Sintering jig

Abstract

The sintering jig comprises a supporting plate and rolling bodies, a plurality of grooves or concave holes matched with the rolling bodies are formed in the surface of the supporting plate, and the rolling bodies are movably installed in the grooves or the concave holes; a workpiece to be sintered is placed on the multiple rolling bodies. Rolling bodies are arranged on the supporting plate and can move relative to the supporting plate, and a supporting plane can be formed by the multiple rolling bodies. When a to-be-sintered workpiece is placed on the supporting plane formed by the rolling bodies to be sintered and shrunk, original sliding friction can be changed into rolling friction, so that friction force is greatly reduced, resistance generated when the workpiece is sintered and shrunk is avoided to a great extent, consistency of vertical shrinkage of the sintered workpiece is improved, and sintering quality is improved.

Description

Technical Field

[0001] The utility model relates to a tool used in a heat treatment process, in particular to a sintering tool for binder jetting 3D printing of metal products. Background Art

[0002] Binder Jetting Additive Manufacturing (BJAM) involves laying a layer of metal powder on a work surface. A nozzle then sprays a binder onto the powder layer as needed, gradually building up the layers. Low-temperature curing is then performed to create a green metal body with sufficient strength. Degreasing and sintering then yield metal components with adequate mechanical properties. Compared to traditional machining techniques and other 3D printing technologies, binder jetting offers advantages such as high efficiency, low cost, and the ability to form complex structures. Furthermore, the mechanical properties of products printed using binder jetting are isotropic, resulting in improved service life. Therefore, it has a wide range of applications.

[0003] Products formed using BJAM technology require high-temperature sintering to achieve the density required for use. Because BJAM technology uses a binder to bond metal powder, the resulting green bodies have high porosity and uneven density fluctuations, leading to volume shrinkage during subsequent sintering. Currently used sintering jigs are mostly plate-shaped. During sintering, the green body rests on the jig. If the green body is heavy, its own weight increases friction between the bottom green body and the jig, hindering the green body's bottom shrinkage. This rate of contraction is inconsistent with the free contraction of the upper part, causing the green body to deform or warp, impacting product quality and performance. Summary of the Invention

[0004] Based on this, the anti-deformation sintering fixture proposed in the present invention can effectively solve the problems of product deformation and low yield caused by sintering fixtures in existing solutions, and effectively improve the quality of sintered products.

[0005] A sintering jig comprises: a support plate and rolling bodies, wherein the surface of the support plate is provided with a plurality of grooves or recessed holes matching the rolling bodies, and each of the rolling bodies is movably mounted in the grooves or recessed holes; and a workpiece to be sintered is placed on the plurality of rolling bodies.

[0006] The sintering fixture utilizes a split design, with rolling elements mounted on a support plate. The rolling elements are movable relative to the support plate, forming a support surface. When the workpiece to be sintered is placed on the support surface formed by the rolling elements and shrinks during sintering, the original sliding friction is converted into rolling friction. This significantly reduces friction, largely eliminating resistance during sintering shrinkage, improving the consistency of the vertical shrinkage of the sintered part, and enhancing sintering quality.

[0007] In one embodiment, the rolling element is made of high-temperature resistant ceramic material.

[0008] On the one hand, high-temperature resistant ceramic materials can withstand high temperatures during the sintering process to avoid deformation. On the other hand, the ceramic material has a smooth surface and low friction, which can reduce the shrinkage resistance of the green body during the sintering process.

[0009] In one embodiment, the high temperature resistant ceramic material is aluminum oxide, zirconium oxide or iridium oxide.

[0010] In one embodiment, the support plate and the rolling element can be made of different types of high-temperature resistant ceramic materials.

[0011] The supporting plate and the rolling element are made of different high-temperature resistant ceramic materials and can be applied to the sintering of different green bodies (powder materials, powder particle sizes).

[0012] In one embodiment, the surface of the rolling element is provided with a coating.

[0013] Providing a smooth coating on the surface of the rolling element can further reduce the relative friction between the rolling element and the sintered product.

[0014] In one embodiment, the support plate includes a first mounting portion and a second mounting portion, and the first mounting portion and the second mounting portion cooperate to form a plurality of cavities for accommodating the rolling bodies; the first mounting portion is provided with grooves or recessed holes that match the rolling bodies.

[0015] The split support plate design allows for customization to suit different heat treatment requirements for different sintered parts. For example, the first mounting portion and rolling elements can be designed and replaced based on the size of the part being sintered.

[0016] In one embodiment, the first mounting portion and the second mounting portion are detachably connected.

[0017] In one embodiment, the first mounting portion and the second mounting portion can be mounted by snapping, screwing, or hinged connection.

[0018] The detachable connection allows for quick replacement and installation, improving efficiency.

[0019] In one embodiment, the rolling body is a ball, a round rod, a roller or a bearing.

[0020] The sphere and rod have curved surfaces, minimizing contact area; they can also rotate within the support plate, further reducing friction. The bearing itself can rotate, converting sliding friction into rolling friction, further reducing friction.

[0021] In one embodiment, the fitting clearance between the rolling element and the support plate is no more than 2 mm.

[0022] Setting a gap between the support plate and the rolling element can, on the one hand, satisfy the rotation of the rolling element and convert sliding friction into rolling friction; on the other hand, controlling the gap can reduce the overhang area between the sintered part and the supporting plane, which is more conducive to sintering shrinkage.

[0023] A sintering jig significantly reduces the friction between the bottom sintering surface of a part and the sintering jig compared to existing sintering jigs, replacing existing sliding friction with rolling friction, reducing the risk of sintering deformation of parts and improving the yield and sintering quality of sintered parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of an embodiment of a sintering jig;

[0025] Figure 2 This is a cross-sectional schematic diagram of an embodiment of a sintering jig;

[0026] Figure 3 This is a partial schematic diagram of an embodiment of a sintering jig;

[0027] Figure 4 This is a partial schematic diagram of an embodiment of a sintering jig;

[0028] Figure 5 This is a partial schematic diagram of an embodiment of a sintering jig;

[0029] Figure 6 This is a schematic diagram of another embodiment of a sintering jig;

[0030] In the attached figure:

[0031] 10-support plate, 101-first mounting portion, 102-second mounting portion;

[0032] 20-rolling element, 201-ball, 202-round rod, 203-bearing

[0033] 30-concave hole;

[0034] 40-grooves. DETAILED DESCRIPTION

[0035] To facilitate understanding of the present invention, a more comprehensive description of the present invention will be provided below with reference to the accompanying drawings. The accompanying drawings illustrate preferred embodiments of the present invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the disclosure of the present invention.

[0036] In this document, "green body", "part to be sintered" and "sintered product" all refer to metal printed products that are formed by binder jet printing and not sintered at high temperature. It should be noted that when an element is referred to as being "disposed on" another element, it can be directly on the other element or there can be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there can be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right", "top", "bottom", "bottom end", "top end" and similar expressions used in this document are for illustrative purposes only and do not represent the only implementation method.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of this invention are intended solely for the purpose of describing specific embodiments and are not intended to limit this invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0038] In one embodiment, a sintering jig includes: a support plate and rolling bodies, wherein the surface of the support plate is provided with a plurality of grooves or recessed holes matching the rolling bodies, and each of the rolling bodies is movably mounted in the grooves or recessed holes; and the workpiece to be sintered is placed on the plurality of rolling bodies.

[0039] The sintering fixture utilizes a split design, with rolling elements mounted on a support plate. The rolling elements are movable relative to the support plate, forming a support surface. When the workpiece to be sintered is placed on the support surface formed by the rolling elements and shrinks during sintering, the original sliding friction is converted into rolling friction. This significantly reduces friction, largely eliminating resistance during sintering shrinkage, improving the consistency of the vertical shrinkage of the sintered part, and enhancing sintering quality.

[0040] The sintering jig is described below in conjunction with specific embodiments to further understand the concept of the sintering jig. Figure 1 A sintering jig includes: a support plate 10 and a rolling body 20. Specifically, the support plate 10 is provided with a cavity for accommodating the rolling body, and the surface is provided with a plurality of recessed holes 30 that match the rolling body 20. The rolling body is movably embedded in the cavity of the support plate and matches the recessed holes. In this way, the support plate surface and the rolling body can form a supporting plane. The workpiece to be sintered is placed on the support plate, and its bottom is in direct contact with the support plate and the rolling body. When high-temperature sintering is carried out, when the bottom of the workpiece to be sintered undergoes micro-movement (displacement) relative to the support plate and the rolling body during shrinkage, the rolling body rotates, changing the original sliding friction into rolling friction, reducing the resistance during shrinkage, improving the consistency of the upper and lower shrinkage of the workpiece to be sintered, and improving the sintering quality.

[0041] It should be noted that the recessed holes on the support plate can be arranged linearly or circumferentially, or can be customized according to the bottom shape or size of the sintered part. It should be noted that the recessed holes can be square holes, circular holes or polygonal holes.

[0042] In one embodiment, the rolling body may be in the shape of a sphere, such as a ball; or a cylinder, such as a round rod or a round shaft; or a self-rotating structural bearing or roller.

[0043] It should be noted that, in one embodiment, in order to ensure that the rolling body is firmly installed and the rolling body does not fall off or displace when the sintering fixture is transported or moved, a shielding structure is designed on the support plate so that the rolling body only rotates within the support plate during operation and will not fall off the support plate.

[0044] In one embodiment, reference may be made to Figure 2-5 The support plate may be provided with a plurality of linearly arranged grooves 40 that cooperate with the rolling elements. The groove widths may match the rotational diameter of the rolling elements. Specifically, the grooves may be linear elongated grooves with square, polygonal, or circular cross-sections. Each elongated groove may be embedded with a plurality of balls, one or more circular shafts or rods, or multiple bearings.

[0045] The rolling element is embedded in the groove, with its highest point flush with the support plate. The part to be sintered is placed on the plane formed by the rolling element and the support plate surface. During high-temperature sintering, the bottom of the part shrinks due to the heat, allowing the rolling element to rotate to reduce friction between the bottom and the sintering fixture.

[0046] In one embodiment, to prevent deformation of the sintering jig during the sintering process, which could affect the sintering quality and precision of the sintered part, the rolling elements and support plates are made of high-temperature resistant ceramic materials. Furthermore, the finished product made of ceramic materials can be treated to a smooth surface, reducing friction and further facilitating the reduction of shrinkage resistance during the sintering process. Specifically, the high-temperature resistant ceramic material may be aluminum oxide, zirconium oxide, or iridium oxide.

[0047] In one embodiment, to facilitate molding or assembly, the support plate and rolling element can be made of different types of high-temperature resistant ceramic materials to increase compatibility. Furthermore, using different ceramic materials to make the support plate and rolling element can also be used for sintering products with different powder particle sizes and different powder materials.

[0048] In one embodiment, a lubricious coating may be applied to the surface of the rolling element to further reduce the relative friction between the rolling element and the sintered product.

[0049] In one embodiment, referring to the attached Figure 6The support plate 10 includes a first mounting portion 101 and a second mounting portion 102. The first and second mounting portions cooperate to form multiple cavities for accommodating the rolling elements. The first mounting portion is provided with slots or holes that match the rolling elements (just enough to allow the rolling elements to be visible). During assembly, the rolling elements are first placed on the second mounting portion, and then the first mounting portion is snapped onto the second mounting portion to secure them.

[0050] In one embodiment, the first mounting part and the second mounting part are designed with a detachable connection structure. For example, a snap-fit ​​structure or mounting holes are provided on the first mounting part and the second mounting part, and the mounting is performed by snap-fitting or screwing. Alternatively, a hinged structure may be provided on one side of the two mounting parts, and a snap-fit ​​or screw-fitting structure may be provided on the other side. Any method that can achieve detachability is acceptable, and this embodiment does not impose any specific restrictions. The two-part sintering jig in which the support plate is provided as a detachable mount can not only be reused, but also can be adapted to different working conditions. For example, when the sintering jig needs to be replaced or maintained after a batch of green bodies is sintered, it is only necessary to disassemble and replace the first mounting part and / or the rolling element, and the second mounting part does not need to be replaced. Or if green bodies of different volumes or shapes need to be sintered, it is only necessary to open the support plate and replace the first mounting part and the rolling element, and the second mounting part does not need to be replaced.

[0051] In one embodiment, to ensure the rolling elements can rotate within the support plate, sliding friction is converted to rolling friction. Furthermore, to minimize the overhang between the sintered component and the support surface, the clearance between the rolling elements and the support plate is 2 mm or less. Specifically, the clearance between the outer surface of the rolling elements and the inner surface of the cavity formed by the support plate is within 2 mm. It should also be noted that to minimize the impact of the sintering jig on the green body's shrinkage, smaller and more closely spaced rolling elements on the support plate are more conducive to green body shrinkage.

[0052] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0053] The above-described embodiments merely represent several implementations of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements fall within the scope of protection of the present invention. Therefore, the scope of protection of the present utility model patent shall be determined by the appended claims.

Claims

1. A sintering jig, characterized in that: The sintering jig includes: a support plate and rolling bodies. The surface of the support plate is provided with multiple grooves or recessed holes matching the rolling bodies. Each rolling body is movably installed in the grooves or recessed holes. The workpiece to be sintered is placed on multiple rolling bodies.

2. The sintering jig according to claim 1, characterized in that: The rolling element is made of high-temperature resistant ceramic material.

3. The sintering jig according to claim 2, characterized in that: The high temperature resistant ceramic material is aluminum oxide, zirconium oxide or iridium oxide.

4. The sintering jig according to claim 2 or 3, characterized in that: The supporting plate and the rolling element can be made of different types of high-temperature resistant ceramic materials.

5. The sintering jig according to claim 1, characterized in that: The surface of the rolling element is provided with a coating.

6. The sintering jig according to claim 1, characterized in that: The support plate includes a first mounting portion and a second mounting portion, and the first mounting portion and the second mounting portion cooperate to form a plurality of cavities for accommodating the rolling bodies; the first mounting portion is provided with grooves or recessed holes that match the rolling bodies.

7. The sintering jig according to claim 6, characterized in that: The first mounting portion and the second mounting portion are detachably connected.

8. The sintering jig according to claim 6, characterized in that: The first mounting portion and the second mounting portion can be mounted by snapping, screwing, or hinged connection.

9. The sintering jig according to claim 1, characterized in that: The rolling body is a ball, a round rod, a roller or a bearing.

10. The sintering jig according to claim 1, characterized in that: The fitting clearance between the rolling element and the supporting plate is no greater than 2 mm.

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