A demolding method for preparing thermoelectric materials

Abstract

This invention discloses a demolding method for preparing thermoelectric materials, aiming to overcome the shortcomings of the demolding process where thermoelectric materials are easily damaged. The invention includes the following steps: S1, transferring the sintered thermoelectric material and sintering mold together to a demolding base; installing several inner lining sheets inside the sintering mold to form a sintering cavity; placing the thermoelectric material inside the sintering cavity; S2, pressing down with a demolding head to force the inner lining sheets and thermoelectric material out of the sintering mold; S3, the inner lining sheets and thermoelectric material fall into the demolding cavity on the demolding base, and then separating the inner lining sheets and thermoelectric material to achieve complete demolding of the thermoelectric material. The demolding method of this patent application facilitates demolding of the prepared thermoelectric material, prevents the thermoelectric material from easily sintering with the mold, and reduces the risk of damage and cracking during demolding.

Description

Technical Field

[0001] This invention relates to the field of thermoelectric semiconductor materials, and more specifically, to a method for demolding the preparation of thermoelectric materials. Background Technology

[0002] Currently, thermoelectric materials are a class of materials that can directly convert heat energy and electrical energy into each other, occupying a very important position in new energy materials. A common preparation method for thermoelectric materials is powder metallurgy. The conventional demolding method for powder metallurgy thermoelectric materials involves directly applying pressure to the upper / lower pressure rods to eject the material from the mold. This method directly or indirectly applies pressure to the material, causing relative displacement between the material and the mold to complete demolding. When using the above demolding method with other metal molds, bismuth telluride-based materials tend to sinter together with the mold, resulting in strong bonding. If pressure is directly applied to the material for demolding, relative displacement between the material and the mold can occur. When the shear force exceeds the material's tolerance, the material may crack, leading to low crystal rod preparation efficiency and low subsequent crystal rod utilization. Summary of the Invention

[0003] To overcome the above shortcomings, the present invention provides a demolding method for preparing thermoelectric materials. The thermoelectric materials are easy to demold after preparation, the thermoelectric materials are not easily sintered with the mold, and the thermoelectric materials are not easily damaged or cracked during the demolding process.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a demolding method for preparing thermoelectric materials, comprising the following steps:

[0005] S1, the sintered thermoelectric material and sintering mold are transferred together to the demolding base. Several inner lining sheets are installed in the sintering mold. The inner lining sheets form a ring to form a sintering cavity. The thermoelectric material is placed in the sintering cavity.

[0006] S2, the demolding head presses downwards, so that the inner liner and thermoelectric material are pressed out of the sintering mold together;

[0007] S3, the inner liner and the thermoelectric material fall together into the demolding cavity on the demolding seat, and then the inner liner and the thermoelectric material are separated to achieve complete demolding of the thermoelectric material.

[0008] During the demolding process of thermoelectric material preparation, pressure is applied to the inner liner using a demolding head, ejecting the thermoelectric material and the inner liner together from the sintering mold. This prevents displacement of the inner liner and the thermoelectric material, reduces the shear force on the thermoelectric material, and achieves rapid demolding, ensuring the integrity of the thermoelectric material. The demolding method described in this patent application facilitates demolding of the thermoelectric material after preparation, prevents the thermoelectric material from easily sintering with the mold, and minimizes the risk of damage and cracking during demolding.

[0009] Preferably, before S2, a demolding positioning piece is installed on the upper end of the sintering mold, with the inner edge of the demolding positioning piece aligned with the inner edge of the sintering mold.

[0010] The demolding positioning plate protects the sintering mold and prevents the demolding head from pressing on the sintering mold and causing damage if it is not aligned.

[0011] Preferably, a release lubricant layer is provided on the inner wall of the inner liner.

[0012] The release lubrication layer prevents the thermoelectric material from reacting or sticking with the inner liner during sintering. After sintering, the inner liner and thermoelectric material can be easily separated after demolding.

[0013] Preferably, the inner diameter of the demolding cavity is larger than the inner diameter of the sintering mold.

[0014] This structural design ensures that the inner liner and thermoelectric material can be demolded together into the demolding cavity.

[0015] Preferably, the depth of the demolding cavity is greater than the height of the sintering mold. This ensures that the inner liner and thermoelectric material can be fully accommodated within the demolding cavity.

[0016] Preferably, the lower part of the demolding head is adapted to the sintering mold, the outer diameter of the lower part of the demolding head is smaller than the inner diameter of the sintering mold, and a flange is provided on the upper part of the demolding head, the outer diameter of the flange is larger than the inner diameter of the sintering mold.

[0017] The flange serves as a limit, preventing the demolding head from pressing in too far.

[0018] Preferably, the demolding base is provided with a positioning groove that is compatible with the sintering mold, and the lower part of the sintering mold is fitted into the positioning groove during S1.

[0019] The positioning groove allows the sintering mold to be accurately loaded onto the demolding base, ensuring precise and reliable positioning.

[0020] Preferably, an inner buffer bladder and an outer buffer bladder are installed in the demolding cavity, with the outer buffer bladder surrounding the inner buffer bladder and the upper end of the outer buffer bladder being lower than the upper end of the inner buffer bladder; the upper contour of the inner buffer bladder is within the contour range of the sintering cavity.

[0021] The inner buffer bladder effectively cushions the thermoelectric material, while the outer buffer bladder cushions the inner liner, preventing the thermoelectric material from falling directly into the end of the demolding cavity and causing damage during demolding. Furthermore, the height difference between the inner and outer buffer bladders facilitates the separation of the inner liner and the thermoelectric material after they fall.

[0022] Preferably, several lower ejector rods are installed on the demolding head and the inner liner in a one-to-one correspondence. A connecting rod is hinged to the demolding head and the lower ejector rods respectively. One end of the connecting rod is movably connected to the lower ejector rod, and the other end of the connecting rod is movably connected to the upper ejector rod. The upper ejector rod extends downward out of the demolding head, and the lower end of the lower ejector rod retracts into the demolding head. In S2, the demolding head first pushes the inner liner and the thermoelectric material downward into the demolding cavity. The thermoelectric material is supported on the inner buffer bladder. The demolding head continues to press downward so that the upper ejector rod abuts against the sintering mold. The lower ejector rod extends downward and abuts against the inner liner, pushing the inner liner downward relative to the thermoelectric material and placing it on the outer buffer bladder.

[0023] During demolding, the inner and outer buffer bladders act as buffers, while the upper ejector rod is pushed upwards, causing the lower ejector rod to push the inner liner downwards, facilitating the separation of the inner liner and the thermoelectric material after demolding.

[0024] Preferably, a positioning spring is installed between the demolding head and the upper ejector pin. The positioning spring enables the positioning of the upper and lower ejector pins.

[0025] Compared with the prior art, the beneficial effects of the present invention are: the demolding method of this patent application makes it easy to demold the thermoelectric material after preparation, the thermoelectric material is not easily sintered with the mold, and the thermoelectric material is not easily damaged or cracked during the demolding process. Attached Figure Description

[0026] Figure 1 It is a structural schematic diagram of the present invention;

[0027] Figure 2 This is a cross-sectional view of Embodiment 1 of the present invention;

[0028] Figure 3 This is a schematic diagram of the structure of the inner liner sheet of the present invention;

[0029] Figure 4 This is a cross-sectional view of Embodiment 2 of the present invention;

[0030] In the diagram: 1. Sintering mold, 2. Demolding base, 3. Inner liner, 4. Sintering cavity, 5. Demolding positioning plate, 6. Demolding pressure head, 7. Demolding cavity, 8. Flange, 9. Positioning groove, 10. Inner buffer bladder, 11. Outer buffer bladder, 12. Lower ejector rod, 13. Connecting rod, 14. Upper ejector rod, 15. Positioning spring, 16. Long groove, 17. Connecting pin, 18. Mounting groove, 19. Upper positioning sleeve, 20. Lower positioning sleeve. Detailed Implementation

[0031] The technical solution of the present invention will be further described in detail below through specific embodiments and in conjunction with the accompanying drawings:

[0032] Example 1: A demolding method for preparing thermoelectric materials (see appendix) Figure 1 To be continued Figure 3 ), including the following steps:

[0033] S1, the sintered thermoelectric material and sintering mold 1 are transferred together to the demolding base 2. Several inner lining sheets 3 are installed inside the sintering mold, forming a sintering cavity 4. The thermoelectric material is placed inside the sintering cavity. A demolding lubrication layer is provided on the inner wall of the inner lining sheet. The demolding lubrication layer is formed by applying a lubricant. Common lubricants include graphite paper, lubricating oil, boron nitride, etc., or graphite with good lubricity and high strength can be selected as the material for the inner lining sheet to prevent the inner lining sheet and the thermoelectric material from reacting or sticking during the sintering process. In this embodiment, boron nitride is selected as the lubricant and sprayed on both sides of the inner lining sheet. A demolding positioning piece 5 is installed at the upper end of the sintering mold, and the inner edge of the demolding positioning piece is aligned with the inner edge of the sintering mold.

[0034] S2, the demolding head 6 presses downwards, causing the inner liner and thermoelectric material to be pressed out of the sintering mold together; at this time, from top to bottom are the demolding head, sintering mold, and demolding base;

[0035] S3, the inner liner and the thermoelectric material fall together into the demolding cavity 7 on the demolding seat, and then the inner liner and the thermoelectric material are separated to achieve complete demolding of the thermoelectric material, resulting in a complete thermoelectric material block.

[0036] The inner diameter of the demolding cavity is larger than the inner diameter of the sintering mold; the depth of the demolding cavity is greater than the height of the sintering mold. The lower part of the demolding head is adapted to the sintering mold, and the outer diameter of the lower part of the demolding head is smaller than the inner diameter of the sintering mold. A flange 8 is provided at the upper part of the demolding head, and the outer diameter of the flange is larger than the inner diameter of the sintering mold. In this embodiment, the inner diameter of the demolding cavity is 4mm larger than the inner diameter of the sintering mold, the depth of the demolding cavity is 7.5mm higher than the height of the sintering mold, and the inner diameter of the demolding positioning piece is no larger than the inner diameter of the thermoelectric material sintering mold and 1mm larger than the outer diameter of the demolding head. The thickness of the demolding positioning piece is 1mm. The outer diameter of the lower part of the demolding head is 3mm smaller than the inner diameter of the sintering mold. The height of the lower part of the demolding head is 2mm higher than the height of the sintering mold; the outer diameter of the upper part of the demolding head is 176mm larger than the inner diameter of the material sintering mold; the height of the upper part of the demolding head is 5mm.

[0037] During the demolding process of thermoelectric material preparation, pressure is applied to the inner liner using a demolding head, ejecting the thermoelectric material and the inner liner together from the sintering mold. This prevents displacement of the inner liner and the thermoelectric material, reduces the shear force on the thermoelectric material, and achieves rapid demolding, ensuring the integrity of the thermoelectric material. The demolding method described in this patent application facilitates demolding of the thermoelectric material after preparation, prevents the thermoelectric material from easily sintering with the mold, and minimizes the risk of damage and cracking during demolding.

[0038] Example 2: A demolding method for preparing thermoelectric materials, the steps of which are similar to those in Example 1, the main difference being that in this example, the inner liner is made of high-strength graphite material, and the graphite itself acts as a lubricant. Other steps are the same as in Example 1. After demolding, the upper surface of the graphite inner liner shows significant wear, indicating that the graphite inner liner mold is effective, but the mold itself experiences considerable wear.

[0039] Example 3: A demolding method for preparing thermoelectric materials, the steps of which are similar to those of Example 1 or Example 2, the main difference being that in this example, a positioning groove 9 adapted to the sintering mold is provided on the demolding seat, and in S1, the lower part of the sintering mold is adapted to be installed in the positioning groove. An inner buffer bladder 10 and an outer buffer bladder 11 are installed in the demolding cavity, both of which are air bladders. The outer buffer bladder is fitted around the inner buffer bladder, and the upper end of the outer buffer bladder is lower than the upper end of the inner buffer bladder; the upper contour of the inner buffer bladder is within the contour range of the sintering cavity. Several lower ejector rods 12 are installed correspondingly to the demolding head and the inner liner. Connecting rods 13 are hinged to the demolding head and the lower ejector rods, with the connecting rods angled. One end of the connecting rod is movably connected to the lower ejector rod, and the other end is movably connected to the upper ejector rod 14. The upper ejector rod extends downwards out of the demolding head, and the lower end of the lower ejector rod retracts into the demolding head. The upper ejector rod corresponds to the demolding positioning plate, and the lower ejector rod corresponds to the inner liner. A positioning spring 15 is installed between the demolding head and the upper ejector rod. Long slots 16 are provided at both ends of the connecting rod, and connecting pins 17 are provided on both the upper and lower ejector rods, with the two connecting pins movably inserted into the two long slots. Mounting slots 18 are provided on the demolding head and the connecting rod, with the connecting rod hinged to the side wall of the mounting slot. An upper positioning sleeve 19 and a lower positioning sleeve 20 are provided on the side wall of the mounting slot. The positioning spring abuts between the upper positioning sleeve and the upper ejector rod, and one end of the connecting rod abuts against the lower positioning sleeve for positioning. In step S2, the demolding head first pushes the inner liner and thermoelectric material downwards into the demolding cavity. The thermoelectric material is supported on the inner buffer bladder. The demolding head continues to press downwards, causing the upper ejector rod to abut against the sintering mold, and the lower ejector rod to extend downwards and abut against the inner liner, pushing the inner liner downwards relative to the thermoelectric material and placing it on the outer buffer bladder. Other steps are the same as in Example 1 or Example 2.

[0040] During demolding, the inner and outer buffer bladders act as a buffer, and the height difference between the inner and outer buffer bladders facilitates the separation of the inner liner and thermoelectric material after they fall. At the same time, the upper ejector is pushed upward, causing the lower ejector to push the inner liner downward, which facilitates the separation of the inner liner and thermoelectric material after demolding.

[0041] Comparative Example 1: The only difference between Comparative Example 1 and Example 1 is that Example 1 uses a demolding device to complete demolding, while Comparative Example 1 applies lubricant to both the inner liner of the mold and the inner surface of the outer mold sleeve, and uses a traditional demolding method to directly apply pressure to the mold head on the thermoelectric material to complete demolding.

[0042] Sintering is carried out under specific process parameters. After sintering, the thermoelectric material is demolded. The demolding machine directly applies pressure to the original pressure head of the sintering mold on the thermoelectric material to complete the demolding, resulting in an incomplete thermoelectric material block.

[0043] Comparative Example 2: The difference between Comparative Example 2 and Example 2 is that Example 2 uses a demolding device to complete demolding, while Comparative Example 2 uses a traditional demolding method, directly applying pressure to the mold head on the thermoelectric material to complete demolding.

[0044] Sintering is performed under specific process parameters. After sintering, the thermoelectric material is demolded. The demolding machine applies pressure directly to the thermoelectric material from the original pressure head of the sintering mold to complete the demolding, resulting in a relatively complete thermoelectric material block, but with surface defects. It is worth noting that the graphite inner liner mold suffered irreversible damage after demolding due to the strength limitations of graphite. In other words, under the same conditions, the prepared material is incomplete, and graphite cannot withstand this demolding condition.

[0045] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Other variations and modifications may be made without departing from the technical solutions described in the claims.

Claims

1. A method for demolding thermoelectric materials, characterized in that, Includes the following steps: S1, the sintered thermoelectric material and sintering mold are transferred together to the demolding base. Several inner lining sheets are installed in the sintering mold. The inner lining sheets form a ring to form a sintering cavity. The thermoelectric material is placed in the sintering cavity. S2, the demolding head presses downwards, so that the inner liner and thermoelectric material are pressed out of the sintering mold together; S3, the inner liner and the thermoelectric material fall together into the demolding cavity on the demolding seat, and then the inner liner and the thermoelectric material are separated to achieve complete demolding of the thermoelectric material; An inner buffer bladder and an outer buffer bladder are installed inside the demolding cavity, with the upper end of the outer buffer bladder lower than the upper end of the inner buffer bladder. Several lower ejector rods are installed in a corresponding manner on the demolding head and the inner liner. The demolding head and the lower ejector rods are connected by a hinged connecting rod. One end of the connecting rod is movably connected to the lower ejector rod, and the other end is movably connected to the upper ejector rod. The upper ejector rod extends downward out of the demolding head, and the lower end of the lower ejector rod retracts into the demolding head. In S2, the demolding head pushes the inner liner and thermoelectric material downward together into the demolding cavity. The thermoelectric material is supported by the inner buffer bladder. The demolding head continues to press downward so that the upper ejector rod abuts against the sintering mold, and the lower ejector rod extends downward and abuts against the inner liner, pushing the inner liner downward relative to the thermoelectric material and placing it on the outer buffer bladder.

2. The demolding method for preparing thermoelectric materials according to claim 1, characterized in that, Before S2, a demolding positioning piece is installed on the upper part of the sintering mold, with the inner edge of the demolding positioning piece aligned with the inner edge of the sintering mold.

3. The demolding method for preparing thermoelectric materials according to claim 1, characterized in that, A release lubricant layer is provided on the inner wall of the inner liner.

4. The demolding method for preparing thermoelectric materials according to claim 1, characterized in that, The inner diameter of the demolding cavity is larger than the inner diameter of the sintering mold.

5. The demolding method for preparing thermoelectric materials according to claim 1, characterized in that, The depth of the demolding cavity is greater than the height of the sintering mold.

6. The demolding method for preparing thermoelectric materials according to claim 1, characterized in that, The lower part of the demolding head is adapted to the sintering mold. The outer diameter of the lower part of the demolding head is smaller than the inner diameter of the sintering mold. A flange is provided at the upper part of the demolding head, and the outer diameter of the flange is larger than the inner diameter of the sintering mold.

7. A demolding method for preparing thermoelectric materials according to any one of claims 1 to 6, characterized in that, The demolding base is provided with a positioning groove that is compatible with the sintering mold. During S1, the lower part of the sintering mold is fitted into the positioning groove.

8. The demolding method for preparing thermoelectric materials according to claim 1, characterized in that, The outer buffer bladder is fitted around the inner buffer bladder; the upper contour of the inner buffer bladder is located within the contour range of the sintering cavity.

9. The demolding method for preparing thermoelectric materials according to claim 1, characterized in that, A positioning spring is installed between the demolding head and the upper ejector pin.

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