Piezoresistor forming die and forming method

Abstract

The invention relates to a pressure-sensitive resistor forming die and a forming method, the pressure-sensitive resistor forming die comprises a die body and a release agent coating device, the die body comprises a lower die and an outer die, the outer die is provided with a vertically through cavity, and when the lower die and the outer die relatively move to a powder feeding position, the release agent coating device coats the release agent coating device; a lower punch of the lower die is matched with the cavity to define a feeding cavity with an opening in the upper end, when the lower die and the outer die relatively move to a blank ejection position, the lower punch of the lower die ejects a pressed blank out of the upper surface of the outer die, and the release agent coating device comprises a release agent releasing mechanism and a release agent feeding mechanism; the release agent feeding mechanism is communicated with the release agent releasing mechanism through a pipeline, and the release agent releasing mechanism is arranged on a lower punch of the lower mold so as to coat the inner wall of a cavity of the outer mold with a release agent in the relative movement process of the lower mold and the outer mold. According to the forming die, the inner wall of the outer die cavity can be coated with the release agent, so that the friction force between the blank and the die is reduced, the double-fold eyelid spallation phenomenon is avoided, and the blank quality is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of varistor production, and in particular to a varistor forming die and a forming method. Background Art

[0002] Compared with resistors with a small aspect ratio, varistors with a large aspect ratio have obvious advantages in the production, manufacturing and application of lightning arresters. For example, the number of aluminum spraying and grinding required for resistors with a large aspect ratio is reduced exponentially, which can not only reduce costs but also improve production efficiency. At the same time, compared with resistors with a small aspect ratio, resistors with a large aspect ratio have a lower pressure ratio. However, resistors with a large aspect ratio have certain difficulties in the manufacturing process. When producing ZnO resistors, the resistor powder is first pressed into a blank in a varistor forming mold, and then the blank is fired into a resistor. During the pressing process, due to the large friction between the thick blank and the mold, the blank is subjected to uneven tension. The above reasons are likely to cause the blank to break, resulting in the "double eyelid cracking phenomenon". Summary of the invention

[0003] The first object of the present invention is to provide a varistor forming mold so that it can reduce the "double eyelid cracking phenomenon" on the surface of the embryo, improve the quality of the embryo, and further improve the quality of the resistor product.

[0004] The second object of the present invention is to provide a varistor forming method based on the above-mentioned varistor forming mold.

[0005] To achieve the above object, the present invention provides the following technical solutions: A varistor forming die, comprising: A mold body, wherein the mold body comprises a lower mold and an outer mold, wherein the outer mold is provided with a cavity penetrating from top to bottom, and when the lower mold and the outer mold relatively move to a powder feeding position, the lower punch of the lower mold cooperates with the cavity to enclose a feeding cavity with an upper opening, and when the lower mold and the outer mold relatively move to a body ejection position, the lower punch of the lower mold ejects the pressed body from the upper surface of the outer mold; A release agent coating device, the release agent coating device includes a release agent releasing mechanism and a release agent feeding mechanism, the release agent feeding mechanism is connected to the release agent releasing mechanism through a pipeline, and the release agent releasing mechanism is arranged on the lower punch of the lower mold to coat the release agent on the inner wall of the cavity of the outer mold during the relative movement of the lower mold and the outer mold.

[0006] In one embodiment of the present application, the release agent release mechanism includes a plurality of release holes, each of which is evenly distributed along the circumference of the lower punch of the lower die, the first end of the release hole forms an outlet on the outer circumferential surface of the lower punch of the lower die, the second end of the release hole extends into the inner cavity of the lower punch of the lower die, and the second end of the release hole is connected to the release agent feeding mechanism through a pipeline.

[0007] In one embodiment of the present application, the release agent release mechanism includes a storage cavity and a plurality of release holes, the storage cavity is arranged in the lower punch of the lower die, and the release holes are evenly distributed along the circumference of the lower punch of the lower die, the first end of the release hole forms an outlet on the outer peripheral surface of the lower punch of the lower die, the second end of the release hole is connected to the storage cavity, and the lower end of the storage cavity is connected to the release agent feeding mechanism through a pipeline.

[0008] In one embodiment of the present application, the release agent release mechanism also includes a wear-resistant porous sleeve, which is arranged outside the lower punch of the lower die, and the lower end of the wear-resistant porous sleeve is connected to the release agent feeding mechanism through a plurality of pipelines evenly spaced along the circumferential direction.

[0009] In one embodiment of the present application, the wear-resistant porous sleeve is wool felt or polytetrafluoroethylene porous membrane.

[0010] In one embodiment of the present application, the release agent release mechanism also includes a release ring, which has a plurality of release ports evenly distributed along the circumferential direction, and the outer circumferential surface of the lower punch of the lower die is provided with a groove, and the release ring is at least partially embedded in the groove, and the first end of the release hole is provided on the groove wall of the groove, and the release hole is connected to the release port.

[0011] In one embodiment of the present application, the release agent release mechanism also includes a nozzle, and an avoidance groove is provided on the outer peripheral surface of the lower punch of the lower mold. The nozzle is connected to the release hole in the avoidance groove to avoid the outer mold.

[0012] In one embodiment of the present application, the release agent feeding mechanism includes a peristaltic pump or a syringe pump.

[0013] In one embodiment of the present application, it also includes a controller and a position detection module, the controller is communicated with the position detection module and the release agent feeding mechanism respectively, the position detection module is used to detect the relative position of the outer mold and the lower mold, and the controller is used to control the release agent feeding mechanism to operate when the outer mold moves to a preset position relative to the lower mold.

[0014] A varistor forming method based on the varistor forming mold as described in any one of the above, comprising the steps of: The lower mold and the outer mold of the varistor molding mold are relatively moved to the powder feeding position, and the upper mold of the varistor molding mold is moved upward away from the lower mold and the outer mold to the mold opening position to form a feeding space; Load the resistor powder into the feeding cavity formed by the lower punch of the lower die and the cavity of the outer die; The upper die falls, and the upper punch of the upper die enters the feed cavity. The upper punch of the upper die cooperates with the lower punch of the lower die to press the resistor powder into an embryonic body. The upper die rises to the mold opening position, the lower die and the outer die of the varistor forming die move relatively to the embryo ejection position, and the lower punch of the lower die ejects the embryo from the upper surface of the outer die; The outer mold is reset to the powder feeding position relative to the lower mold, preparing for the next feeding, and the cycle is repeated. When the outer mold moves from the powder feeding position to the embryo ejection position or from the embryo ejection position to the powder feeding position relative to the lower mold, the release agent coating device starts to coat the release agent to the inner wall of the cavity of the outer mold.

[0015] It can be seen from the above technical scheme that the present invention discloses a varistor forming mold, which includes a mold body and a release agent coating device, wherein the mold body includes a lower mold and an outer mold, and the outer mold is provided with a cavity penetrating from top to bottom. When the lower mold and the outer mold move relative to each other to the powder feeding position, the lower punch of the lower mold cooperates with the cavity to form a feeding cavity with an upper opening. When the lower mold and the outer mold move relative to each other to the embryo ejection position, the lower punch of the lower mold ejects the pressed embryo from the upper surface of the outer mold. The release agent coating device includes a release agent releasing mechanism and a release agent feeding mechanism. The release agent feeding mechanism is connected to the release agent releasing mechanism through a pipeline. The release agent releasing mechanism is arranged on the lower punch of the lower mold, so as to apply the release agent to the inner wall of the cavity of the outer mold during the relative movement of the lower mold and the outer mold.

[0016] During application, when the lower mold and the outer mold move from the embryo ejection position to the powder feeding position or from the powder feeding position to the embryo ejection position, the release agent coating device is started, and the release agent is sprayed or brushed onto the inner wall of the cavity according to the preset feeding amount and feeding time. Then, when the lower mold and the outer mold are in the powder feeding position, the resistor powder is put into the feeding cavity, the upper mold and the lower mold are closed, and the upper punch and the lower punch cooperate to press the resistor powder into an embryo. In this process, the release agent can reduce the friction between the embryo and the mold, and reduce the uneven tension on the embryo, thereby avoiding the "double eyelid cracking phenomenon", improving the embryo quality, and then improving the quality of the resistor chip product. Moreover, since only a small amount of release agent is coated on the surface of the cavity, the amount of release agent adhering to the embryo is limited and only located on the surface of the embryo, and the product quality will not be affected by excessive release agent residue. In the subsequent firing and debinding process, organic gas emissions can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A schematic structural diagram of a varistor forming mold provided by an embodiment of the present invention; Figure 2 A schematic structural diagram of a lower punch of a lower die of a varistor forming die provided by an embodiment of the present invention; Figure 3 A front view of a lower punch of a lower die of a varistor forming die provided by an embodiment of the present invention; Figure 4 for Figure 3 Sectional view at A in the middle; Figure 5 A front view of a lower punch of a lower die of a varistor forming die provided in another embodiment of the present invention;.

[0019] In the figure: 1 is a varistor forming mold; 110 is a lower mold; 111 is a base; 112 is a lower punch; 1121 is a limiting groove; 120 is an outer mold; 121 is a cavity; 130 is an upper mold; 131 is a rising plate; 132 is an upper punch; 2 is a release agent coating device; 210 is a release agent feeding mechanism; 220 is a conversion head; 230 is a release agent releasing mechanism; 231 is a release hole; 232 is a storage cavity. DETAILED DESCRIPTION

[0020] One of the cores of the present invention is to provide a varistor forming mold, the structural design of the varistor forming mold enables it to reduce the "double eyelid cracking phenomenon" on the surface of the embryo, improve the quality of the embryo, and further improve the quality of the resistor product.

[0021] Another core of the present invention is to provide a varistor forming method based on the above-mentioned varistor forming mold.

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] See also Figure 1 , Figure 1A schematic structural diagram of a varistor forming mold provided in an embodiment of the present invention.

[0024] An embodiment of the present invention discloses a varistor forming mold 1 , which includes a mold body and a release agent coating device 2 .

[0025] The mold body includes an upper mold 130, a lower mold 110 and an outer mold 120. The upper mold 130 includes a rising plate 131 and a plurality of upper punches 132 arranged on the lower surface of the rising plate 131. The rising plate 131 can drive the upper punches 132 to move relative to the lower mold 110 and the outer mold 120 below to achieve mold closing and mold opening. The lower mold 110 includes a base 111 and a plurality of lower punches 112 arranged on the base 111. The number of the lower punches 112 is equal to the number of the upper punches 132, and the working surface of the upper punch 132 is equal to the working surface shape and area of ​​the lower punch 112, that is, the lower end surface of the upper punch 132 is equal to the upper end surface shape and area of ​​the lower punch 112. The outer mold 120 is provided with a cavity 121 that runs through from top to bottom. The lower mold 110 and the outer mold When the lower mold 110 and the outer mold 120 move relatively to the powder feeding position, the lower punch 112 of the lower mold 110 cooperates with the cavity 121 to form a feeding cavity with an upper opening, that is, the upper end surface of the lower punch 112 blocks the bottom end of the cavity 121. When the lower mold 110 and the outer mold 120 move relatively to the embryo ejection position, the lower punch 112 of the lower mold 110 ejects the pressed embryo from the upper surface of the outer mold 120. The release agent coating device 2 includes a release agent releasing mechanism 230 and a release agent feeding mechanism 210. The release agent feeding mechanism 210 is connected to the release agent releasing mechanism 230 through a pipeline. The release agent releasing mechanism 230 is arranged on the lower punch 112 of the lower mold 110 to apply the release agent to the inner wall of the cavity 121 of the outer mold 120 during the relative movement of the lower mold 110 and the outer mold 120.

[0026] Compared with the prior art, the varistor forming mold 1 provided in the embodiment of the present invention is used. When the lower mold 110 and the outer mold 120 move from the embryo ejection position to the powder feeding position or from the powder feeding position to the embryo ejection position, the release agent coating device 2 is started, and the release agent is sprayed or brushed on the inner wall of the cavity 121 according to the preset feeding amount and feeding time. Then, when the lower mold 110 and the outer mold 120 are in the powder feeding position, the resistor powder is put into the feeding cavity, the upper mold 130 and the lower mold 110 are molded together, and the upper punch 132 and the lower punch are pressed together. The head 112 cooperates to press the resistor powder into a embryo. During this process, the release agent can reduce the friction between the embryo and the mold, and reduce the uneven tension on the embryo, thereby avoiding the "double eyelid cracking phenomenon", improving the embryo quality, and then improving the quality of the resistor product. Moreover, since only a small amount of release agent is coated on the surface of the cavity 121, the amount of release agent adhering to the embryo is limited and only located on the surface of the embryo. The product quality will not be affected by excessive release agent residue. In the subsequent firing and debinding process, organic gas emissions can be reduced.

[0027] like Figure 2 and Figure 3 As shown, in the embodiment of the present invention, the release agent release mechanism 230 includes a plurality of release holes 231, each of which is evenly distributed along the circumference of the lower punch 112 of the lower die 110, and the first end of the release hole 231 forms an outlet on the outer circumferential surface of the lower punch 112 of the lower die 110, and the second end of the release hole 231 extends into the inner cavity of the lower punch 112 of the lower die 110, and the second end of the release hole 231 is connected to the release agent feeding mechanism 210 through a pipeline. 2, the release holes 231 can be straight holes or L-shaped holes, 3 to 8 release holes 231 can be evenly distributed along the circumferential direction, and the distance between the release holes 231 and the upper end surface of the lower punch 112 is 3 mm to 5 mm, all the release holes 231 can be set at the same horizontal position, or multiple groups of release holes 231 can be set, each group of release holes 231 includes 3 to 8 release holes 231 evenly distributed along the circumferential direction, and each group of release holes 231 is arranged along the axial direction of the lower punch 112.

[0028] In another embodiment, if Figure 4 As shown, the release agent release mechanism 230 includes a storage cavity 232 and a plurality of release holes 231. The storage cavity 232 is arranged in the lower punch 112 of the lower mold 110. The release holes 231 are evenly distributed along the circumference of the lower punch 112 of the lower mold 110. The first end of the release hole 231 forms an outlet on the outer peripheral surface of the lower punch 112 of the lower mold 110. The second end of the release hole 231 is connected to the storage cavity 232. The lower end of the storage cavity 232 is connected to the release agent feeding mechanism 210 through a pipeline.

[0029] In the above embodiment, since the release agent is applied without relying on other structures except the release hole 231 , the lower punch 112 can adopt a structure with equal diameters from top to bottom.

[0030] In another embodiment of the present application, the release agent release mechanism 230 also includes a wear-resistant porous sleeve, which is arranged outside the lower punch 112 of the lower die 110. The lower end of the wear-resistant porous sleeve is connected to the release agent feeding mechanism 210 through a plurality of pipes evenly spaced along the circumferential direction. To facilitate the installation of the wear-resistant porous sleeve, the lower punch 112 should adopt a variable diameter structure, such as Figure 5 As shown, a limiting groove 1121 is provided on the outer peripheral surface of the lower punch 112 , and a wear-resistant porous sleeve is arranged in the limiting groove 1121 to prevent the wear-resistant porous sleeve from axial movement during the relative movement of the lower die 110 and the outer die 120 .

[0031] In the above embodiment, the wear-resistant porous sleeve may not be connected to the pipeline, but a release hole 231 is set on the groove wall of the limiting groove, and the wear-resistant porous sleeve directly covers the release hole 231. The release hole 231 is used to release the release agent directly onto the wear-resistant porous sleeve. The release agent passes through the wear-resistant porous sleeve and is brushed onto the inner wall of the cavity 121 by the wear-resistant porous sleeve, or the wear-resistant porous sleeve can pass through the release hole 231 to extend into the interior of the lower punch 112 and be connected to the release agent feeding mechanism 210.

[0032] To further optimize the above technical solution, in one embodiment of the present application, the wear-resistant porous sleeve is wool felt or polytetrafluoroethylene porous membrane, the thickness of the wear-resistant porous sleeve is 1 mm to 7 mm, the width is 0.5 mm to 5 mm, and the outer diameter is the same as the maximum outer diameter of the lower punch 112.

[0033] Preferably, the cross-section of the wear-resistant porous sleeve may be C-shaped to facilitate removal from the lower punch 112 .

[0034] Of course, in addition to the above-mentioned embodiments, the release agent release mechanism 230 can also adopt other structures. For example, in another embodiment, the release agent release mechanism 230 also includes a release ring, and the release ring has multiple release ports evenly distributed along the circumferential direction. The outer peripheral surface of the lower punch 112 of the lower mold 110 is provided with a groove, and the release ring is at least partially embedded in the groove. The first end of the release hole 231 is provided on the groove wall of the groove, and the release hole 231 is connected to the release port. One or more release rings can be arranged at axial intervals along the lower punch 112, and the release ring is made of soft elastic material, such as silicone rubber.

[0035] In another embodiment, the release agent release mechanism 230 also includes a nozzle, which applies the release agent by spraying. An avoidance groove is set on the outer peripheral surface of the lower punch 112 of the lower mold 110, and the nozzle is connected to the release hole 231 in the avoidance groove to avoid the outer mold 120.

[0036] The release agent feeding mechanism 210 can adopt a peristaltic pump or a syringe pump, but is certainly not limited to these two types. Specifically, in one embodiment of the present application, the release agent feeding mechanism 210 is a micro-injection pump, and the output end of the micro-injection pump is connected to the release agent release mechanism 230 on each lower punch 112 through a conversion head 220.

[0037] In order to accurately control the release agent feeding time and reduce the amount of release agent used, in an embodiment of the present application, the varistor forming mold 1 also includes a controller and a position detection module. The controller is communicated with the position detection module and the release agent feeding mechanism 210 respectively. The position detection module is used to detect the relative position of the outer mold 120 and the lower mold 110. The controller is used to control the release agent feeding mechanism 210 to work when the outer mold 120 moves to a preset position relative to the lower mold 110, so as to achieve accurate control of the feeding timing.

[0038] The embodiment of the present invention further provides a varistor forming method based on the varistor forming mold 1 described in the embodiment, comprising the steps of: The lower mold 110 and the outer mold 120 of the varistor molding mold 1 move relative to each other to the powder feeding position, and the upper mold 130 of the varistor molding mold 1 moves upward away from the lower mold 110 and the outer mold 120 to the mold opening position to form a feeding space. If it is used for the first time, the lower mold 110 and the outer mold 120 move relative to each other to the powder feeding position. They should first move to the embryo ejection position, and then move to the powder feeding position. In the process of moving from the embryo ejection position to the powder feeding position, the release agent coating device 2 starts to coat the release agent to the inner wall of the cavity 121.

[0039] The resistor powder is loaded into the feeding cavity surrounded by the lower punch 112 of the lower die 110 and the cavity 121 of the outer die 120 .

[0040] The upper die 130 falls, and the upper punch 132 of the upper die 130 enters the feed cavity. The upper punch 132 of the upper die 130 cooperates with the lower punch 112 of the lower die 110 to press the resistor powder into an embryonic body.

[0041] The upper mold 130 rises to the mold opening position, the lower mold 110 and the outer mold 120 of the varistor molding mold 1 move relatively to the embryo ejection position, and the lower punch 112 of the lower mold 110 ejects the embryo from the upper surface of the outer mold 120 .

[0042] The outer mold 120 is reset to the powder feeding position relative to the lower mold 110, preparing for the next feeding, and repeating the cycle. When the outer mold 120 moves from the powder feeding position to the embryo ejection position or from the embryo ejection position to the powder feeding position relative to the lower mold 110, the release agent coating device 2 starts to coat the release agent to the inner wall of the cavity 121 of the outer mold 120.

[0043] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0044] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the core idea of ​​the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, the present invention can also be improved and modified, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A varistor forming die, characterized in that: include: A mold body, wherein the mold body comprises a lower mold and an outer mold, wherein the outer mold is provided with a cavity penetrating from top to bottom, and when the lower mold and the outer mold relatively move to a powder feeding position, the lower punch of the lower mold cooperates with the cavity to enclose a feeding cavity with an upper opening, and when the lower mold and the outer mold relatively move to a body ejection position, the lower punch of the lower mold ejects the pressed body from the upper surface of the outer mold; A release agent coating device, the release agent coating device includes a release agent releasing mechanism and a release agent feeding mechanism, the release agent feeding mechanism is connected to the release agent releasing mechanism through a pipeline, and the release agent releasing mechanism is arranged on the lower punch of the lower mold to coat the release agent on the inner wall of the cavity of the outer mold during the relative movement of the lower mold and the outer mold.

2. The varistor forming die according to claim 1, characterized in that: The demolding agent releasing mechanism comprises a plurality of releasing holes, each of which is evenly distributed along the circumference of the lower punch of the lower die, a first end of each of the releasing holes forms an outlet on the outer peripheral surface of the lower punch of the lower die, a second end of each of the releasing holes extends into the inner cavity of the lower punch of the lower die, and the second end of each of the releasing holes is connected to the demolding agent feeding mechanism through a pipeline.

3. The varistor forming die according to claim 1, characterized in that: The release agent release mechanism includes a storage cavity and a plurality of release holes, wherein the storage cavity is arranged in the lower punch of the lower die, and each of the release holes is evenly distributed along the circumference of the lower punch of the lower die, and the first end of the release hole forms an outlet on the outer peripheral surface of the lower punch of the lower die, and the second end of the release hole is connected to the storage cavity, and the lower end of the storage cavity is connected to the release agent feeding mechanism through a pipeline.

4. The varistor forming die according to claim 1, characterized in that: The release agent release mechanism also includes a wear-resistant porous sleeve, which is arranged outside the lower punch of the lower die, and the lower end of the wear-resistant porous sleeve is connected to the release agent feeding mechanism through a plurality of pipelines evenly spaced along the circumferential direction.

5. The varistor forming die according to claim 4, characterized in that: The wear-resistant porous sleeve is wool felt or polytetrafluoroethylene porous membrane.

6. The varistor forming die according to claim 2 or 3, characterized in that: The release agent release mechanism also includes a release ring, which has a plurality of release ports evenly distributed along the circumferential direction. The outer circumferential surface of the lower punch of the lower die is provided with a groove, and the release ring is at least partially embedded in the groove. The first end of the release hole is provided on the groove wall of the groove, and the release hole is connected to the release port.

7. The varistor forming die according to claim 2 or 3, characterized in that: The release agent release mechanism also includes a spray head. An avoidance groove is provided on the outer peripheral surface of the lower punch of the lower die. The spray head is connected with the release hole in the avoidance groove to avoid the outer die.

8. The varistor forming die according to any one of claims 1 to 5, characterized in that: The release agent feeding mechanism includes a peristaltic pump or a syringe pump.

9. The varistor forming die according to any one of claims 1 to 5, characterized in that: It also includes a controller and a position detection module, wherein the controller is communicated with the position detection module and the release agent feeding mechanism respectively, the position detection module is used to detect the relative position of the outer mold and the lower mold, and the controller is used to control the release agent feeding mechanism to operate when the outer mold moves to a preset position relative to the lower mold.

10. A varistor forming method based on the varistor forming mold according to any one of claims 1 to 9, characterized in that: Includes steps: The lower mold and the outer mold of the varistor molding mold are relatively moved to the powder feeding position, and the upper mold of the varistor molding mold is moved upward away from the lower mold and the outer mold to the mold opening position to form a feeding space; Load the resistor powder into the feeding cavity formed by the lower punch of the lower die and the cavity of the outer die; The upper die falls, and the upper punch of the upper die enters the feed cavity. The upper punch of the upper die cooperates with the lower punch of the lower die to press the resistor powder into an embryonic body. The upper die rises to the mold opening position, the lower die and the outer die of the varistor forming die move relatively to the embryo ejection position, and the lower punch of the lower die ejects the embryo from the upper surface of the outer die; The outer mold is reset to the powder feeding position relative to the lower mold, preparing for the next feeding, and the cycle is repeated. When the outer mold moves from the powder feeding position to the embryo ejection position or from the embryo ejection position to the powder feeding position relative to the lower mold, the release agent coating device starts to coat the release agent to the inner wall of the cavity of the outer mold.

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