Method of producing patterns, molds, and related products

Abstract

To provide a method for producing parts by a lamination technique.SOLUTION: A method for manufacturing parts includes: taking a porous material to form a plurality of individual layer segments from a sheet by using a computer numerical control (CNC) router; forming a plurality of layers with the plurality of individual layer segments; fastening the plurality of layers in a manner to form a part of a shape including a hollow inner part; supplying a thermosetting material adaptable to a porous part of the porous material to a porous material of a part; and removing a porous material on an outer face of a part by using the CNC router so as to form a part having a continuous face and a hollow inner part.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] Aspects of the present disclosure relate to apparatus and methods for manufacturing components. In some instances, aspects of the present disclosure relate to methods for manufacturing components (e.g., patterns, molds, and / or similar products) by techniques or processes similar to 3D printing manufacturing processes, which are additive but do not use 3D printers and use low-cost filler materials. [Background technology]

[0002] Additive manufacturing techniques and processes involve building up one or more materials, as opposed to subtractive manufacturing methods, to create net-shape or near-net-shape (NNS) objects. While "additive manufacturing" is an industry-standard term (ASTM F2792), additive manufacturing encompasses a variety of manufacturing and prototyping techniques known by various names, including freeform fabrication, 3D printing, and rapid prototyping / tooling. A relatively new additive manufacturing technique uses large-scale 3D printing machines to produce very large parts, molds, patterns, and the like. These items can be made from fiber-reinforced thermoplastic materials. One method of producing these items utilizes a polymer extruder, which creates a bead of molten thermoplastic material that is added to the part, producing one layer at a time. These layers are then flattened and formed into wide beads using devices such as backing plates and rollers during the build-up process. Using this method, known as 3D printing or additive manufacturing, parts are made slightly larger than the desired final part. After the part cools and hardens, it is machined to its final size and shape. After machining, the part may be formed as a shell of a specific thickness with the desired size and shape. Summary of the Invention [Problem to be solved by the invention]

[0003] Although the above-described processes are useful, they also introduce problems that limit their suitability in certain environments. For example, thermoplastic materials can shrink or contract as they cool from printing temperatures to ambient or room temperatures. This shrinkage is generally not uniform in all directions and, in at least some cases, must be taken into account when developing the part's geometry after printing, complicating the design and manufacturing process. Furthermore, because the material is soft when printed and is affected by gravity, there are limitations on the maximum angle at which the part's walls can be printed. Thus, creating hollow parts with solid vertices can require internal support structures or other types of additional support structures used during printing, which are printed separately and increase costs. This further complicates manufacturing operations. Additionally, the materials and equipment typically used in this process are expensive, limiting the number of applications for which it is suitable.

[0004] An exemplary filler material, or supplement, used in thermoplastic additive manufacturing processes is carbon fiber. This filler material, added to the base polymer, tends to stiffen and strengthen the underlying polymer and minimize warping that might otherwise occur as the part cools. However, carbon fiber is expensive and therefore increases the cost of products produced using this process. This increased cost may limit its potential use in applications where the value of the produced pieces justifies the cost. Low-cost reinforcing materials, such as wood fiber, may be unsuitable for use with at least some manufacturing equipment. For at least some parts or base materials, there may be a maximum amount of filler material that can be added to the base material (e.g., thermoplastic material). Beyond this maximum amount of filler material, changes in the filler material's properties may adversely affect the ability of the filled thermoplastic material to be processed in an additive manufacturing system, such as a 3D printing device. Even if a 3D printing device or other additive manufacturing system is capable of using highly filled materials, the equipment may introduce high costs that make manufacturing such parts impractical. [Means for solving the problem]

[0005] Aspects of the present disclosure relate to methods and apparatus for, for example, manufacturing components by additive techniques. Each aspect disclosed herein includes one or more of the features described in connection with any other disclosed aspect. Some aspects of the present disclosure are useful in processes for forming patterns, molds, and other articles or products using additive methods. In some aspects, the additive methods are comparable to 3D printing or other additive manufacturing methods, although they use techniques that can be used with relatively low-cost filler materials, at least in some circumstances. Some aspects of the present disclosure address the above-mentioned and / or other problems in the art.

[0006] In one aspect, an additive manufacturing method includes removing material from a sheet to form multiple segments of individual layers, arranging at least two segments of the first layer that form a first portion of the exterior surface of the part adjacent to one another at the same height to form a first layer having a hollow interior, and arranging at least one segment of a second layer that forms a second portion of the exterior surface of the part over the at least two segments of the first layer to form a second layer having a hollow interior. The additive manufacturing method may include attaching the first layer to the second layer, and removing portions of material from the first layer and the second layer to form a part having a continuous surface extending along the first layer and the second layer.

[0007] In another aspect, a method of manufacturing a part includes removing porous material from a sheet using a CNC router to form multiple segments of individual layers, forming multiple layers using the multiple segments of individual layers, and bonding the multiple layers together to form a shaped part having a hollow interior. Such a method may include infusing the porous material of the part with a thermosetting material (which may be crosslinked, such as with a catalyst), and removing portions of material from an exterior surface of the part using the CNC router to form a part having a continuous surface and a hollow interior, where the thermosetting material can conform to the porosity of the porous material by using a vacuum pump, by applying pressure, by dipping the part into the thermosetting material, or by spraying the part with the thermosetting material.

[0008] In some aspects, the parts are manufactured using additive processes that facilitate the production of polymer-based products with higher amounts of low-cost filler materials, especially compared to the polymer content of the product, and that also involve the use of lower-cost equipment, especially compared to extrusion-based thermoplastic additive manufacturing processes.

[0009] In some aspects, the processes and apparatus described herein may employ a filler material to produce part structure. A polymer material is added to the filler material (or filler materials) that forms the majority of the finished part (e.g., greater than 75% by volume and / or weight), as opposed to a process in which the filler material is added to the polymer that forms the majority of the finished part. For example, this process may include producing part structure from the filler material itself, and may further include trimming the filler material, if necessary. Subsequently, the filler material is infused with a thermosetting polymer by supplying the thermosetting polymer in liquid form to the filler material. The thermosetting polymer or other suitable material may be cured after being supplied in liquid form. The cured filled polymer mixture may impart improved physical properties to the part.

[0010] The accompanying drawings, which incorporate or constitute an integral part of the present disclosure, illustrate exemplary aspects of the present disclosure and, together with the detailed description, serve to explain the principles of the present disclosure. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view of an exemplary CNC machine operable to profile multiple layers of material in accordance with aspects of the present disclosure. [Figure 2] FIG. 1 is a plan view of an exemplary bottom or first layer assembled with a portion of a second layer of an exemplary product. [Figure 3] 1 is a plan view of an example portion of a layer of a part having an identifier (e.g., a number or letter) machined into the material of the portion of the part. [Figure 4A] FIG. 10 is a top view of an assembled example second layer aligned with a first layer. [Figure 4B] FIG. 4B is an exploded view of the exemplary first and second layers shown in FIG. 4A. [Figure 5A] FIG. 1 is a top view of an exemplary fully assembled near net shape part. [Figure 5B] FIG. 5B is a front view of the component shown in FIG. 5A. [Figure 6A] FIG. 1 is a perspective view of an example part after it has been machined to a desired shape and size. [Figure 6B] FIG. 6B is a front view of the example component of FIG. 6A. [Figure 7] FIG. 2 is a partially simplified diagram of an exemplary component and internal support. [Figure 8] FIG. 1 is a perspective view of a part having a sealed bottom surface during resin dispensing. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present disclosure is directed, among other things, to methods and apparatus for manufacturing components by layering techniques. In particular, the methods and apparatus described herein are directed to processes for forming patterns, molds, and other parts or products using layering techniques.

[0013] As shown in FIG. 1 , the manufacturing machine, such as a CNC router (router) 11, is configured to controllably remove material from a workpiece. The CNC router 11 is part of a manufacturing system that includes a control unit, or controller 100, configured to generate instructions, such as to operate a plurality of servo motors and position the tools of the CNC router 11. The CNC router 11 is operable to remove material from a variety of different materials. For example, the CNC router 11 is configured to position and operate a cutting tool in response to commands generated by the controller 100. The CNC router 11 may be any suitable machine for removing material with a cutting tool and modifying the surface of a material, such as a three-axis router (e.g., a machine configured to position a cutting tool in three degrees of freedom), a five-axis router (e.g., a machine configured to position a cutting tool in five degrees of freedom), or an additive manufacturing device having a printing head in addition to a machining head.

[0014] Exemplary components manufactured by the processes described herein are formed, at least in part, from a porous material. Exemplary suitable porous materials include medium-density fiberboard (MDF). The individual sections for the component may include, in place of or in addition to MDF, Plexiglas, ultra-high molecular weight (UHMW) plastic (e.g., UHMW polyethylene), polyvinyl chloride (PVC), plastic, plywood, drywall, or aluminum.

[0015] The part structure may be formed by assembling multiple layers. Each layer may include one or more segments 13. For example, multiple layers may be stacked one on top of the other, as described below, to form a desired shape. In the exemplary configuration shown in FIGS. 2-8, when the part is assembled, it forms a hollow cone shape. The actual geometry of a typical part that can be produced using this process can vary widely, both in shape and size. For clarity, a cone shape is described herein. However, it is expected that parts produced using the methods described herein will be significantly more complex than a simple cone. In this example, each layer includes or consists of segments (beads) of a specific desired thickness and width, so that the final structure resembles structures commonly produced using current thermoplastic additive manufacturing techniques.

[0016] The process for manufacturing a part involves producing a plurality of individual pieces, or segments 13, which are subsequently assembled together. For example, each layer, including segments (beads) of a predetermined or known width, is formed from segments 13 cut from sheets 12 of a suitable material, such as medium density fiberboard (MDF), low density fiberboard (LDF), or synthetic plastic foam. As shown in FIG. 1, the segments 13 for a single part are first formed into multiple sheets 12. As shown in FIG. 1, cutting or machining of the sheets 12 is performed with a suitable machine, such as a CNC router 11. The CNC router 11 cuts or separates the individual segments 13 belonging to the same layer from one another. In the example shown in FIG. 1, each segment 13 forms an open (e.g., semicircular or arc-shaped) structure. Additionally or alternatively, one or more segments 13 may be sized and shaped for use in forming the entire layer, thus forming a single closed loop structure (e.g., a closed circle, oval, square, rectangular, or irregular shape). Additionally, when forming a final part having a hollow interior, as described below, one or more of the multiple segments 13 may be nested (e.g., positioned inside an arc), as shown in Figure 1. Nesting multiple segments 13 within a single sheet of material 12 improves material utilization and reduces costs.

[0017] As shown in FIG. 2 , multiple individual segments (pieces) 13 formed by removing multiple materials from a sheet 12 are bonded together to form one layer of a part, e.g., a portion of a cone. A seam or joint 14 is formed at the interface between a pair of opposing individual segments 13. In the exemplary assembly shown in FIG. 2 , an upper, or second, layer 15 containing one segment (piece) 13 is continuous with and supported on the top surface of the multiple pieces 13 of a lower, or first, layer 16. In some aspects, the joints 14 are formed by the interface where the individual segments (beads) of a single layer abut one another. In some aspects, each joint 14 may be offset from the joints 14 formed in the adjacent layers (the layer immediately above and / or below). This offset, e.g., staggering, improves the strength of the part.

[0018] In the exemplary configuration shown in FIG. 2 , two arc-shaped segments 13 are assembled together, so that the joints 14 in the first layer 16 are circumferentially spaced 180 degrees apart. However, 120-degree intervals, 90-degree intervals, or irregular intervals may be used depending on the number and shape of the segments 13. Each joint 14 in a first layer (e.g., layer 16) may be offset from each joint 14 in a second layer (e.g., layer 15) so that the joints 14 in a given layer do not overlap any joints 14 formed by adjacent layers. In the example shown in FIG. 2 , the joints 14 are formed by abutment joints between the segments 13. Each abutment joint 14 in the first layer 16 is offset 90 degrees from one or more abutment joints 14 in the second layer 15 (the locations of the abutment joints 14 formed in the second layer 15 are fully illustrated in FIG. 2 ).

[0019] Multiple segments 13 may be employed to manufacture relatively large structures, whereby the finished part, as described below, is larger than the CNC router 11. Because forming a large structure involves the production of a large number of components (e.g., segments 13), it is preferable to facilitate identification and assembly of these segments 13. For example, the CNC router 11 or other suitable machining system may etch or otherwise form marks 17 into the surface of each segment 13. Each mark 17 may indicate the layer number (e.g., 1, 2, 3, 4) and / or the position within a particular layer (e.g., A, B, C, left, right, top, bottom) of the segment 13, as shown in FIG. 3. In some aspects, removing a portion of material from each segment 13 to form the marks 17 allows the segments 13 to be identified, eliminating the need to label and then remove the mark, which may interfere with assembly.

[0020] As shown in FIGS. 3, 4A, and 4B, one or more segments 13 include features configured to facilitate assembly of multiple segments 13 into a near-net-shape part. For example, multiple dowel holes 18 are machined or otherwise formed in each layer (e.g., one or more segments 13 of each layer) to facilitate aligning these layers (segments) with one another. As shown in FIGS. 4A and 4B, each dowel hole 18 penetrates the top and bottom surfaces of a particular segment 13. The multiple dowel holes 18 are used to align each layer with the layer above and / or below it. As shown in FIG. 4B, mechanical fasteners, such as multiple dowel pins 19, are inserted into two or more aligned dowel holes 18. The dowel pins 19 and dowel holes 18 are configured to facilitate permanent assembly or attachment of multiple layers, each layer including one or more segments 13. After assembly, each layer is permanently attached to one or more other layers using adhesives, bonding agents, mechanical fasteners, or a combination thereof. When mechanical fasteners are used, the layers do not need to be compatible with adhesive bonding techniques. Thus, when mechanical fasteners are used, the entire part may be adhesive-free.

[0021] 5A and 5B show near-net-shape part or object 20 when each of the multiple layers is assembled and attached to one another. When object 20 is assembled, object 20 has a hollow interior formed by the inner diameter surfaces of multiple arcuate segments 13 (FIGS. 1-4A). When object 20 is assembled, the outer surface of object 20 has a stepped shape. Object 20 generally forms a conical or frusto-conical shape.

[0022] 6A and 6B illustrate an exemplary part or conical mold 21 formed by processing a near-net-shape object 20. The conical mold 21 may be formed by machining the exterior surface of the part or object 20 to the desired final dimension and shape, e.g., the conical mold 21. In some aspects, this machining may be performed by a CNC machine, e.g., a CNC router 11. The router 11, in response to instructions generated by the controller 100, removes portions of material from the exterior surface of the object 20 to form a continuous surface 30 that extends along at least the first layer 16 and the second layer 15. As shown in FIGS. 6A and 6B, the machined continuous surface 30 may extend from the bottom end of the mold 21 to the top end of the conical mold 21. Also shown in FIGS. 6A and 6B, the interior of the conical mold 21, which has not been machined to form a smooth surface, remains a stepped surface formed by the multiple segments 13 of each layer, including the first layer 16 and the second layer 15. The conical mold 21 (or any other part formed by the processes described herein) may be larger than the CNC router 11. For example, the mold 21 may have a height greater than the height of the CNC router 11, or a length greater than the length of the CNC router 11, or a width greater than the width of the CNC router 11, or any combination thereof. By forming such large parts with hollow interiors, the amount of material required to make such parts can be significantly reduced.

[0023] 7, a process for manufacturing a part, e.g., a conical mold 21 or other mold, includes creating and enclosing a support structure, such as support 22. Support 22 has a shape that at least partially conforms to the shape and interior of conical mold 21. Support 22 may have, for example, a stepped exterior shape that conforms to the stepped shape of the hollow interior of conical mold 21. Each step conforms to a respective layer of mold 21, e.g., first layer 16 and second layer 15.

[0024] One or more internal supports 22 are added to the interior of the conical mold 21 to provide mechanical support for the structure of the conical mold 21. This mechanical support is advantageous while the mold 21 is in use during the molding process. However, if desired, the supports 22 may be placed within the mold 21 prior to machining the continuous surface 30. The supports 22 are formed of a suitable material, such as wood. The supports 22 may be temporarily or permanently attached to the mold 21 using adhesives, bonding agents, mechanical fasteners, or a combination thereof. Although a single support 22 is secured within the mold 21, multiple supports 22 may be manufactured and attached to the mold 21.

[0025] After machining, the mold 21, with or without the support 22, is suitable for a variety of applications. For example, the mold 21 or other structures manufactured according to aspects of the present disclosure can be used as a mold for forming fiberglass components. The mold 21 is also useful as a component for a CNC router, serving as a fastener for securing plastic molded parts as they are machined by the CNC router 11. Various porous materials (sheets) 12, such as MDF, are suitable for this process, despite being less strong, durable, and wear-resistant than conventional materials. In order to use the mold 21 in one or more of the above-mentioned applications, it may be desirable to enhance the physical properties of the mold 21. For example, if a majority of the material in the mold 21 (e.g., greater than 50%, greater than 75%, or greater than 90% by volume and / or weight) is porous material (sheet) 12, such as MDF, the inherent porosity of the material can be utilized to enhance the physical properties of the final product.

[0026] For example, it may be desirable to apply a reinforcing material to the mold 21. The process for manufacturing the mold 21 may include performing one or more steps to reinforce the mold 21, such as applying a vacuum to the inside of the part using a vacuum pump 24, as shown in FIG. 8. Other methods for reinforcing the mold 21 include applying pressure to force the reinforcing material (e.g., a thermosetting material) into the mold 21, dipping the mold 21 into the thermosetting material, or spraying the mold 21 with the thermosetting material, etc. If the thickness of the outer wall of the part is sufficiently thin, when the pump 24 is so applied to the mold 21 or other part, air will infiltrate the part across the entire surface of the part (e.g., depending on the width of the segments (beads) or layers used in the process).

[0027] To effectively apply a reinforcing material via vacuum 24 to reinforce a part such as mold 21, the base or bottom surface 23 of the part opposite the narrow portion or end of mold 21 can be sealed and a high-flow vacuum pump 24 can be connected to part 21 via bottom surface 23. As shown in FIG. 8 , vacuum pump 24 is attached to part 21 and used to evacuate air from inside sealed part 21. In at least some applications, the volume of air evacuated by vacuum pump 24 is greater than the volume of air flowing from the surface of the built part, so that the vacuum level and resulting air flow from the surface of the part are maintained despite air infiltration from the surface.

[0028] The attached vacuum pump 24 may be operated to actively evacuate air from the interior of the mold 21 while supplying a thin, low-viscosity resin 25, such as an epoxy, to the surface of the part, e.g., the continuous surface 30, as shown in FIG. 8 . The vacuum applied to the interior of the part creates an airflow through the part (e.g., from the exterior of the part through the continuous surface 30 to the interior of the part), drawing the liquid resin 25 into the material's structure. As the resin 25 is drawn into the pores of the material, the airflow gradually decreases in areas where the resin 25 has been infused throughout all or almost all of the thickness of the part. This has the effect of increasing the airflow in areas where the resin 25 has not yet been fully infused. By supplying resin to these areas, the entire part 21 is eventually infused with the resin 25. Once the entire part 21 is infused with the resin 25, the vacuum pump 24 is stopped, and the resin 25 is allowed to fully cure and harden. As a result, the strength and physical properties of the part 21 are improved.

[0029] In an alternative process, multiple layers of part 21 are provisionally fastened together with dowel pins 19 or another suitable method to form a near-net shape. A seal is then formed on bottom surface 23 of part 21. A vacuum is then applied to part 21 by vacuum pump 24, causing air to flow from the outside of part 21 to the inside and through the part. A layer of resin 25 is then applied to part 21. As resin 25 is drawn into part 21, it gradually seals these areas, increasing the vacuum in other areas of part 21 and drawing resin 25 into these unsealed areas. Once part 21 is fully infused with resin 25 and resin 25 is fully cured, resin 25 forms a bond that permanently holds the multiple layers together. This infusion of resin 25 can occur prior to machining, for example, when object 20 has a shape corresponding to FIGS. 5A and 5B. Once infused with resin 25, object 20 can be machined to the desired final size and shape and used in a wide range of applications. One exemplary application for mold 21 formed in this manner is for use in an autoclave. Because all layers of mold 21 are permanently bonded together by resin 25, autoclave use is appropriate.

[0030] As an alternative to using a vacuum to inject the resin into the assembled structure, a liquid thermosetting material may be used. The concentration of a suitable liquid thermosetting material should be thin enough to penetrate the open pores of the material forming the structure of mold 21 through capillary action, whereby the liquid thermosetting material penetrates into the structure of mold 21. This capillary action should be sufficient to inject the resin without the need for additional forces such as vacuum or pressure.

[0031] As an alternative to using a vacuum to inject resin into the assembled structure, it is also possible to use a liquid thermosetting material that is thin enough to penetrate the open pores of the particular structural material utilized via natural capillary action, in which case the liquid material will fully penetrate into the structure without the need for additional external forces such as vacuum or pressure.

[0032] Different resin 25 formulations may be combined with different substrates (e.g., sheet 12 materials) to achieve desired properties. When an object is formed according to one of the above-described embodiments, a particular resin formulation and / or substrate material can be selected to achieve desired physical properties useful for one or more specific applications of the finished part formed by assembling and modifying the object. The resulting part 21 is a low-cost, highly filled polymer part with many desired properties.

[0033] It will be apparent from the foregoing detailed description that there are numerous variations, adaptations, and modifications of the present disclosure that are within the purview of one skilled in the art to which the above disclosure pertains. However, it is intended that all such variations that do not depart from the spirit of the present disclosure be considered within the scope of the present invention when included within the scope of the appended claims.

Claims

1. 1. A method of manufacturing a part, comprising: removing porous material from the sheet using a computer numerically controlled (CNC) router to form a plurality of individual layer segments; forming a plurality of layers from a plurality of individual layer segments; bonding the layers together to form a shaped part having a hollow interior; injecting a thermosetting material into the porous material of the part, the thermosetting material being compatible with the porosity of the porous material; and removing porous material from an exterior surface of the part using a CNC router to form a part having a continuous surface and a hollow interior.

2. The method of claim 1 , wherein the layers are permanently attached to one another by a thermosetting material.

3. 10. The method of claim 1, further comprising using a CNC router to remove the porous material of at least one of the plurality of individual layer segments to form a mark indicating the layer number, position, or both.

4. The method of claim 1 , wherein the first and second layers include aligned dowel holes such that the dowels extend at least partially through the first and second layers.

5. The method of claim 1 , wherein the hollow interior includes a stepped surface.

6. The hollow interior extends from the open end to the closed end; The method of claim 1 , further comprising disposing a physical support within the hollow interior that extends from the closed end to the open end.

7. The method of claim 6 , wherein the thermosetting material is applied after removing porous material from the exterior surface of the component.

8. The method of claim 1 , wherein the part is a mold or a fixture of a CNC router.

9. The method of claim 1 , wherein the plurality of individual ply segments are arc-shaped segments that form a plurality of joints.

10. The method of claim 1 , wherein the part is larger than the CNC router.

11. The method of claim 1 , wherein bonding multiple layers together to form a part having a shape with a hollow interior includes forming a part in the shape of a cone.

12. The method of claim 1 , wherein removing the porous material from the exterior surface of the component comprises removing the porous material from two or more layers of the plurality of layers.

13. The method of claim 1 , further comprising sealing the open end of the hollow interior before injecting the thermosetting material into the porous material of the part.

14. The method of claim 1 , wherein the thermosetting material is a resin.

15. 10. The method of claim 1, wherein applying the thermosetting material to the part is performed using a vacuum pump, by applying pressure to the part, by immersing the part in the thermosetting material, or by spraying the part with the thermosetting material.

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