Sintering bearing jig

Abstract

The embodiment of the utility model discloses a sintering bearing jig which comprises a bottom plate and two opposite side walls, and five sequentially adjacent positioning faces are arranged on the bottom plate; the first positioning surface and the third positioning surface have the same depth, the second positioning surface is deeper than the first positioning surface, the fourth positioning surface is deeper than the second positioning surface, and the fifth positioning surface is deeper than the fourth positioning surface. According to the sintering bearing jig, a plurality of profiling positioning surfaces are designed on the bottom surface of the jig to carry out fool-proof and avoidance on a product structure, uniform and effective auxiliary support is formed for a product, and serious deformation caused by hindered interference in the sintering shrinkage process of the product is prevented. According to the sintering bearing jig, the sintering shrinkage complexity of a strip-shaped product with a thin wall and a porous structure can be reduced, the problem of sintering deformation is fundamentally solved, and the production cost is reduced.

Description

Technical Field

[0001] This application relates to the field of powder injection molding, and particularly to a sintering carrier jig. Background Art

[0002] Metal Powder Injection Molding (MIM for short) is an advanced manufacturing technology that mixes metal powder with an organic binder and then injects and molds it, and then makes precision metal parts through processes such as debinding and sintering. MIM is a product of combining powder metallurgy technology and plastic injection molding technology. Compared with traditional processes, MIM has many advantages such as low manufacturing cost, high production efficiency, high product precision, high complexity, and mass production, and is widely used in fields such as electronic communication, smart wearables, automobiles, medical equipment, military, and aerospace.

[0003] The sintering process is the most difficult to control in the metal powder injection molding process. The feedstock contains 40% by volume of a high molecular binder (POM) that will be decomposed during the debinding and sintering processes, thus resulting in a large linear shrinkage. The products are often uncontrollable during the sintering process due to frictional force and gravity, especially for complex structural parts, and deformation is more likely to occur during the sintering process. Therefore, for the production of hinge products by the MIM process, it is very difficult to control the sintering process to reduce deformation. Utility Model Content

[0004] To solve the existing technical problems, the embodiments of this application provide a sintering carrier jig. The technical solutions are as follows:

[0005] In a first aspect, a sintering carrier jig is provided. The carrier jig includes a bottom plate and two opposite side walls. Five adjacent positioning surfaces are arranged on the bottom plate in sequence; the first positioning surface and the third positioning surface have the same depth, the depth of the second positioning surface is greater than that of the first positioning surface, the depth of the fourth positioning surface is greater than that of the second positioning surface, and the depth of the fifth positioning surface is greater than that of the fourth positioning surface.

[0006] Optionally, limiting grooves are correspondingly arranged on the two side walls, and limiting bars can be installed in the limiting grooves.

[0007] Optionally, the first positioning surface has a depth of 3.00 ± 0.05 cm, the second positioning surface has a depth of 3.82 ± 0.03 cm, the fourth positioning surface has a depth of 3.95 ± 0.03 cm, and the fifth positioning surface has a depth of 5.01 ± 0.03 cm.

[0008] Optionally, the first positioning surface has a width of 15.85 cm, the second positioning surface has a width of 7.10 cm, the third positioning surface has a width of 8.36 cm, the fourth positioning surface has a width of 10.43 cm, and the fifth positioning surface has a width of 7.62 cm.

[0009] Optionally, the width of the limit groove is 3.10 ± 0.03 cm.

[0010] Optionally, a plurality of the limit grooves are arranged along the side wall, and the distance between two adjacent limit grooves is 3.02 ± 0.03 cm.

[0011] Optionally, the sintering carrier fixture is made of ceramic.

[0012] Optionally, the heat resistance temperature of the ceramic is > 1100 °C.

[0013] Optionally, the ceramic is alumina ceramic, and the alumina ceramic comprises Al2O3 ≥ 99%, SiO2 ≤ 0.20%, Na2O ≤ 0.15%, Fe2O3 ≤ 0.10%, and MgO ≤ 0.10%.

[0014] The beneficial effects brought by the technical solution provided by the embodiment of the present application are as follows: The sintering carrier fixture of the present application includes a bottom plate and two opposite side walls, and five sequentially adjacent positioning surfaces are arranged on the bottom plate; the first positioning surface and the third positioning surface have the same depth, the depth of the second positioning surface is greater than that of the first positioning surface, the depth of the fourth positioning surface is greater than that of the second positioning surface, and the depth of the fifth positioning surface is greater than that of the fourth positioning surface. The sintering carrier fixture of the present application prevents product structure from being misused and provides avoidance by designing a plurality of profiling positioning surfaces on the bottom surface of the fixture, forms uniform and effective auxiliary support for the product, and prevents the product from being blocked and interfered during the sintering shrinkage process, resulting in serious deformation. The sintering carrier fixture of the present application can reduce the sintering shrinkage complexity of products with strip-shaped, thin-wall, and porous structures, fundamentally solve the problem of sintering deformation, and reduce production costs. Description of the Drawings

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0016] Figure 1 is a side view of the sintering carrier fixture provided in Embodiment 1 of the present application;

[0017] Figure 2 is a top view of the sintering carrier fixture provided in Embodiment 1 of the present application;

[0018] Figure 3 is a key dimension distribution diagram of the sintered product prepared by the sintering carrier fixture provided in Embodiment 1 of the present application;

[0019] Figure 4 is a key dimension distribution diagram of the sintered product prepared by a conventional sintering carrier fixture. Detailed implementation mode

[0020] To make the objectives, technical solutions and advantages of this application clearer, the following will further describe the implementation modes of this application in detail with reference to the accompanying drawings.

[0021] It should be clear that the described embodiments are only a part of the embodiments of this application, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this application without creative efforts belong to the scope of protection of this application.

[0022] When the following description refers to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The implementation modes described in the following exemplary embodiments do not represent all implementation modes consistent with this application. On the contrary, they are only examples of devices and methods consistent with some aspects of this application as detailed in the appended claims.

[0023] In the description of this application, it should be understood that the terms "first", "second", "third", etc. are only used to distinguish similar objects and do not have to be used to describe a specific order or sequence, nor can they be understood as indicating or implying relative importance. In the description of this application, unless otherwise specified, "a plurality" means two or more.

[0024] Embodiment 1 Sintering carrier jig

[0025] As Figure 1 and Figure 2 described sintering carrier jig, includes a bottom plate 1 and two opposite side walls 2, and five adjacent positioning surfaces are arranged on the bottom plate 1.

[0026] The first positioning surface 11 and the third positioning surface 13 have the same depth, the second positioning surface 12 has a greater depth than the first positioning surface 11, the fourth positioning surface 14 has a greater depth than the second positioning surface 12, and the fifth positioning surface 15 has a greater depth than the fourth positioning surface 14.

[0027] In practice, considering the size of the sintering furnace, the size of the sintering jig, and the size of the workpiece to be sintered, two bottom plates 1 can be arranged side by side on the same sintering jig. The two bottom plates 1 share the middle side wall 2.

[0028] In this application, the first positioning surface 11 and the third positioning surface 13 have the same depth, both are 3.00 ± 0.05 cm, the second positioning surface 12 is 3.82 ± 0.03 cm deep, the fourth positioning surface 14 is 3.95 ± 0.03 cm deep, and the fifth positioning surface 15 is 5.01 ± 0.03 cm deep.

[0029] The first positioning surface 11 has a width of 15.85 cm, the second positioning surface 12 has a width of 7.10 cm, the third positioning surface 13 has a width of 8.36 cm, the fourth positioning surface 14 has a width of 10.43 cm, and the fifth positioning surface 15 has a width of 7.62 cm. The side wall 2 has a width of 7.09 cm.

[0030] In practice, since the size of the sintering carrier jig is much larger than that of the workpiece to be sintered, the workpieces to be sintered are usually placed in columns on the sintering carrier jig. Therefore, in order to prevent the workpieces to be sintered from affecting each other during the sintering process and to prevent the position movement or collapse of the workpieces to be sintered during the degreasing and sintering turnover process, a plurality of limiting grooves 21 can be correspondingly provided on the side wall 2, and limiting bars can be installed in the limiting grooves 21. Generally, the limiting groove 21 is designed to have a width of 3.10 ± 0.03 cm, and the interval between two adjacent limiting grooves 21 is 3.02 ± 0.03 cm.

[0031] The length of the bottom plate 1 can be designed according to the actual depth of the sintering furnace. In practical applications, during the process of taking, placing, and transferring the sintering carrier jig into and out of the sintering furnace, the workpieces to be sintered at the front and rear ends of the sintering carrier jig are prone to falling due to being close to the edge. Therefore, the positions of the first (and the last) limiting grooves 21 can be adjusted so that the first workpiece to be sintered has a larger space. Therefore, the first limiting groove 21 and the last limiting groove 21 at the front and rear ends of the side wall 2 are respectively 5.61 cm away from the edge of the sintering carrier jig.

[0032] The sintering carrier jig and the limiting bars are made of high-density alumina ceramics (Al2O3 ≥ 99%, SiO2 ≤ 0.20%, Na2O ≤ 0.15%, Fe2O3 ≤ 0.10%, MgO ≤ 0.10%) as materials, with a heat-resistant temperature > 1100 °C, or other high-temperature-resistant ceramics can also be used as materials.

[0033] The sintering carrier jig obtained in this application is subjected to physical and chemical tests, and the results are shown in Table 1.

[0034] Table 1 Physical and Chemical Indexes of the Sintering Carrier Jig

[0035]

[0036]

[0037] Example 2 Sintering Treatment

[0038] (1) A green body with a density of 5.35 - 5.40 g / cm 3 is prepared by low-pressure injection (100 MPa - 140 MPa). The appearance quality of the green body is good and there is no stress.

[0039] (2) After placing the green blanks into the sintering carrier fixture of the above embodiment in sequence, place them in a debinding furnace for catalytic debinding treatment. The pre-rinse time is 60 min; the debinding time is 180 - 300 min, the debinding temperature is 100 - 120 °C, the acid injection rate is 2 - 4.5 g / min; the post-rinse time is 60 min; during the debinding process, nitrogen is injected into the debinding furnace throughout the process for protection, the nitrogen temperature is 120 °C, and the nitrogen flow rate is 70 - 90 L / min.

[0040] (3) Transfer the sintering carrier fixture together with the green blanks after catalytic debinding to a sintering furnace, perform negative pressure debinding at room temperature - 800 °C, the heating rate is 1.5 - 2 °C / min, the holding time is 60 min, and nitrogen is injected into the sintering furnace for protection during the negative pressure debinding process, the nitrogen flow rate is 40 L / min; perform vacuum sintering at 800 - 1050 °C, the heating rate is 4 °C / min, the holding time is 60 min; perform partial pressure sintering at 1050 - 1385 °C, the heating rate is 3 °C / min, the holding time is 180 - 300 min, argon is injected into the sintering furnace for protection during the partial pressure sintering process, the argon flow rate is 30 L / min, the sintering pressure is 20 - 50 KPa, and after the holding is completed, cool to room temperature and take out of the furnace.

[0041] Using the sintering carrier fixture of the present application and a conventional sintering carrier fixture, 4 groups of products are fired respectively according to the method of Example 2. Detect the key dimensions of the products, and the results are as Figure 3 and Figure 4 shown. The sizes of the sintered products obtained by the sintering carrier fixture of the present application are all between 0.50 - 0.60 mm, the median is about 0.55, and the yield rate reaches 99%, indicating that the product size data obtained by using the sintering carrier fixture of the present application is concentrated, the dispersion is small, and the yield rate of good products is high. The sizes of the sintered products obtained by the conventional sintering carrier fixture vary greatly, the median is between 0.54 - 0.58 mm, and the qualified rate is only 78%, indicating that the products obtained by using the conventional sintering fixture have large deformation and large dispersion, and the qualified rate is low. Through the above comparison, it can be seen that the sintering carrier fixture of the present application can effectively improve the deformation situation of the products during the sintering process.

[0042] During the high-temperature sintering process of MIM green blanks, the linear shrinkage of the product in length, width, and height is about 10% - 15%. Due to the self-gravity of the product and the frictional force generated at the contact surface between the shrinkage process and the carrier fixture, it is difficult to avoid the product deformation problem. In order to minimize the degree of product distortion as much as possible, it is necessary to analyze the product structure and develop and design the most reasonable sintering carrier fixture for auxiliary support.

[0043] The sintering carrier fixture of the present application prevents misoperation and avoids interference with the product structure by designing multiple profiling positioning surfaces on the bottom surface of the fixture, forming uniform and effective auxiliary support for the product, preventing the product from being blocked and interfered during the sintering shrinkage process and causing serious deformation. At the same time, a limiting strip is introduced to prevent the product from moving or collapsing during the turnover process of degreasing and sintering. The sintering carrier fixture is made of 99% high-density alumina ceramic material. The smooth surface effect of the fixture can reduce the friction between the product and the fixture during the sintering shrinkage process, thereby improving the product deformation problem. The above combination of fixture material selection and fixture structure design reduces the sintering shrinkage complexity of products with strip-shaped, thin-walled, and porous structures, fundamentally solves the sintering deformation problem, and reduces production costs.

[0044] The above are only the preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the scope of the claims of the present application.

Claims

1. A sintering support tool, characterized in that: The supporting jig includes a bottom plate and two opposite side walls, and five adjacent positioning surfaces are arranged on the bottom plate; the first positioning surface has the same depth as the third positioning surface, the second positioning surface has a depth greater than the first positioning surface, the fourth positioning surface has a depth greater than the second positioning surface, and the fifth positioning surface has a depth greater than the fourth positioning surface.

2. The sintering support tool according to claim 1, characterized in that: The two side walls are correspondingly provided with limiting grooves, and limiting strips can be installed in the limiting grooves.

3. The sintering support tool according to claim 1, characterized in that: The first positioning surface is 3.00±0.05 cm deep, the second positioning surface is 3.82±0.03 cm deep, the fourth positioning surface is 3.95±0.03 cm deep, and the fifth positioning surface is 5.01±0.03 cm deep.

4. The sintering support tool according to claim 1, characterized in that: The first positioning surface is 15.85 cm wide, the second positioning surface is 7.10 cm wide, the third positioning surface is 8.36 cm wide, the fourth positioning surface is 10.43 cm wide, and the fifth positioning surface is 7.62 cm wide.

5. The sintering support tool according to claim 2, characterized in that: A plurality of the limiting grooves are arranged along the side wall, and the interval between two adjacent limiting grooves is 3.02±0.03 cm.

6. The sintering support tool according to claim 2, characterized in that: The limiting groove has a width of 3.10±0.03 cm.

7. The sintering support tool according to claim 1, characterized in that: The sintering tool is made of ceramic.

8. The sintering support tool according to claim 7, characterized in that: The ceramic is alumina ceramic.

9. The sintering support tool according to claim 8, characterized in that: The ceramic has a heat-resistant temperature greater than 1100°C.

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