Building panel arrangement incorporating a heating / cooling system for additive manufacturing

Abstract

A build plate assembly configured for use with an additive manufacturing machine. The assembly comprises a build plate that defines a reservoir extending through the build plate. An insert sits within the reservoir and is movable within it. The insert includes a build surface configured to support a product built upon it by the additive manufacturing machine. The insert sits on a base with a heating element configured to heat the insert. The insert is configured to expand within the reservoir when heated by the heating element. The reservoir is configured to accommodate this expansion.

Description

INTRODUCTION

[0001] The information in this section is intended to provide a general context for the disclosure. Work by the presently named inventors, to the extent described in this section, as well as aspects of the description that may not be prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

[0002] The present disclosure relates to a build plate assembly for an additive manufacturing machine.

[0003] Additive manufacturing, also known as 3D printing, is a manufacturing process in which objects are created by depositing material layer by layer onto a build plate. Unlike traditional subtractive manufacturing processes, where material is carved from a solid block to create the desired shape, additive manufacturing builds an object on the build plate. The material from each layer is fused together to create a cohesive product. This process typically generates heat, which is transferred to the build plate. SUMMARY

[0004] The present disclosure includes, in various features, a build plate assembly configured for use with an additive manufacturing machine. The build plate assembly includes a build plate defining a container extending through the build plate. An insert sits within the container and is movable within the container. The insert includes a build surface configured to support a product built thereon by the additive manufacturing machine. The insert sits on a base having a heating element configured to heat the insert. The insert is configured to expand within the container when heated by the heating element. The container is configured to accommodate the expansion.

[0005] In other features, the base contains a heat-conducting material.

[0006] In further features, the heating element comprises heating rods and / or heating coils designed to conduct electricity.

[0007] In other features, the base includes a cooling element configured to cool the base and insert.

[0008] In further features, the cooling element includes cooling lines configured to carry a cooled coolant through the base.

[0009] In further features, the cooling element includes cooling pins and / or Peltier coolers.

[0010] In other features, the base directly touches the insert.

[0011] In further features, the present disclosure provides an insulator defining an insulator receptacle, wherein the base sits within the insulator receptacle.

[0012] In further features, the insulator and the base form or define a gap between them.

[0013] In further features, there is a support plate on one side of the insulator opposite the building plate, which limits part of the insulator holder.

[0014] In further features, a biasing member is in contact with the base to bias the base and insert into an outward position.

[0015] In further features, the building panel has an outer panel surface; and the insert includes an outer insert surface configured as a build surface. The outer insert surface extends beyond the outer panel surface before expanding.

[0016] In further features, the container is defined by an inner sidewall of the build plate. The inner sidewall is tapered outwardly from an outer plate surface of the build plate, such that the container is smallest at the outer plate surface. The insert has a tapered side surface opposite the inner sidewall. In response to expansion, the angled side surface of the insert slides along the inner sidewall of the container to draw the insert from an outer position into the container to an inner position.

[0017] In further features, the build plate assembly is configured to be mounted on a lifting platform of the additive manufacturing machine.

[0018] The present disclosure further includes, in various features, a method of forming a product on a build plate with an additive manufacturing machine. The method comprises the steps of: heating an insert of a build plate with a heating element contained in a base supporting the insert, the build plate defining a receptacle in which the insert is housed, and the insert having a build surface configured to support the product built thereon by the additive manufacturing machine; depositing material on the insert; heating the material to fuse the material and form the product; and cooling the insert with a cooling element of the base.

[0019] In further features, the insert is configured to expand within the container when heated by heat transferred from the heating element to the insert, and the container is configured to accommodate the expansion.

[0020] In further features, the insert is configured to contract after expansion in response to cooling by the base's cooling element.

[0021] The present disclosure further includes, in various features, an additive manufacturing machine having a lifting platform and a build plate assembly configured to be mounted to the lifting platform. The build plate assembly includes: a build plate defining a container extending through the build plate; an insert seated in the container and movable within the container, the insert having a build surface configured to support a product built thereon by the additive manufacturing machine; and a base upon which the insert sits, the base including a heating element configured to heat the insert and a cooling element configured to cool the insert.The insert is configured to expand to an expanded configuration within the container in response to heating by the base's heating element, and the container is configured to accommodate or facilitate the expansion. The insert is configured to contract from the expanded configuration in response to cooling by the base's cooling element.

[0022] Further areas of applicability of the present disclosure will become apparent from the detailed description, claims, and drawings. The detailed description and specific examples are provided for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] This disclosure will become more fully apparent from the detailed description and the accompanying drawings, in which: Fig. 1 is a perspective view of a build plate assembly according to the present disclosure mounted on an additive manufacturing machine; Fig. 2 is a cross-sectional view of the build plate assembly mounted on a lifting platform of the additive manufacturing machine; Fig. 3 is a cross-sectional view of the build plate assembly with a product being formed on an insert thereof by additive manufacturing; Fig. 4 is a cross-sectional view of the building panel assembly with the product formed therein; Fig. 5 is a plan view of another building panel assembly according to the present disclosure, the building panel assembly including a plurality of inserts each having a build surface; and Fig. 6 is a cross-sectional view taken along line 6-6 of Fig. 5.

[0024] Reference numbers may be reused in the drawings to identify similar and / or identical elements. DETAILED DESCRIPTION

[0025] Fig. 1 shows a build plate assembly 10 according to the present disclosure. The build plate assembly 10 is configured to be mounted on an additive manufacturing machine 110, which is configured to manufacture any suitable product on the build plate assembly 10. The additive manufacturing machine 110 may be any suitable machine configured to manufacture the product by applying a plurality of layers of material to the build plate assembly 10, for example, by three-dimensional printing. The additive manufacturing machine 110 may, for example, be a metal additive manufacturing machine. The additive manufacturing machine 110 may be configured to manufacture any suitable vehicle-related products, such as engine components, dashboard components, user interface components (e.g., buttons, knobs, switches, etc.).), body components, door handles, interior door components, exhaust tips, etc. The additive manufacturing machine 110 may be configured to produce products for use in any suitable vehicle, e.g., any suitable passenger vehicle, commuter vehicle, aircraft, watercraft, commercial vehicle, construction vehicle, etc. The additive manufacturing machine 110 may be configured to produce products for any application other than vehicles.

[0026] With continued reference to Fig. 1 and additional reference to Fig. 2, the build plate assembly 10 includes a build plate 20 having a plurality of openings 22 configured to receive any suitable fasteners 24. The fasteners 24 are configured to attach the build plate assembly 10 to a lifting platform 112 of the additive manufacturing machine 110. The build plate 20 includes an outer plate surface 30 and an inner plate surface 32 facing away from the outer plate surface 30. An insulator 70 is attached to the inner plate surface 32 by means of the fasteners 24. Between the insulator 70 and the lifting platform 112 is a support plate 34, which is securely fastened in position by the fasteners 24.

[0027] The building panel 20 defines or forms a container 40 between the outer panel surface 30 and the inner panel surface 32. More specifically, an inner sidewall 42 of the building panel 20 extends from the outer panel surface 30 to the inner panel surface 32. The inner sidewall 42 defines the container 40. The inner sidewall 42 is angled outwardly from the outer panel surface 30 to the inner panel surface 32. The inner sidewall 42 can, for example, have an angle of about 5° to about 40°.

[0028] An insert 50 is located inside the container 40. The insert 50 is movable within the container 40 to accommodate the expansion and contraction of the insert 50 in response to heat generated during manufacturing. The insert 50 includes an outer insert surface 52 and an inner insert surface 54 facing away from the outer insert surface 52. The outer insert surface 52 is configured as a build surface upon which the additive manufacturing machine 110 builds the product. An angled side surface 56 of the insert 50 extends from the outer insert surface 52 to the inner insert surface 54. The angled side surface 56 tapers outwardly from the outer insert surface 52 to the inner insert surface 54. The angled side surface 56 is chamfered to match an angle of the inner side wall 42.The angled side surface 56 abuts the inner sidewall 42 to prevent the powder from which the product is made from becoming trapped between the insert 50 and the build plate 20. The angled side surface 56 of the insert 50 slides along the inner sidewall 42 as the insert 50 expands and contracts during the additive manufacturing process, as explained herein.

[0029] The insert 50 may be formed in any suitable manner. For example, the insert 50 may be machined from the build plate 20 by wire EDM, waterjet cutting, or another suitable process. The insert 50 may also be machined from any suitable starting material instead of being formed from the build plate 20. The container 40 of the build plate 20 may be machined into the build plate 20 to provide the inner side wall 42 with an angle that matches that of the sloped side surface 56 of the insert 50.

[0030] Before the insert 50 is inserted into the container 40 of the build plate 20, it may be machined to include various features. For example, the insert 50 may be machined to include inlet and outlet openings for cooling or heating channels, ejector pin holes, heat measurements, a vent line, etc. Plugs may be inserted into the pre-machined openings in the insert 50 to prevent powder from falling into the machined openings during manufacturing. After the finished part has been removed from the build plate 20, the plugs may be removed, and the internal features of the part may be cleaned of powder as needed. The plugs may be reusable and designed to fit into the openings and be held in place with, for example, a threaded plug or an interference fit pin.

[0031] The build plate 20 has a modulus and hardness equal to or greater than the modulus and hardness of the insert 50. To increase the wear resistance of the build plate 20, the inner sidewall 42 may be carburized or nitrided to locally increase the hardness on the inner sidewall 42 where the insert 50 contacts the inner sidewall 42. Alternatively, the inner sidewall 42 may be coated with a material that is harder than the insert 50. The inner sidewall 42 and the angled side surface 56 may be machined smooth, e.g., by polishing to less than about Ra = 4 µm, and an elevated temperature stable lubricant, such as graphite, may be applied to the inner sidewall 42 and / or the angled side surface 56 to allow the insert 50 to move freely and smoothly.

[0032] The build plate 20 is placed on top of the insulator 70. The insulator 70 is any suitable insulator used to insulate the build plate 20. The insulator 70 includes a side wall 72 and an insulator flange 74. The side wall 72 defines an insulator receptacle 76. Located within the insulator receptacle 76 is a base 80 upon which the insert 50 sits. The base 80 is in direct contact with the insert 50. The base 80 includes a base flange 82 configured to bear against the insulator flange 74. Gaps are provided between the base 80 and the insulator 70 to allow the base 80 to expand when heated.

[0033] The base 80 is made of any heat-conducting material, e.g., copper or an aluminum alloy. The base 80 contains any suitable heating and cooling elements. In some applications, the base 80 may contain only the heating elements or only the cooling elements. In the example shown, heating elements in the form of heating rods 84 extend through the base 80 and transfer heat to the base 80 when current flows through the heating rods 84. Heating coils may also be used instead of or in addition to the heating rods 84. The base 80 shown also contains cooling elements in the form of cooling lines 86 configured in any suitable manner to cool the base 80. For example, a suitable coolant may be passed through the cooling lines 86 to cool the base 80. Suitable coolants include cooled inert gas (e.g., Ar gas), cooled liquid that does not react with deposited powder (e.g.,Mineral oil / glycol), Peltier coolers, cooling pins, etc. The cooling lines 86 may be provided with holes. The base 80 may be manufactured in a suitable manner, e.g., by a suitable additive manufacturing process, forming channels for the heating rods 84 and the cooling lines 86. The insulator 70 and / or the lifting platform 112 may include suitable passages for accommodating cooling lines and electrical connections for the heating rods 84.

[0034] Fig. 3 shows a first portion 170 of a product being formed by the additive manufacturing machine 110 on the insert 50. Before forming the product, the insert 50 may be heated by the heating elements of the base 80. For example, current may be passed through the heating rods 84 to heat the base 80. The heat from the base 80 is transferred to the insert 50, which is in contact with the base 80. As the insert 50 is heated, it expands outward and downward, e.g., in the direction of the arrows in Fig. 3. Before heating, the outer insert surface 52 is flush with or protrudes beyond the outer insert surface 52. When heated, the insert 50 moves into the container 40. Preheating the insert 50 minimizes the temperature difference between the insert 50 and the powder 150 molten thereon. Preheating also slows the cooling rate in the molten pool area at the outer insert surface 52, which reduces the risk of thermal deformation or cracking. Heating the insert 50 can reduce residual stresses and deformation caused by the rapid temperature increases and decreases due to the speed of the laser melting process. Heating can also improve the homogeneity of the heat distribution, leading to a more predictable result and greater manufacturing success.

[0035] The temperature of the base 80 can be continuous or variable during the construction process. Thus, the heating profile can change during the construction process. For example, the heating temperature can be increased or decreased, or the heating can be turned off completely. For a tall structure, the heating rods 84 can be activated during the first few centimeters of construction to minimize deformation of the insert 50. The heating rods 84 can be deactivated as the structure grows taller.

[0036] To form the first portion 170, the powder 150 is first applied to the outer plate surface 30 of the build plate 20 and to the outer insert surface 52 of the insert 50. The build plate 20 may be made of any suitable material, e.g., a suitable alloy. The insert 50 may also be made of any suitable material, e.g., a suitable alloy, identical to or different from the alloy of the build plate 20. The powder 150 is any suitable powder alloy configured to be welded to the outer insert surface 52 by the laser 160. The alloy of the insert 50 may be identical to or different from the alloy of the powder 150.

[0037] A laser 160 fuses the powder 150 disposed on the outer insert surface 52 to produce the first portion 170 of the product. Numerous layers of powder 150 are applied and heated by the laser 160 to build the product layer by layer. As the powder 150 is heated by the laser 160, heat may be transferred to the insert 50, depending on the temperature to which the insert 50 was preheated by the base 80. As the insert 50 is heated by the base 80 and / or by the heat generated during laser melting, the insert 50 expands outward and downward, as indicated by the arrows in Fig. 3. As the insert 50 expands outwardly against the sloping inner side wall 42 of the container 40, the insert 50 expands from the outer position of Fig. 1 or Fig. 2 downwards towards the carrier plate 34 and into the container 40 into an inner position which is Fig. 3. As the insert 50 expands, the side surface 56 slides along the inner side wall 42 of the container 40, both of which are beveled to allow the insert 50 to expand into the container 40.

[0038] Fig. 4 shows a second portion 172 of the part being formed on the first portion 170. The second portion 172 is formed by fusing the powder 150 deposited on the first portion 170 with the laser 160. After the part is fully formed and the first portion 170 and the second portion 172 cool, the insert 50 also cools. Cooling of the insert 50 can be effected through the cooling lines 86, e.g., by passing coolant through the cooling lines 86. As the insert 50 cools, the insert 50 contracts back to its original shape and size. As shown in Fig. 4, biasing elements 60 (e.g., springs) move the base 80 and the insert 50 back to the outer position in which the outer insert surface 52 is flush with the outer plate surface 30 or projects outwardly beyond the outer plate surface 30, as in the example of Fig. 4. The cooling lines 86 assist heat dissipation during long build times for large parts and / or enable cooling after product completion. The cooling lines 86 can improve throughput by rapidly cooling the product by several hours after its manufacture and enable a degree of microstructure control during manufacturing. For example, excessive aging of certain alloys can be controlled by cooling the insert 50.

[0039] After the part is fully formed, the excess powder 150 is removed, and the build plate assembly 10 is removed from the additive manufacturing machine 110. The insert 50 with the part formed thereon is removed from the container 40 from the side of the inner plate surface 32. In some applications, the insert 50 is part of the product. Therefore, the insert 50 does not need to be separated from the first portion 170 of the product or from any other portion of the product. In other applications, the insert 50 may not be part of the product, so the insert 50 is suitably separated from the first portion 170.

[0040] Once the insert 50 has been removed from the build plate 20, the build plate 20 can be reused to form an additional product on another insert located within the container 40. Thermal stresses resulting from repeated, rapid heating and cooling of the build layers are contained or absorbed by the insert 50. As a result, the build plate 20 is not permanently deformed by plastic deformation. Preventing permanent deformation of the build plate 20 also extends the service life of other components of the build plate assembly 10 and the additive manufacturing machine 110. For example, the fasteners 24 can also be reused, and a powder coating arm for applying the powder 150 is protected from potential damage.

[0041] In Fig. 5, another build plate 20' according to the present disclosure is illustrated. The build plate 20' includes a plurality of receptacles, each configured to receive a different insert, e.g., a first insert 50A, a second insert 50B, and a third insert 50C. Fig. Figure 5 shows the build plate 20' configured to accommodate three inserts, but the build plate 20' may be configured to accommodate any number of inserts, e.g., two inserts or more than three inserts. The inserts may be of any suitable size and shape. In the example of Fig. 5, insert 50A is rectangular, insert 50B is square, and insert 50C is round. Each of inserts 50A, 50B, and 50C includes a build surface configured to support a product formed thereon by additive manufacturing machine 110.

[0042] One or more of the inserts 50A, 50B, 50C may have any suitable features for aligning with the features of the product built on the inserts 50A, 50B, 50C. For example, the insert 50C includes a plurality of openings 90, which may be configured as cooling lines. The openings 90 are aligned with the corresponding cooling lines of a product built on the insert 50C. Thus, the insert 50C is supplied as part of the product. To prevent the powder 150 from falling into the openings 90 while the product is being formed, plugs may be inserted into the openings 90. The openings 90 may be formed in the insert 50C in any suitable manner, for example, by machining prior to attaching the build plate 20' to the lifting platform 112. According Fig.6, the insert 50C may include a tab 92 configured to be received within a recess 94 of the build plate 20. The cooperation of the tab 92 and the recess 94 aligns the insert 50C and the openings 90 in the rotational direction during the build process.

[0043] The foregoing description is merely illustrative in nature and is not intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure may be embodied in a variety of forms. Therefore, while this disclosure contains specific examples, the true scope of the disclosure should not be so limited, since other modifications will become apparent upon a study of the drawings, the specification, and the following claims. It is to be understood that one or more steps within a method may be performed in a different order (or simultaneously) without altering the principles of the present disclosure.Although each of the embodiments is described above with specific features, any one or more of these features described with respect to any embodiment of the disclosure may be implemented in one of the other embodiments and / or combined with features of another embodiment, even if this combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and permutations of one or more embodiments with each other remain within the scope of this disclosure.

[0044] Spatial and functional relationships between elements (e.g., between modules, circuit elements, semiconductor layers, etc.) are described using various terms, e.g., "connected," "engaging," "coupled," "adjacent," "beside," "on," "over," "below," and "disposed." When a relationship between a first and a second element is not explicitly described as "direct" in the above disclosure, that relationship may be a direct relationship, with no other intervening elements present between the first and second elements, or it may be an indirect relationship, with one or more intervening elements (either spatial or functional) present between the first and second elements.As used herein, the phrase “at least one of A, B, and C” should be construed as logical (A OR B OR C) using a non-exclusive logical OR, and not as “at least one of A, at least one of B, and at least one of C.”

[0045] In the figures, the direction of an arrow, as indicated by the arrowhead, generally indicates the flow of information (e.g., data or instructions) of interest for the representation. For example, if element A and element B exchange a lot of information, but the information transmitted from element A to element B is relevant for the representation, the arrow may point from element A to element B. This unidirectional arrow does not imply that no further information is transmitted from element B to element A. Also, for information sent from element A to element B, element B may send requests for, or acknowledgments of, the information to element A.

Claims

[1] A build plate assembly configured for use with an additive manufacturing machine, the build plate assembly comprising: a build plate defining a container extending through the build plate; an insert seated in the container and movable within the container, the insert having a build surface configured to support a product built thereon by the additive manufacturing machine; and a base on which the insert sits, the base including a heating element configured to heat the insert; wherein the insert is configured to expand within the container when heated by the heating element, and the container is configured to accommodate the expansion. [2] The building panel assembly of claim 1, wherein the base includes a thermally conductive material. [3] The building panel assembly of claim 1, wherein the heating element comprises heating rods and / or heating coils configured to conduct current. [4] The build plate assembly of claim 1, wherein the base further includes a cooling element configured to cool the base and the insert. [5] The building panel assembly of claim 4, wherein the cooling element comprises cooling conduits configured to conduct a cooled coolant through the base. [6] Building board assembly according to claim 4, wherein the cooling element comprises at least cooling pins and / or Peltier coolers. [7] The building panel assembly of claim 1, wherein the base directly contacts the insert. [8] The building panel assembly of claim 1, further comprising an insulator defining an insulator receptacle, the base being seated in the insulator receptacle. [9] The building panel assembly of claim 8, wherein the insulator and the base define a gap therebetween. [10] The building panel assembly of claim 9, further comprising a support plate on a side of the insulator opposite the building panel, the support plate defining a portion of the insulator receptacle.

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