The present disclosure is directed to tooling formed from a 3D printing tooling scaffold and, particularly, to cast tooling from material extrusion 3D printed scaffolds and a process of forming cast tooling from material extrusion 3D printed scaffolds.
Tooling is used to form parts out of polymer or metal in processes such as injection molding, blow-molding, compression molding, extrusion, vacuum forming, hydroforming, and casting. Tooling typically includes a forming surface, such as a hollowed-out cavity that is a negative form of the part or a raised surface that is a positive form of the part. Tooling is often machined from metal blocks or formed out of wood. Tooling can be simple or complicated, depending on the process in which the tooling is used. For example, in injection molding, tooling may require ejector systems, sprue bushings, cooling lines, moving cores or other features. Increasing complexity increases expense as does the materials and time needed to manufacture the tooling. During part development cycles and in making prototype tooling and parts, the expense of forming a tool for each iteration of the part may be cost prohibitive and the time needed for adjusting the tooling may extend part development cycles.
To address tooling development and product cycle time issues, tooling is sometimes formed by additive manufacturing, where the tooling is formed from a polymer material printed by high speed extrusion, fused deposition modeling, laser sintering, stereolithography, material jetting, and other methods. However, in some applications, these tools may not be mechanically, thermally, or chemically robust enough for the number of molding cycles needed to form enough parts for testing. In addition, additive manufacturing feedstock materials are relatively expensive, and depending on the size and density of the tooling, the tooling may still take days to form. Also, tooling formed by additive manufacturing, in some instances, is not watertight under pressure and additional treatment may be necessary to seal cooling channels and forming surfaces.
While the current tooling processes achieve their intended purpose, there is a need for new and improved tool making methods and tools made by such methods for use in molding parts from formable substances.
According to various aspects, the present disclosure relates to a method forming tooling. The method includes 3D printing a tooling scaffold, wherein the scaffold defines a void volume and a forming surface. The method further includes filling the void volume with casting material and hardening the casting material.
In aspects of the above, the method further includes treating the tooling scaffold prior to filling the void volume with casting material. In aspects, treating the tooling scaffold includes machining the tooling scaffold. In additional or alternative aspects, treating the tooling scaffold includes coating a release agent on the tooling scaffold.
In any of the above aspects, the method further includes applying a magnetic or electrostatic field to the tooling scaffold while filling the void volume with casting material.
In any of the above aspects, the method further includes vibrating the tooling scaffold after filling the void volume with casting material.
In any of the above aspects, the void volume is filled with casting material using a casting method selected from the group consisting of vibration casting, vacuum casting, pressure casting, and centrifugal casting.
In any of the above aspects, hardening the casting material comprises chemically reacting the casting material. In some aspects, the casting material is concrete and chemically reacting the casting material includes hydration. In some aspects, the casting material includes a thermoset and chemically reacting the casting material includes crosslinking the casting material. In some aspects, chemically reacting the casting material includes vulcanization of the casting material.
In any of the above aspects, the method further includes removing the tooling scaffold from the casting material after hardening.
In any of the above aspects, the scaffold further defines cooling lines and the method further comprises introducing cooling or heating fluids or gasses into the cooling lines while hardening the casting material.
In any of the above aspects, the scaffold further defines cooling lines and the method further comprises sealing the cooling lines.
In any of the above aspects, the method includes sealing the forming surface.
In any of the above aspects, the method includes generating a computer numerical control code from a CAD file, wherein the computer numerical control code is used in 3D printing a tooling scaffold. In some aspects, the method further includes merging a plurality of CAD files for generating the computer numerical control code.
According to various aspects, the present disclosure relates tooling formed from a 3D printing scaffold. The tooling includes a 3D printed scaffold, a casting material hardened within the scaffold, and a forming surface defined by the scaffold. In aspects, the tooling is formed according to the above described aspects of a method forming tooling.
In any of the above aspects, the tooling further comprising an auxiliary feature defined by the 3D printing scaffold, wherein the auxiliary feature includes cooling lines.
In any of the above aspects, the 3D printed tooling scaffold includes a plurality of baffles.
The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.
The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. The present disclosure is directed to cast tooling from material extrusion 3D printed scaffolds and a process of forming tooling from material extrusion 3D printed scaffolds. Tooling may include fixtures, jigs, gauges, molds, dies, cutting equipment and patterns. Tooling is used to form parts out of formable substances such as polymer or metal in processes such as injection molding, blow-molding, compression molding, extrusion, vacuum forming, hydroforming, and casting. Tooling typically includes a forming surface, such as a hollowed-out cavity that is a negative form of the part or a raised surface that is a positive form of the part. In general, the process includes forming a tooling scaffold utilizing material extrusion, and in aspects 3D printing, and filling the tooling scaffold to cast the tooling. The cast tooling is, in optional aspects, finished using at least one of the following processes: removing the scaffolding, machining, coating, plating, and polishing. The cast tooling may then be used to form parts from materials such as polymers or metals through molding processes including injection molding, blow-molding, compression molding, roto-molding, composite lay-up, extrusion, vacuum forming, hydroforming, and casting.
References is now made to
At block 104, and with reference to
Only half of the tool base 202, a single plate, is illustrated in
A forming surface 204 is provided in the tool base 202. The forming surface is understood herein as the surface(s) that are used to shape a part. In the illustrated aspect, the forming surface 204 defines a cavity 206, or a negative mold, that is in the shape of a standard tensile test bar, often referred to as a dog bone. In addition, the tool base 202 includes several auxiliary features. In the aspect illustrated in
At block 106 illustrated in
The tooling scaffold 300 includes a scaffold forming surface 304 defining a scaffold cavity 306, which provides the forming surface 204 and cavity 206 of the tooling 200. In addition, the tooling scaffold 300 defines the auxiliary features including a scaffold runner 310, a scaffold injection point 312, and scaffold cooling lines 314, which provide the tooling runner 210, injection point 212, and cooling lines 214 of the tooling 200. The tooling scaffold 300 also defines a scaffold outer perimeter 316, which forms the outer perimeter 216 of the tooling 200. The scaffold outer perimeter 316 of the tooling scaffold 300 is defined by a number of exterior surfaces 318, 320, 322, 324, 326, 328, which form the exterior surfaces 218, 220, 222, 224, 226, 228 of the tool base 202.
In addition, the tooling scaffold 300 defines a void volume 330. The void volume 330 is defined by a number of inner surfaces including inner surfaces 332, 334, 336, 338, 340 as well as the features formed within the tooling scaffold 300 such as the scaffold cooling lines 314 and, while not illustrated, the inner side of the scaffold forming surface 304, scaffold runner 310, injection point 312, etc. The void volume 330 is, in aspects, in the range of 10% to 95% of the total volume defined by the outer perimeter 316 (void or filled volume) of the tooling scaffold 300, including all values and ranges therein, such as 75% to 90%, etc. Void volume is understood herein as volume within the total volume that does not include printed filament.
It should also be appreciated that in alternative aspects where the tooling scaffold 300 may be removed when forming the tooling 200, the inner surfaces 332, 334, 336, 338, 340 and features, such as the inner surfaces of the scaffold forming surface 343′ (see
While the design at blocks 102, 104, or 106 may initially begin as two-dimensional representations of the physical body (i.e., the part to be formed at block 102, the tooling 200 at block 104, or the tooling scaffold 300 at block 105), computer aided design software code is executed to convert the two-dimensional design into a three-dimensional design prior to conversion into a printable version of the design. At block 108, code is executed to convert the three-dimensional design of the tooling scaffold 300 into a computer numerical control (CNC) design or toolpath file, such as G-code to slice the tooling scaffold 300 design into layers and provide code executable by a 3D printer. It should further be appreciated that the tooling 200, including the tool base 202, the features of the forming surface 204, and the auxiliary features, including the cooling lines 214, runner 210, injection point 212, etc., may be designed in one or more CAD files. If designed in multiple CAD files, the features may be merged into a single CAD file before proceeding. Similarly, the tooling scaffold 300 tool base 302, and the various features including the scaffold forming surface 304 and the auxiliary features, including the scaffold cooling lines 314, scaffold runner 310, scaffold injection point 312, etc. may be provided in one or more CAD files. If designed in multiple CAD files, the features may be merged into a single file before or after converting the CAD file into computer numerical code software for printing, described further below.
At block 110, and with reference to
In additional aspects, the filament includes additives such as, but not limited to: fibers including carbon fiber, glass fiber, metal fibers, mineral fibers, or fibers of a different polymer having relatively higher melting points than that of the polymer forming the filament; and particles, powders or flakes including glass, metal, cellulose, mineral, carbon, or carbon nanotubes. In aspects, the additives include electromagnetic susceptible materials that heat upon the application of radio frequency including, for example, ferrous metals or carbon nanotubes in the forms described above. The fibers exhibit a particle size in the range of 1 micrometer to 100 micrometers, including all values and ranges therein and the particles, powders or flakes exhibit a size of 100 micrometers or less including all values and ranges therein, including nanoparticles having a particle length of less than 1.0 micrometer or less, including all values and ranges between 10 nanometers and 1 micrometer. Such additives, in aspects, are dispersed in the filament 402 and, in other aspects, are provided in a coating on the filament core, wherein the coating includes the same polymer or a different polymer than the filament core. The additives are present in the range of 0.1% to 90% of the total weight of the filament, including all values and ranges therein.
In further aspects, other additives are included, such as pigments, dispersants, surface modifiers, processing aids such as viscosity reducers or release agents, and flame-retardant agents, such as a vinyl modified siloxane, organo-modified siloxanes. These additives are, in aspects, dispersed through the filament, or, in alternative aspects, localized in either the filament core or filament coating. The additives are present in the range of 0. 1 to 25% of the total weight of the filament, including all values and ranges therein.
The filament 402 is then deposited on a support surface 406 layer 408 by layer 408+n in accordance with the computer numerical code to form a tooling scaffold 400. As illustrated, two passes of filament 402 are used create the wall 410 and two passes of filament 402 are used to create a scaffold cooling line 412. It should be appreciated that the number of passes of filament 402 used to form each feature of the tooling scaffold 400 may vary depending factors such as whether the tooling scaffolding 400 will remain with the tooling 200, the mechanical properties required to support the features of the tooling scaffold 300, and the mechanical properties required from each feature during use, if the tooling scaffold 400 is not removed. In aspects, in the range of 1 to 10 passes may be used to form tooling scaffold features, including all values and ranges therein, such as 1 to 2 passes, 3 to 4 passes, etc. Referring to
The casting material 552 includes materials that are flowable and can be hardened, cured, or crosslinked, such as concrete, ceramics, thermoplastics, foam, gels such as xerogels or gelled thermosets, low melting point metals, eutectic alloys, and thermoset polymers.
Thermoset polymers include, for example, epoxy, urethanes, acrylic resins, polyesters, vinyl esters, phenolics, amino resins, furan resins, benzoxazines, and silicones. The casting material 552, in aspects, includes fillers, such as in the form of fibers, powders, particles or flakes, to relatively increase strength, hardness, thermal conductivity, lubricity, dimensional stability, machinability or combination thereof. In an aspect, the fillers include fillers susceptible to a magnetic field, electric field, or an electromagnetic field, to influence the orientation of the fillers before or during curing. In a further aspect, conductive fillers, such as metal particles, metal fibers, carbon particles, carbon nanotubes, or electromagnetic susceptors are present in the casting material 552 in an amount sufficient to provide conduction of a current, heat, or both, through the castable material 552 after curing. In aspects, these susceptible fillers may also aid in the curing process by enabling heating of the casting material with electric currents or electromagnetic energy including DC currents, radio frequency, microwave, and infrared heat.
Fibrous fillers used in casting material 552 include carbon fiber, glass fiber, metal fibers, mineral fibers, or fibers of different polymer materials having relatively higher melting points than that of the polymer forming the filament. Fibrous fillers exhibit a length in the range of 1 micrometer to 10 millimeters, including all values and ranges therein, such as in the range of 1 micrometer to 100 micrometers, 100 micrometers to 3 millimeters, etc. Powders, particles, or flake include glass, metal, cellulose, mineral, fluoropolymer, graphite, carbon, molybdenum disulfide, and ceramics such as boron nitride and aluminum nitride, as well as carbon nanotubes, wherein the powders, particles, flakes, or nanotubes have, in some aspects, a particle size of 100 micrometers or less, including nanoparticles having a particle length of less than 1. 0 micrometer. In aspects, the fillers are present in an amount of 1 percent to 95 percent of the total weight of the casting material 552, including all values and ranges therein, such as 25 percent to 90 percent, 20 percent to 50 percent, etc.
In aspects, the tooling scaffold 502 is treated prior to the introduction of the casting material 552, such as being coated in release agents or machined prior to adding the casting material 552. In additional aspects, a treatment is applied to the casting material 552 as it fills the tooling scaffold 502 or once it has been added to the tooling scaffold 502. For example, a magnetic or electrostatic field is applied to the casting material 1552 as it fills the tooling scaffold 502 or after filling the tooling scaffold 502 to orient the filler particles susceptible to such fields within the casting material 552. In further aspects, the tooling scaffold 502 is treated after adding the casting material 552, such as by vibrating the tooling scaffold 502 to assist in settling the casting material 552 and reducing air bubbles in the casting material 552 prior to hardening. In aspects, casting methods including vibration casting, vacuum casting, pressure casting, or centrifugal casting are employed herein to assist in filling the scaffold with full density, eliminating air voids, or working with high viscosity or thixotropic casting materials.
The casting material 552 hardens to form a solidified shape. In aspects, hardening is caused by a chemical reaction in the casting material, such as hydration, curing, vulcanization, or irradiation. In aspects including concrete, hardening is due to hydration, where water in the concrete mix forms chemical bonds with the cement in the concrete mix. In aspects including thermosetting polymers, hardening occurs through the crosslinking of polymer chains initiated by the addition of crosslinking agents, heat, pressure, change in pH, irradiation, or a combination thereof. Thermoplastic polymers, in aspects, are also useable as casting materials 552 and cross-linked upon exposure to irradiation such as an electron beam, gamma radiation, or light in the UV electromagnetic range.
It should be appreciated that in some aspects, such as the aspect illustrated in
At block 114, and with reference again to
At block 116 of
The cast tooling 200, 500, 600 is used to form parts, in processes such as injection molding, blow-molding, compression molding, roto-molding, composite lay-up, extrusion, vacuum forming, hydroforming, and casting. As noted above, the tooling includes, for example, a mold, die, jig, pattern, or fixture. In aspects, the parts are formed from thermoplastics, thermosets, woven fabrics, non-woven fabrics, or metal of various forms including sheets, pipes, or other profiles. For example, the cast tooling 500 of
The cast tooling and method of forming cast tooling from material extrusion 3D printed scaffolds of the present disclosure offer several advantages. These advantages may include a relative reduction tooling mass and density prior to adding the casting material. These advantages may further include a relative reduction in time to print tooling and form a 3D printed tooling as compared to 3D printed tooling that is in filled with printed filament. These advantages may further include a relative reduction in cost the 3D printed portion of the tooling as compared to 3D printed tooling including 3D printed infill. These advantages may yet further include the ability to utilize relatively lower performance, less costly resins, as the 3D printed portion of the tooling is supported by relatively higher performance casting materials. These advantages may also include the reduction in the number of processing steps as the filling the tooling scaffold and sealing cooling lines can occur in a single step.
The description of the present disclosure is merely exemplary in nature and variations that do not depart from the gist of the present disclosure are intended to be within the scope of the present disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the present disclosure.
The present application claims the benefit of the filing date of U.S. Provisional Application 63/036,707, filed on Jun. 9, 2020, and incorporates the teaching herein by reference.
Filing Document | Filing Date | Country | Kind |
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PCT/US21/36150 | 6/7/2021 | WO |
Number | Date | Country | |
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63036707 | Jun 2020 | US |