Patent Publication Number: US-2021187793-A1

Title: Method Of Forming A Mold Tool For Poured Foam Parts

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority of U.S. Provisional Patent Application No. 62/979,757, filed Dec. 18, 2020, and U.S. Provisional Patent Application No. 62/951,137, filed Dec. 20, 2020, the disclosures of which are incorporated herein by reference in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a method of forming a mold tool for manufacturing poured foam parts. 
     2. Description of Related Art 
     It is generally known to manufacture a foam part by pouring liquid polyurethane foam into a mold tool. The mold tool comprises a bottom mold forming a cavity defining the desired shape of the foam part and a top lid for closing the mold. The liquid polyurethane foam is poured into the cavity of the bottom mold and the top lid is closed over the mold. The liquid polyurethane foam is allowed to expand in the mold tool until the foam sets to the desired shape as defined by the cavity of the mold. The mold tool is typically formed by casting, machining, and assembling various components such as heating/cooling lines, hinges, and vents to make the bottom mold and top lid. 
     However, the casting and machining of the mold tools is expensive and time consuming. The casting of mold tools is thus often not practical for producing prototype parts or when mold tools are needed on a fast timeline for production. Also, each foam part requires a unique mold tool to form the specific and desired shape of the foam part. Thus, it is also expensive to cast a new mold tool for every new foam part or each change in an existing foam part. 
     Therefore, it is desirable to provide a method of manufacturing a mold tool for manufacturing poured foam parts wherein the method includes 3D printing a composite mold tool to form a mold cavity for forming the poured foam parts. The 3D printing significantly decreases the time and expense required for producing a mold tool whether for prototype or full production foam parts. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: 
         FIG. 1  is a perspective view of a mold tool for use in manufacturing a poured foam part in the closed position; 
         FIG. 2  is a fragmentary perspective view of the mold tool in an open position; 
         FIG. 3  is a front perspective view of the mold tool in the open position; 
         FIG. 4  is a side perspective view of the mold tool in the open position; 
         FIG. 5A  is an example of the 3D printing data, parameters and process for forming the mold tool; 
         FIG. 5B  is a cross-sectional view of the 3D printed lower mold of the mold tool; 
         FIGS. 6A-6E  are top views of the various stages or layers of the 3D printed lower mold; 
         FIGS. 7A-7E  are side view of the various stages or layers of the 3D printed lower mold; 
         FIG. 8  is a plan view of a first embodiment of an infill pattern used in the embodiment of  FIGS. 1-7  showing a 3D crisscross lattice pattern for the infill; 
         FIG. 9A  is a plan view of an alternate second embodiment of an infill pattern showing a 3D Gyroid lattice pattern for the infill; 
         FIG. 9B  is a perspective view of a mold body with a gyroid pattern for the infill; 
         FIG. 10  is a perspective view of a second embodiment of a mold tool for use in manufacturing a poured foam part in the closed position; 
         FIG. 11  is a front perspective view of the mold tool of  FIG. 10  in an open position; 
         FIG. 12  is a front perspective view of the mold tool in the closed position; 
         FIG. 13  is a front perspective view of a third embodiment of a mold tool for use in manufacturing a poured foam part in the closed position; 
         FIG. 14  is a rear perspective view of a top lid for the mold tool of  FIG. 13  and an upper mold insert thereof; 
         FIG. 15  is a rear perspective view of the mold tool in a closed position showing an upper heating unit therefor; 
         FIG. 16  is a top view of the upper heating unit; 
         FIG. 17  is a partial front perspective of the mold tool in the open position showing the lower mold with a lower mold insert; 
         FIG. 18  is a bottom perspective view of a bottom mold panel with the bottom mold insert and support panel therefor; 
         FIG. 19  is a bottom view a lower heating unit; 
         FIG. 20  is an example of the 3D printing data, parameters and process for forming the mold tool with a gyroid pattern; 
         FIGS. 21A-21B  are top views of the various stages or layers of the 3D printed upper mold body of the embodiment of  FIG. 10 ; and 
         FIGS. 21C-21D  are top views of the various stages or layers of the 3D printed lower mold body of  FIG. 10 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the Figures, wherein like numerals indicate like or corresponding parts throughout the several views, a mold tool for use in manufacturing a poured foam part according to a first embodiment of the invention is shown at  10  in  FIGS. 1-4 . The poured foam part manufactured with use of the mold tool  10  and the remaining embodiments disclosed herein may be any type of part such as a seat cushion, seat back, head restraint, or any other polyurethane foam part. 
     The mold tool  10  comprises a lower mold  12  defining a recessed mold cavity  14  extending between a top mold surface  16  and a bottom mold surface  18 . The mold cavity  14  may be formed as an upward opening bowl for receiving poured foam during the mold operation. The lower mold  12  also includes spaced apart side walls  20 ,  22  extending between a front wall  24  and a back wall  26  and surrounding the mold cavity  14 . 
     The mold tool  10  further comprises an upper mold  28 , or lid, pivotally coupled to the lower mold  12  for closing the mold cavity  14 . The upper mold  28  similarly includes a top surface  30 , a bottom surface  32  for engaging the top surface  16  of the lower mold  12  and closing the mold cavity  14 , and spaced apart side walls  34 ,  36  extending between a front wall  38  and back wall  40 . A mold lid  41  is formed in the bottom mold surface  32 , preferably projecting therefrom, for mating with the mold cavity  14  although the mold lid  41  may also have at least a portion recessed into the bottom mold surface  32 . 
     One or more pivot hinges  42  are fixedly secured between the back wall  40  of the upper mold  28  and the back wall  26  of the lower mold  12  for pivotally coupling the upper mold  28  to the lower mold  12  between an open position providing access to the mold cavity  14 , as shown in  FIGS. 2-4 , and a closed position covering the mold cavity  14 , as shown in  FIG. 1 . One or more clamps  44  are operatively coupled between the upper mold  28  and lower mold  12  for clamping the mold tool  10  in the closed position. Each clamp  44  includes a first clamp base  46  fixedly secured to the front wall  24  of the lower mold  12  for pivotally supporting a clamp latch  48  and a second clamp base  50  fixedly secured to the front wall  38  of the upper mold  28  for supporting a clamp lip  52 . The clamp latch  48  locking engages with the clamp lip  52  to releasably lock the mold tool  10  in the closed position as shown in  FIG. 1  and releases from engagement with the clamp lip  52  to allow the mold tool  10  in the open position as shown in  FIGS. 2-4 . 
     Finally, each of the lower mold  12  and upper mold  28  have temperature control units, which in one form include fluid lines  54 ,  56 , respectively, extending therethrough for circulating heated and/or cooled fluid, such as water, through the molds  12 ,  28  to control the expansion and curing of the liquid polyurethane foam poured into the mold cavity  14  as is commonly known in the art of poured foam. These fluid lines  54 ,  56  may include respective inlets  54 A,  56 A and outlets  56 A,  56 B. It will be understood that the temperature control units may include heating units that may comprise electric heating elements to heat the lower mold  12  and upper mold  28 . 
     The lower mold and upper molds in known mold tool configurations are similar to the lower mold  12  and upper mold  28  but are traditionally formed by casting and machining of metal and then assembling the hinges  42 , clamps  44  and fluid lines  54 ,  56  to complete the mold tool  10 . The present invention relates to a method of forming the inventive mold tool  10  utilizing 3D printing and other method steps to form the lower mold  12  and upper mold  28 . The method is the same for forming either the lower mold  12  or upper mold  28 , therefore, only the method of forming the lower mold  12  will be described further in detail herein relative to the drawings. 
     More specifically, the inventive method includes the step of preparing design tool data with best practices for foam tooling and processing the data with specific build parameters for 3D printing. The lower mold  12  may be 3D printed using an ASA, UV-stable thermoplastic material or the like material in a 3D printer such as model F900 by Stratasys Ltd. One example of the 3D printing data and parameters used in the 3d printer is shown in example  FIG. 5A  for forming a 3D printed lower mold  12  as shown in  FIG. 5B . However, it should be appreciated that the data and parameters may vary as desired for the mold tool and foam part to be manufactured. 
     Referring to  FIGS. 2-4 , the lower mold  12  is 3D printed to form the top mold surface  16 , or A-surface, and the bottom mold surface  18 , or B-surface, extending between the side walls  20 ,  22 , front wall  24 , and back wall  26 . The mold cavity  14  is formed by the 3D printing of thermoplastic material recessed in the top mold surface  16 . Similarly, the upper mold  28  is 3D printed to form the bottom mold surface  32 , or A-surface, and the top mold surface  30 , or B-surface, extending between the side walls  34 ,  36 , front wall  38 , and back wall  40 . The upper mold  28  includes the mold lid  41 , which is formed by the 3D printing of thermoplastic material which projects from the bottom mold surface  32  although it could be recessed as required. 
     Additionally, the fluid (water) lines  54 ,  56  within the interior of the lower mold  12  and upper mold  28  are also 3D printed and formed integral or internal to the respective lower mold  12  or upper mold  28 . As shown in  FIG. 5B , it should be noted that the fluid lines  54 ,  56  are diamond shaped in cross section, as opposed to circular, when 3D printed as part of the mold tool  10  to reduce the amount of support material needed during the 3D printing to support the opening of the fluid lines  54 ,  56 . The inlets  54 A,  56 A and outlets  54 B,  56 B seen in  FIG. 1  may also be formed as separate parts mounted to the exterior of the lower mold  12  and upper mold  28 . 
     After completion of the 3D printing of the lower mold  12 , the lower mold  12  is formed with an interior infill structure  60  that has a porous and open honeycomb type shell as shown in  FIGS. 6A-6E and 7A-7E . The infill structure or honeycomb  60  may also be described as being an open, internal lattice structure provided for strength. The upper mold  28  preferably has the same structure. 
     While these figures illustrate the fluid line  54  formed therein, a similar pattern is provided for the fluid line  56 . As seen in  FIG. 6A , the fluid line  54 / 56  may have a serpentine pattern section  54 - 1 / 56 - 1  formed in one level of the infill structure  60 , and on a next level of  FIG. 6B , a peripheral section  54 - 2 / 56 - 2  joins to opposite ends of the serpentine pattern section  54 - 1 / 56 - 1  and surrounds the mold cavity  14  in the lower mold  12  or surrounds the lid  41  when formed in the upper mold  28 . At the top A-surface  16  of  FIG. 6C , the infill structure  60  is closed by surface material.  FIG. 6D  further shows that the infill structure  60  is formed between the serpentine pattern section  54 - 1  of  FIG. 6A  and the peripheral section  54 - 2  of  FIG. 6B , and then is formed again above the peripheral section as seen in  FIG. 6E .  FIGS. 7A-7E  show similar views from a side perspective. 
     The inventive method further may include the step of sanding the top mold surface  18 , or A-surface, of the mold  12  if desired to achieve a flat and smooth surface in all critical areas. The upper mold  28  may similarly be sanded on the bottom mold surface  32 . Other areas may be sanded as desired such as the mold cavity  14  or lid  41 . Next, the method includes the step of brushing, spraying or otherwise applying a coating layer such as a two part epoxy resin onto the top mold surface  18 , the side walls  20 ,  22 , the front wall  24  and the back wall  26  to coat, seal and close the porous surfaces thereof and prevent bleeding of any liquid polyurethane or other material therethrough that may be used to fill the infill structure. The surface coating of two part epoxy may be of the type available from BJB Enterprises, Inc. as product number TC-1624 A/B. However, it should be appreciated that other types of surface coatings may be used to seal the surfaces without varying from the scope of the invention. 
     After the surfaces are sealed, inserts, taps or mounting bolts may be provided for attachment of the hinges  42  and clamps  44  are set in place in the mold tool  10 . Additionally, fittings and piping may define the inlets  54 A,  56 A and outlets  54 B,  56 B and are provided for connection to the internal fluid lines  54 ,  56  so as to be attached and set in place in the mold tool  12  and in fluid communication with the internal lines  54 ,  56 . It will be understood that hinges and clamps are provided, alternate mechanisms may be provided for this embodiment and the remaining embodiments to accomplish relative movement between the lower mold and upper mold. 
     The invention therefore relates to a method of forming a geometric mold component, which in this embodiment defines the lower mold  12  or the upper mold  28 . The method also includes the step of applying or pouring a filler of an aluminum filled urethane material into the infill structure and the honeycomb cavities thereof that are exposed in the bottom surface  18 , or B-surface, of the lower mold  12  while vibrating the mold  12  to force and evenly distribute the urethane material throughout the mold  12  to fill all of the void space and encapsulate the inserts, taps, bolts and fluid line fittings to the mold  12 . As the aluminum filled urethane material hardens, it fills the infill structure and creates a strong bond and solid mold tool  10 . Additionally, the aluminum particles in the urethane increases the conductivity and strength of the tool. It should be appreciated that the particles may be other than aluminum, such as copper, magnesium, titanium, or the like which increase the conductivity of the urethane material. An example of a suitable filler is a product manufactured as Metal-Kast BC-8010 by BCC Products Inc. However, it should be appreciated that other filler materials may be used without varying from the scope of the invention. 
     Once the filler material has hardened, the method includes cutting the bottom mold surface  18 , or B-surface, of the lower mold  12  with an NC machine or other suitable cutting device to create a finished, flat and even bottom mold surface  18 . The method may further include machining or cutting ribbon vents or attaching autovents into the top mold surface  16 , A-surface, to vent gas during the foam pour expansion and molding process as is commonly known in the art. 
     Once the lower mold  12  and upper mold  28  are formed by the method of the present invention, the upper mold  28  is pivotally attached to the lower mold  12  by the hinges  42 . Finally, the mold tool  10  may be connected to a thermolator and set to a desired temperature of, for example, 165 degrees F. with a tool run temperature of 130-140 degrees F. for forming the poured foam part. The mold tool  10  may now be used as is conventionally known to manufacture a poured foam part. For example, liquid polyurethane foam may be poured into the mold cavity  14  with the mold tool  10  in the open position. The mold tool  10  is placed in the closed position with the upper mold  28  covering the mold cavity  14  and lower mold  12 . The poured foam expands and cures in the mold cavity  14  for a predetermined amount of time at a set temperature and the mold tool  10  is placed in the open position when complete to provide the finished poured foam part. 
       FIG. 8  further illustrates the pattern of the infill structure  60 , which is formed as a 3D lattice formed by crisscrossing surfaces which define openings between the surfaces in the shape of a diamond pattern. This pattern fills the interior space of each mold  12  and  28  but also defines openings that form paths extending through the thickness and width of each mold  12  and  28 . As such, the flowable filler described above can flow through the body of the molds  12  and  28  and eventually harden so that each mold  12  and  28  is solidified through its width and thickness. As seen in  FIG. 8 , the 3D printer may also define bolt holes  61  at multiple locations for mounting purposes or the bolt holes  61  may be drilled out of the solidified and filled bodies of the molds  12  and  28 . 
     Referring to  FIGS. 9A and 9B , an alternate infill structure  60 A may have an alternate pattern as shown in  FIG. 9A , which has a Gyroid lattice structure.  FIG. 9B  shows the gyroid infill structure  60 A in perspective view. Similarly, the gyroid pattern has crisscrossing side surfaces  62  arranged in a wavy pattern and crisscrossing in multiple layers that define a gyroid honeycomb having openings extending through the thickness and width of each mold  12  and  28 . Here again, the infill structure  60 A can be filled with the flowable filler described above to solidify the mold bodies. 
     Referring to  FIGS. 9-12 , an alternate mold tool  65  is shown, which is constructed by the 3D printing in a manner similar to the above-described molds  12  and  28 . The following discussion therefore focuses more on the modifications to the mold tool  65  in comparison to the mold tool  10  with less focus on the common methods for forming the molds using 3D printing. 
     The mold tool  65  comprises a lower mold  66  defining a mold cavity  67  recessed into a top mold surface  68  forming the A-surface. The mold cavity  67  may be formed as an upward opening bowl for receiving poured foam during the mold operation. The lower mold  66  also includes spaced apart side walls  69 ,  70  extending between a front wall  71  and a back wall  72  and surrounding the mold cavity  67 . 
     The mold tool  65  further comprises an upper mold  75 , or lid, pivotally coupled to the lower mold  66  for closing the mold cavity  67  so that the lower mold  66  and  67  are movable relative to each other. The upper mold  75  similarly includes a bottom surface  76  provided as the A-surface for engaging the opposing top mold surface  68  and closing the mold cavity  67 , and includes spaced apart side walls  77 ,  78  extending between a front wall  79  and back wall  80 . A mold lid  81  is formed in the bottom mold surface  76 , preferably projecting therefrom, for mating with the mold cavity  67  although the mold lid  81  may also have at least a portion recessed into the bottom mold surface  76 . 
     The lower mold  66  and upper mold  75  are pivotally joined by one or more pivot hinges  83  so that the upper mold  75  is pivotable relative to the lower mold  66  to swing between an open position providing access to the mold cavity  67 , as shown in  FIGS. 10-11 , and a closed position covering the mold cavity  67 , as shown in  FIG. 12 . One or more clamps  84  are operatively provided for clamping the mold tool  10  in the closed position. 
     To provide rigid support for the hinges  83  and clamp  84 , the lower mold  66  and upper mold  75  comprise rigid, lower and upper main bodies  86  and  87  which are joined with separate the lower and upper mold bodies  88  and  89  that are formed by 3D printing as described above. In more detail, the lower and upper mold bodies  88  and  89  are formed as generally rectangular blocks substantially the same as the lower and upper molds  12  and  28  through 3D printing of the structures and then filling of the honeycomb infill structures  60  as seen in  FIGS. 21A-21B  (upper mold body  89 ) and  FIGS. 21C-21D  (lower mold body  88 ). These lower and upper mold bodies  88  and  89  are then mounted to the main bodies  86  and  87  as an assembly to thereby form the lower mold  66  and upper mold  75  as described herein. 
     In more detail, the lower main body  86  may be formed of a rigid material such as aluminum or other metals and is fixed to the lower mold body  88  such as by fasteners  90  extending through the lower mold body  88 . Rigid, upstanding support flanges  91  may be provided on the front and back of the lower main body  86  to rigidly support the hinges  83  and clamp  84 . As such, the lower mold body  88 , which is 3D printed and filled as described, does not carry the loads of the hinges  83  and clamp  84 . 
     Similarly, the upper main body  87  also may be formed of a rigid material such as aluminum or other metals and is fixed to the upper mold body  89  such as by fasteners  93  extending through the upper mold body  89 . The upper main body  87  rigidly supports the hinges  83  and clamp  84  and also may support a grab handle  94  for opening and closing thereof. Here again, the upper mold body  89 , which is 3D printed and filled as described above, does not carry the loads of the hinges  83  and clamp  84 . This construction has one advantage of transferring loads from the 3D printed material to rigid support structure formed of a more rigid material. 
     This construction also provides additional advantages when heating the molds  66  and  67 , particularly where electric heat will be provided. In this configuration, the lower and upper mold bodies  88  and  89  are not printed or formed with internal cooling channels like the above-described channels  54  and  56 . Rather, the mold bodies  88  and  89  can be molded in a block similar to  FIGS. 8 and 9A-9B  so as to include either a diamond pattern infill structure  60  or the gyroid pattern infill structure  60 A, and then this infill structure  60  or  60 A is filled with a flowable filler such as urethane that then hardens into a solid, rigid block. It will be understood that the term block is not limited to a rectangular or square shape, but other geometric shapes are within the scope of the present invention. As noted, fastener holes  61  may be formed therethrough to receive the fasteners  90  and  93  referenced above so that the lower and upper mold bodies  88  and  89  may be bolted to the lower and upper main bodies  86  and  87 . 
     In this configuration, the lower and upper main bodies  86  and  87  may each have respective temperature control units, which in one form may be internal heating elements extending therethrough, which are controlled by a controller  97  and connected thereto by electrical supply cables  98 . Each main body  86  and  87  may have electrical terminals on the back side thereof or any other side which connect to the internal heating elements. Since the main bodies  86  and  87  are formed of metal, heat can be readily conducted to the lower and upper mold bodies  88  and  89  as needed during the formation of molded foam parts. The main bodies  86  and  87  may be formed with a hollow box-like structure having a hollow interior in which the heating elements are placed and then a heat-conductive filler is provided therein to embed and solidify the heating elements in place. This construction allows elimination of fluid filled heating lines, although fluid lines could alternatively be placed in the hollow interior and then embedded in place by a suitable filler. 
     As such, the main bodies  86  and  87  essentially define heating blocks mountable to the mold bodies  88  and  89 . Further the main bodies  86  and  87  provide structural support to the mold bodies  88  and  89 . In  FIG. 12 , it can be seen that the lower main body  86  need not be exactly the same size as the lower mold body  88 , although they can be provided in the same size. Alternatively, an intermediate plate may be provided such as backing plate  100 , which is shown in  FIGS. 10 and 12  sandwiched between the upper main body  87  and the upper mold body  89 . The backing plate  100  can provide support to a thinner mold body such as upper mold body  89  or help to distribute heat from a heating block across the back face of the upper mold body  89 . 
     Optionally, the main bodies  86  and  87  may be provided in multiple sizes depending upon the size of the respective mold bodies  88  and  89  being mounted thereto. This would allow different mold bodies  88  or  89 , which may have different shapes and designs for the mold cavity  67 , to be matched to an appropriately sized main body  86  or  87 . 
     Here again, the mold bodies  88  and  89  may be formed according to the descriptions provided herein. As noted above, the inventive method includes the step of preparing design tool data with best practices for foam tooling and processing the data with specific build parameters for 3D printing. The mold bodies  88  and  89  may be 3D printed using an ASA, UV-stable thermoplastic material or the like material in a 3D printer such as model F900 by Stratasys Ltd. One example of the 3D printing data and parameters used in the 3D printer has been shown in example  FIG. 5A  for forming a 3D printed mold with the pattern of  FIGS. 1-7 . Alternatively, the gyroid pattern may be preferred and printed according to the 3D printing data and parameters shown in example  FIG. 20 . The resultant mold bodies  88  and  89  are further shown in  FIGS. 21A-21D . However, it should be appreciated that the data and parameters may vary as desired for the mold tool and foam part to be manufactured. 
     In accord with the present description, invention further relates to a method of forming a geometric mold component, which in this embodiment defines the lower mold body  88  or the upper mold body  89 , wherein the lower and upper mold bodies  88  and  89  may be formed by the steps of: 3D printing the honeycomb mold structure to form an open infill structure such as infill structures  60  or  60 A; optionally sanding appropriate mold surfaces as desired; brushing, spraying or otherwise applying a coating layer such as a two part epoxy resin or other sealer onto desired mold surfaces to coat, seal and close the porous surfaces thereof and prevent bleeding of any liquid polyurethane or other material therethrough that may be used to fill the infill structure  60  or  60 A; and applying or pouring a filler of, for example, an aluminum filled urethane material into the infill structure and the honeycomb cavities thereof that are exposed while preferably vibrating the mold to force and evenly distribute the filler material throughout the infill structure  60  or  60 A to fill all of the void space. As the filler hardens, it fills the infill structure  60  or  60 A and creates a strong bond and a solid block. Once the filler material has hardened, the method may include cutting the bottom mold surface with an NC machine or other suitable cutting device to create a finished, flat and even bottom mold surface if desired. The method may further include machining or cutting ribbon vents or attaching autovents into the top mold surfaces, A-surfaces, to vent gas during the foam pour expansion and molding process as is commonly known in the art. 
     Once the mold bodies  88  and  89  are mounted to the main bodies  86  and  87 , the mold tool  65  may now be used as is conventionally known to manufacture a poured foam part. For example, liquid polyurethane foam may be poured into the mold cavity  67  with the mold tool  65  in the open position. The mold tool  65  is placed in the closed position with the upper mold  68  covering the mold cavity  67  and lower mold  66 . The poured foam expands and cures in the mold cavity  67  for a predetermined amount of time at a set temperature and the mold tool  65  is placed in the open position when complete to provide the finished poured foam part. 
     Referring to  FIGS. 13-19 , a second alternate mold tool  105  is shown, which provides an alternate construction for forming lower and upper molds  106  and  107 . The following discussion therefore focuses more on the modifications to the mold tool  105  in comparison to the mold tool  65  with less focus on the common methods used for forming the mold bodies by 3D printing. As discussed below, the lower and upper molds  106  and  107  are formed as mold inserts that inset into corresponding support structure. 
     The lower mold  106  comprises a separable, 3D printed, lower mold insert  108  that defines a mold cavity  109  recessed into a top mold surface  110 . Here again, the mold cavity  109  may be formed as an upward opening bowl for receiving poured foam during the mold operation. The lower mold  106  further includes a lower support panel  111  to which the lower mold insert  108  is mounted. The lower mold  106  also includes a box-like lower main body  113  that defines spaced apart side walls  114 ,  115  extending between a front wall  116  and a back wall  117  and surrounding the mold cavity  109 . 
     The upper mold  107 , or lid, is pivotally coupled to the lower mold  106  by hinges  120  so that the upper mold  107  is pivotable relative to the lower mold  106  to swing between an open position providing access to the mold cavity  109 , as shown in  FIG. 13 , and a closed position covering the mold cavity  109 , as shown in  FIG. 15 . One or more clamps  121  are operatively provided for clamping the mold tool  105  in the closed position, wherein said clamps  121  comprise a clamp latch  121 A and clamp lips  121 B, and are constructed to operate the same as clamps  44 . 
     The upper mold  107  also includes a separable, 3D printed, upper mold insert  122  that defines a mold lid  123  that preferably projects from a bottom mold surface  124 . The bottom mold surface  124  is defined by an upper support panel  125  in which the upper mold insert  122  is mounted. The upper mold  107  also includes a box-like upper main body  126  that defines spaced apart side walls  127 ,  128  extending between a front wall  129  and a back wall  130  and surrounding the upper mold insert  122 . The lower and upper molds  106  and  107  and their respective 3D printed lower and upper mold inserts  108  and  122  are shaped to mate with each other to form molded foam parts in the same manner as the 3D printed lower and upper molds  12  and  28 , and the lower and upper molds  66  and  75  described above. 
     The lower and upper main bodies  113  and  126  may be formed from rigid metal rails that form open box-like lower and upper frames  131  and  132  to provide rigid support for the hinges  120  and clamps  121 . The lower and upper main bodies  113  and  126  also support the lower and upper support panels  111  and  125 , which are mounted thereto by multiple fasteners  133  secured about the panel peripheries. The support panels  111  and  125  in turn support the lower and upper mold inserts  108  and  122  that are formed by 3D printing using the above-described forming method and mounted to their respective support panels  111  and  126  by multiple fasteners secured about the insert peripheries as described further below. 
     In more detail, the lower and upper mold inserts  108  and  122  are formed as thinner and smaller structures in comparison to the lower and upper molds described above. The lower and upper mold inserts  108  and  122  are still formed through 3D printing of with infill structures and then filling of the honeycomb infill structures. These lower and upper mold inserts  108  and  122  are then mounted to the lower and upper main bodies  113  and  126  as an assembly to thereby form the lower mold  106  and upper mold  107 . 
     In more detail as to the upper mold  107  shown in  FIGS. 14-15 , the upper support panel  125  is secured to the upper frame  132  by the fasteners  133  to enclose one side of the upper frame  132 . The upper support panel  126  includes a window  136 , which opens therethrough and is shaped so that the upper mold insert  122  can project from the back panel side through to the front panel side defined by a panel face  125 A. In this configuration, the upper mold insert  122  projects above the panel face  125 A for mating with the lower panel insert  108 . The upper mold insert  122  includes a peripheral flange fitting against the back side of the upper support panel  126  which is secured in place by fasteners. 
     To provide heat to the upper mold  107 , the hollow interior of the upper frame  132  is accessible from the top side as seen in  FIG. 15 , wherein the hollow interior is manufactured with heating units  138  that can be structured as electric heating elements or fluid-circulating heating pipes. The heating unit  138  can be embedded in place by a suitable filler  139  such as a heat-conductive epoxy as seen in  FIGS. 15 and 16 . 
     Next as to the lower mold  106  shown in  FIGS. 17-19 , the lower support panel  111  is secured to the lower frame  131  by the fasteners  133  to enclose one side of the lower frame  131 . The lower support panel  111  includes a window  141 , which opens therethrough and is shaped so that the lower mold insert  108  can project from the back panel side through to the front panel side defined by a panel face  111 A. In this configuration, the lower mold insert  1108  may be flush with or have minimal projection above the panel face  111 A for mating with the upper panel insert  1222 . As seen in  FIG. 18 , the lower mold insert  108  includes a peripheral flange  108 A fitting against the back panel face  111 B of the lower support panel  111  which said flange  108 A is secured in place by fasteners  142  spaced about the periphery of the insert  108 . The upper mold insert  122  has the same flange construction and mounts to the upper support panel  126  in the same manner. 
     Here again, this construction has one advantage of transferring loads from the 3D printed material to rigid support structure formed of a more rigid material. Further, the lower and upper support panels  111  and  125  are readily removable and replaceable so that alternate assemblies of support panels and mold inserts may be mounted in place. This provides the flexibility to construct alternate shaped molds for a variety of molded parts, which can then be mounted to modified upper and lower support panels that mount in place in the same manner as lower and upper support panels  111  and  125 . 
     The mold inserts  108  and  122  and flanges are 3D printed using the forming method disclosed above. In a modified form, the lower and upper mold inserts  108  and  122  can be 3D printed with respective lower and upper insert surfaces  144  and  145  that are closed, wherein the entire surface areas of the lower and upper mold inserts  108  and  122  are solid and enclose a generally hollow interior formed with lattice infill structure such as infill structures  60  and  60 A. This closed construction can be formed by 3D printing. Preferably on these back sides, the lower and upper insert surfaces  144  and  145  may be generally solid on both the top and bottom such as can be seen relative to the lower mold insert surfaces  144  in  FIGS. 17 and 18 . However, the insert surfaces  144  and  145  of the lower and upper mold inserts  108  and  122  are exposed on the back side of their respective lower and upper support panels  111  and  125 . As such, one or more infill ports can be formed in the insert surfaces  144  and  145 . Examples of such infill ports  147  can be seen in  FIG. 18  relative to the lower mold insert  108 . These infill ports  147  are then injected or filled with the filler described above that flows through the infill structure  60 . The filler may be a urethane that then hardens within the infill structure or honeycomb so as to solidify the lower and upper mold inserts  108  and  122 . 
     Next, to provide heat to the lower mold  106 , the hollow interior of the lower frame  131  is accessible from the bottom side as seen in  FIG. 19 , wherein the hollow interior is manufactured with heating units  150  that can be structured as electric heating elements or fluid-circulating heating pipes. The heating unit  150  can be embedded in place by a suitable filler  151  such as a heat-conductive epoxy as seen in  FIG. 19 . 
     In accord with the present description, invention further relates to a method of forming a geometric mold component, which in this embodiment defines the lower mold insert  108  or the upper mold insert  122 , wherein the lower and upper mold inserts  108  and  122  may be formed by the steps of: 3D printing the honeycomb mold structure to form an open infill structure such as infill structures  60  or  60 A; optionally sanding appropriate mold surfaces  144  and  145  as desired; brushing, spraying or otherwise applying a two part epoxy resin or other sealer onto desired mold surfaces to coat, seal and close the porous surfaces thereof and prevent bleeding of any liquid polyurethane or other material therethrough that may be used to fill the infill structure  60  or  60 A; and applying or pouring a filler of, for example, an aluminum filled urethane material into the infill structure and the honeycomb cavities thereof through the infill ports while preferably vibrating the mold to force and evenly distribute the filler material throughout the infill structure  60  or  60 A to fill all of the void space. As the filler hardens, it fills the infill structure  60  or  60 A and creates a strong bond and a solid block. The method may further include machining or cutting ribbon vents or attaching autovents into the top mold surfaces, A-surfaces, to vent gas during the foam pour expansion and molding process as is commonly known in the art. 
     Once the mold inserts  108  and  122  are mounted to the main bodies  113  and  126  by the support panels  111  and  125 , the mold tool  105  may now be used as is conventionally known to manufacture a poured foam part. For example, liquid polyurethane foam may be poured into the mold cavity  109  with the mold tool  105  in the open position. The mold tool  105  is placed in the closed position with the upper mold  107  covering the mold cavity  109  and lower mold  106 . The poured foam expands and cures in the mold cavity  109  for a predetermined amount of time at a set temperature and the mold tool  105  is placed in the open position when complete to provide the finished poured foam part. 
     In view of the foregoing, it will be understood that each lid or cavity described above defines a respective geometric shape that imparts a corresponding shape to the part being molded with the respective mold tool  10 ,  65  or  105 . 
     The invention has been described in an illustrative manner, and it is to be understood that the terminology, which has been used, is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced other than as specifically described.