A mould wall lubrication arrangement

Abstract

The application relates to a die wall lubricating structure and relates to the technical field of powder metallurgy. The die wall lubricating structure comprises an upper die punch, a middle die and a lower die punch, the middle die is provided with a forming cavity penetrating through two ends of the middle die, the lower die punch comprises a lower punch auxiliary connecting piece and a lower punch head fixedly installed on the lower punch auxiliary connecting piece, the lower punch auxiliary connecting piece is provided with a liquid inlet channel in communication with the outside, the lower punch head is provided with a flow guide channel, one end of the flow guide channel is in communication with the liquid inlet channel, and the other end of the flow guide channel is in communication with the forming cavity. The application has the effects of precisely controlling the lubricant amount and improving product quality.

Description

Technical Field

[0001] This application relates to the technical field of powder metallurgy, and in particular to a mold wall lubrication structure. Background Technology

[0002] Powder forming technology has been widely used in the manufacturing of powder products in metal, ceramic, and bakelite industries due to its ability to produce high-precision, smooth, and complex-shaped parts in a single press, as well as its wide applicability, high production efficiency, and high material utilization. In particular, with the rapid development of next-generation communication technologies, the demand for complex-shaped, thin-walled ceramic components is increasing, placing higher demands on powder forming technology. In existing technologies, a certain proportion of lubricant is usually added to the powder to ensure a smooth pressing process. The main function of the lubricant is to reduce friction between powder particles and between the powder and the mold wall, thereby improving the flowability and mixing uniformity of the powder, reducing pressing force consumption, and protecting the mold.

[0003] Lubricant needs to be removed before the subsequent sintering process. If sufficient lubricant is added to ensure smooth pressing, it will leave pores and voids during removal due to volatilization and decomposition. This will lead to a decrease in product density, affecting properties such as tensile strength and hardness. Furthermore, uneven lubricant distribution may cause inconsistent shrinkage during sintering, resulting in deformation or cracking. Conversely, if the amount of lubricant is reduced to pursue high density, it will lead to uneven compact density, making it difficult to fill complex cavities, and similarly, failing to obtain high-quality products. Utility Model Content

[0004] To address the problem that existing technologies struggle to form high-density and uniformly sized pressed products without reducing the amount of lubricant in the powder, this application provides a mold wall lubrication structure.

[0005] The mold wall lubrication structure provided in this application adopts the following technical solution: A mold wall lubrication structure includes an upper mold punch, a middle mold, and a lower mold punch. The middle mold has a forming cavity extending through both ends of the middle mold. The lower mold punch includes a lower punch auxiliary connector and a lower punch head fixedly installed on the lower punch auxiliary connector. The lower punch auxiliary connector has a liquid inlet channel communicating with the outside. The lower punch head has a flow guide channel. One end of the flow guide channel is connected to the liquid inlet channel, and the other end of the flow guide channel is connected to the forming cavity.

[0006] By adopting the above technical solution, one end of the guide channel is connected to and connected to the liquid inlet channel, while the other end opens on the side of the lower punch that contacts the forming cavity. Lubricant flows through the liquid inlet channel and into the forming cavity via the guide channel. When the lower punch undergoes axial displacement relative to the middle die, the lubricant entering the forming cavity is evenly distributed on the contact surface between the lower punch and the middle die wall. During the pressing process, the lubricant lubricates between the powder and the die, and between the lower punch and the die wall. Compared to existing technologies, this application eliminates the need to add lubricant to the powder, avoiding problems such as reduced porosity, decreased density, impaired performance, and uneven sintering shrinkage caused by adding internal lubricant. This contributes to the molding of high-density and uniformly sized pressed products.

[0007] Preferably, it further includes a mandrel inserted into the lower punch auxiliary connector, the mandrel passing through the lower punch along the axial direction to extend into the forming cavity, and a lubrication gap existing between the outer wall of the mandrel and the lower punch auxiliary connector, the lubrication gap being connected to the liquid inlet channel.

[0008] Preferably, the liquid inlet channel includes a direct current channel and a circulating channel. One end of the direct current channel is connected to the outside, and the other end of the direct current channel is connected to the circulating channel. The lower end of the lower punch and the lower punch auxiliary connector form the circulating channel centered on the mandrel. The circulating channel is connected to the guide channel and the lubrication gap.

[0009] Preferably, the circulation channel is formed by an annular groove formed on the lower punch auxiliary connector.

[0010] Preferably, the flow guiding channel includes an axial channel arranged along the axial direction of the lower punch and a radial channel arranged along the radial direction of the lower punch. One end of the axial channel is connected to the liquid inlet channel, and the other end of the axial channel is connected to one end of the radial channel. The other end of the radial channel leads to the outer peripheral surface of the lower punch.

[0011] Preferably, the sidewall of the axial channel has an outlet leading to the outer wall of the mandrel.

[0012] Preferably, the cross-sectional area of ​​the circulating channel is larger than the cross-sectional area of ​​the DC channel.

[0013] Preferably, it further includes an electrostatic generator for charging the lubricant and / or charging the intermediate mold, thereby causing the charged lubricant to adhere to the cavity wall of the molding cavity.

[0014] Preferably, a sealing ring is provided between the lower punch and the lower punch auxiliary connector to prevent lubricant leakage.

[0015] In summary, this application includes at least one of the following beneficial technical effects: Precise control of lubricant dosage: Through the liquid inlet channel and the guide channel, the lubricant can be accurately delivered to the molding cavity. The supply of lubricant can be precisely controlled according to the actual pressing requirements, avoiding the problems of decreased product density, reduced performance, and uneven compact density after sintering caused by the difficulty in accurately controlling the dosage when adding lubricant to powder in the traditional way. To improve product quality, the lubricant can be evenly distributed on the molding cavity wall through the guide channel, which can effectively improve the flowability and filling properties of the powder, make the compact density more uniform, and thus improve the tensile strength, hardness and other properties of the product. Extending mold lifespan is achieved by directly lubricating the mold wall, reducing friction between the powder and the mold wall, and decreasing mold wear during the pressing process. This extends the mold's lifespan and also makes operation simple and convenient, improving work efficiency and reducing production costs. Attached Figure Description

[0016] Figure 1 This is a cross-sectional view of the mold wall lubrication structure in an embodiment of this application.

[0017] Figure 2 This is a partial cross-sectional view of the mold wall lubrication structure in an embodiment of this application.

[0018] Figure 3 This is a partial cross-sectional view of the mold wall lubrication structure without the mandrel installed in the embodiment of this application.

[0019] Figure 4 yes Figure 2 Enlarged diagram of point A in the middle.

[0020] Figure 5 yes Figure 3 Enlarged diagram of point B in the middle.

[0021] Explanation of reference numerals in the attached drawings: 1. Upper die punch; 2. Middle die; 3. Lower die punch; 4. Mandrel assembly; 21. Forming cavity; 31. Lower punch; 32. Lower punch auxiliary connector; 321. Liquid inlet channel; 311. Flow guide channel; 41. Mandrel; 42. Mandrel auxiliary connector; 322. First mandrel hole; 312. Second mandrel hole; 33. Lubrication gap; 323. Direct flow channel; 324. Circulation channel; 313. Axial channel; 314. Radial channel; 5. Sealing ring. Detailed Implementation

[0022] The following is in conjunction with the appendix Figure 1-5 This application will be described in further detail.

[0023] This application discloses a mold wall lubrication structure. (Refer to...) Figure 1 and Figure 2The mold wall lubrication structure includes an upper die punch 1, a middle die 2, a lower die punch 3, and a mandrel assembly 4. The middle die 2 has a forming cavity 21 extending through both ends, which is filled with powder for forming products. The upper die punch 1 and the lower die punch 3 can move vertically up and down to press the powder in the forming cavity 21. One end of the mandrel assembly 4 passes through the lower die punch 3 and extends into the forming cavity 21 to facilitate the forming of the inner hole of the product. The lower die punch 3 includes a lower punch head 31 and a lower punch auxiliary connector 32. The lower punch head 31 is fixedly mounted on the lower punch auxiliary connector 32, which has a liquid inlet channel 321 that communicates with the outside for delivering lubricant. The lower punch 31 is provided with a flow channel 311. One end of the flow channel 311 is connected to the liquid inlet channel 321, and the other end of the flow channel 311 is connected to the forming cavity 21. The lubricant flows from the liquid inlet channel 321 through the flow channel 311 and into the forming cavity 21. When the lower die punch 3 moves upward, the lubricant is evenly distributed between the contact surfaces of the outer wall of the lower punch 31 and the wall of the forming cavity 21, thereby achieving lubrication between the lower punch 31 and the inner wall of the middle die 2.

[0024] Reference Figure 2 and Figure 3 The mandrel assembly 4 includes a mandrel 41 and a mandrel auxiliary connector 42. The mandrel 41 is fixedly connected to the mandrel auxiliary connector 42. The lower die punch 3 has a mandrel hole for the mandrel 41 to pass through, and the mandrel hole is connected to the molding cavity 21. One end of the mandrel 41 passes through the mandrel hole and sequentially passes through the lower die auxiliary connector 32 and the lower die punch 31 to extend into the molding cavity 21. The corresponding mandrel hole on the lower die auxiliary connector 32 is the first mandrel hole 322, and the corresponding mandrel hole on the lower die punch 31 is the second mandrel hole 312. There is a lubrication gap 33 between the outer wall of the mandrel 41 and the lower die auxiliary connector 32. The lubrication gap 33 is connected to the liquid inlet channel 321. Lubricant flows from the liquid inlet channel 321 into the lubrication gap 33 to lubricate the outer wall of the mandrel 41 and reduce the friction between the outer wall of the mandrel 41 and the lower die auxiliary connector 32. In one embodiment, the diameter of the first mandrel hole 322 is 0.02 mm to 0.1 mm larger than the outer diameter of the mandrel 41. The gap between the inner wall of the first mandrel hole 322 and the outer wall of the mandrel 41 forms a lubrication gap 33. The width of the one-sided lubrication gap 33 formed between the inner wall of the first mandrel hole 322 and the outer wall of the mandrel 41 is 0.01 mm to 0.05 mm.

[0025] Reference Figure 2 and Figure 4The inlet channel 321 includes a direct flow channel 323 and a circulating flow channel 324. One end of the direct flow channel 323 is connected to the outside for conveying lubricant, and the other end of the direct flow channel 323 is connected to the circulating flow channel 324. The circulating flow channel 324 is located between the lower end of the lower punch 31 and the lower punch auxiliary connector 32. The circulating flow channel 324 is centered on the mandrel 41 and is connected to the first mandrel hole 322. The end of the first mandrel hole 322 is located at the center of the circulating flow channel 324. The circulating flow channel 324 is used to uniformly distribute the lubricant circumferentially. The circulating flow channel 324 is located axially between the lubrication gap 33 and the inlet of the guide channel 311. The circulating flow channel 324 is configured as a unified distribution cavity and is connected to both the inlet of the lubrication gap 33 and the inlet of the guide channel 311. The lubricant can flow evenly into the lubrication gap 33 and the guide channel 311 through the uniform circumferential distribution of the circulating flow channel 324. Preferably, the cross-sectional area of ​​the circulating channel 324 is larger than that of the direct current channel 323. As a lubricant distribution chamber, the larger cross-sectional area of ​​the circulating channel 324 ensures that the lubricant is smoothly and evenly distributed to the guide channel 311 and the lubrication gap 33, reducing the risk of localized lubrication failure due to uneven flow. One implementation of the circulating channel 324 is to have an annular groove on the lower punch auxiliary connector 32, forming the circulating channel 324. The first mandrel hole 322 is located at the center of the annular groove and communicates with it.

[0026] Reference Figure 3 and Figure 5 The flow channel 311 includes an axial channel 313 and a radial channel 314. The axial channel 313 is arranged along the axial direction of the lower punch 31, and the radial channel 314 is arranged along the radial direction of the lower punch 31. One end of the axial channel 313 is connected to the annular channel 324, and the other end of the axial channel 313 is connected to the radial channel 314. The other end of the radial channel 314 extends to the outer peripheral surface of the lower punch 31. Lubricant is distributed into the axial channel 313 through the annular channel 324, and then flows to the cavity wall of the forming cavity 21 through the radial channel 314 for lubrication. In a preferred embodiment, the side wall of the axial channel 313 has an outlet leading to the outer wall of the mandrel 41, so that the lubricant can flow to the outer wall of the mandrel 41 through the outlet of the side wall of the axial channel 313, thereby simultaneously lubricating the outer wall of the mandrel 41. Axial channels 313 can be provided in one form or symmetrically arranged on both sides of the mandrel 41. Radial channels 314 can be provided in one form or multiple forms. Providing multiple radial channels 314 that are evenly distributed circumferentially can ensure that the lubricant can be evenly and comprehensively delivered to the inner wall of the middle mold 2.

[0027] Reference Figure 1The mold wall lubrication structure also includes an electrostatic generator and a lubrication drive device (shown in text in the figure). The electrostatic generator is used to charge the lubricant and / or the intermediate mold 2, enhancing mold wall lubrication through electrostatic adsorption. Before powder pressing, the lubricant is pre-adsorbed evenly and firmly onto the inner wall of the intermediate mold 2 through electrostatic action, which can reduce the amount of lubricant used while obtaining excellent lubrication effect, ultimately significantly improving the density and uniformity of the pressed blank. The lubrication drive device is connected to the liquid inlet channel 321 for conveying and driving the flow of lubricant.

[0028] Reference Figure 3 A sealing ring 5 is provided between the lower punch 31 and the lower punch auxiliary connector 32. The sealing ring 5 is located on the outer periphery of the connection between the outlet of the liquid inlet channel 321 and the inlet of the circulation channel 324 to prevent lubricant leakage.

[0029] The implementation principle of the mold wall lubrication structure in this application embodiment is as follows: Before powder pressing, external lubricant enters the circulating channel 324 through the DC channel 323 under the action of the lubrication drive device. After being split by the circulating channel 324, it enters the guiding channel 311 and the lubrication gap 33 respectively. Under the action of the electrostatic generator, a uniform and firm lubricating film is pre-formed on the cavity wall of the forming cavity 21 and the outer wall of the mandrel 41. At the same time, the outlet of the side wall of the axial channel 313 allows the lubricant to flow to the outer wall of the mandrel 41. When the upper die punch 1 moves downward to press the powder, the lubricating film on the cavity wall of the forming cavity 21 reduces the friction between the powder and the inner wall of the middle die 2, reducing the consumption of pressing force. The lubricating film on the outer wall of the mandrel 41 reduces the friction between the powder and the mandrel 41, preventing the inner hole of the pressed blank from cracking due to friction, and at the same time reducing the wear of the mandrel 41. After pressing, the upper die punch 1 returns to its original position, and the lower punch 31 moves upward to eject the pressed blank. The lubricating film on the wall of the forming cavity 21 reduces the demolding friction between the pressed blank and the inner wall of the middle die 2, preventing the pressed blank from deforming during demolding. The lubricating film on the outer wall of the mandrel 41 prevents the inner hole of the pressed blank from sticking to the mandrel 41, ensuring that the pressed blank can smoothly detach from the mandrel 41.

[0030] The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A mold wall lubrication structure, comprising an upper mold punch (1), a middle mold (2), and a lower mold punch (3), wherein the middle mold (2) is provided with a forming cavity (21) penetrating both ends of the middle mold (2), characterized in that: The lower punch (3) includes a lower punch auxiliary connector (32) and a lower punch head (31) fixedly installed on the lower punch auxiliary connector (32). The lower punch auxiliary connector (32) is provided with a liquid inlet channel (321) communicating with the outside. The lower punch head (31) is provided with a flow guide channel (311). One end of the flow guide channel (311) is connected to the liquid inlet channel (321), and the other end of the flow guide channel (311) is connected to the forming cavity (21).

2. The mold wall lubrication structure according to claim 1, characterized in that: It also includes a mandrel (41) that is fitted into the lower punch auxiliary connector (32). The mandrel (41) passes through the lower punch (31) axially to extend into the forming cavity (21). There is a lubrication gap (33) between the outer wall of the mandrel (41) and the lower punch auxiliary connector (32). The lubrication gap (33) is connected to the liquid inlet channel (321).

3. The mold wall lubrication structure according to claim 2, characterized in that: The liquid inlet channel (321) includes a direct flow channel (323) and a circulating flow channel (324). One end of the direct flow channel (323) is connected to the outside, and the other end of the direct flow channel (323) is connected to the circulating flow channel (324). The lower end of the lower punch (31) and the lower punch auxiliary connector (32) form the circulating flow channel (324) centered on the mandrel (41). The circulating flow channel (324) is connected to the guide channel (311) and the lubrication gap (33).

4. The mold wall lubrication structure according to claim 3, characterized in that: The circulation channel (324) is formed by an annular groove formed on the lower punch auxiliary connector (32).

5. The mold wall lubrication structure according to claim 3, characterized in that: The flow channel (311) includes an axial channel (313) arranged along the axial direction of the lower punch (31) and a radial channel (314) arranged along the radial direction of the lower punch (31). One end of the axial channel (313) is connected to the liquid inlet channel (321), and the other end of the axial channel (313) is connected to one end of the radial channel (314). The other end of the radial channel (314) leads to the outer peripheral surface of the lower punch (31).

6. The mold wall lubrication structure according to claim 5, characterized in that: The sidewall of the axial channel (313) has an outlet leading to the outer wall of the mandrel (41).

7. The mold wall lubrication structure according to claim 3, characterized in that: The cross-sectional area of ​​the circulating channel (324) is larger than that of the direct current channel (323).

8. The mold wall lubrication structure according to claim 1, characterized in that: It also includes an electrostatic generator for charging the lubricant and / or charging the intermediate mold (2), thereby causing the charged lubricant to adhere to the cavity wall of the molding cavity (21).

9. The mold wall lubrication structure according to claim 1, characterized in that: A sealing ring (5) is provided between the lower punch (31) and the lower punch auxiliary connector (32) to prevent lubricant leakage.

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