used in midsole impact attenuation systems. For instance, a midsole may include an inflated airbag formed of conventional materials. The airbag may include an insert to aid in maintaining the desired shape of the airbag. For instance, the insert may be attached to the airbag at various locations in the bag interior to help control the shape of the airbag when it is inflated. The use of rapid manufacturing to fabricate the insert allows the insert to be customized to the needs and/or desires of the wearer, as well as to any desired size, shape, etc. in order to maintain the desired shape of the airbag.  FIG. 7  illustrates one example airbag  700  including an insert  702  formed using one or more rapid manufacturing additive fabrication techniques. The insert  702  may be sized, shaped, configured, etc. based on a user&#39;s desires, specifications based on features of a user&#39;s foot, etc. 
     In still other arrangements, one or more structures arranged in the midsole to hold or fasten the airbag in place may be formed using one or more rapid manufacturing additive fabrication techniques. For example, brackets, clips, grooves, frames, pockets, or other structures for securing the airbag that may be difficult or impossible to manufacture using conventional methods of manufacture may be formed using rapid manufacturing. 
     In still other arrangements, various parts may be manufactured using rapid fabrication additive techniques inside of other parts formed from the same process. For instance, a small part may be manufactured inside a hollow cavity in a larger part to save time and materials. This process would be similar to Russian dolls with smaller dolls nesting inside larger ones. The CAD file created may include the design for the small part and the larger part and the part may be manufactured in one process. 
     Further still, some articles manufactured using rapid fabrication additive techniques may be formed in a collapsed condition in order to conserve space. For instance, similar to a paper bag that is stored collapsed along various creases and fold lines, the articles may be formed using rapid manufacturing in a collapsed condition then expanded upon use. 
     For example, an article of footwear may be formed of a plurality of interlocking rings. The rings may vary in size in different regions of the article of footwear or may be the same size throughout. During manufacture of the article, the rings may be formed in a collapsed condition. That is, the rings may be formed in a stacked formation to produce an article having a very compact shape. However, the rings may be expanded upon opening or expansion of the article to provide the article in an expanded and/or usable condition. 
     Although the above arrangements have been described for use in manufacturing articles of footwear, aspects of the invention may be used with a variety of articles including apparel, athletic equipment, such as hockey sticks, shin guards, lacrosse sticks, shoulder pads, etc., watch bands, jewelry, eye glasses, and the like. 
     The arrangements described above allow for customization of articles based on a user&#39;s specification, desires, etc. In addition, the use of rapid manufacturing fabrication techniques to form various articles minimizes material waste associated with manufacturing the article. When manufacturing conventional articles, material is often trimmed from the article in order to obtain the desired size or shape of the article. In the method described herein, the three-dimensional design file can be created having the particular desired dimensions of the article. The article is then built to those particular dimensions. No additional material is created that may need to be removed to obtain the desired size and shape of the article. 
     CONCLUSION 
     While the invention has been described in detail in terms of specific examples including presently preferred modes of carrying out the invention, those skilled in the art will appreciate that there are numerous variations and permutations of the above described systems and methods. Thus, the spirit and scope of the invention should be construed broadly as set forth in the appended claims.