Powder metallurgy forming die and method of using same

Abstract

The application relates to a forming die for powder metallurgy and an application method thereof. A lower die is fixed, an upper die is moved upwards to a lower die to form a powder filling area in a lower opening of the upper die, after powder filling, the upper die is moved downwards to cover the upper opening of the upper die and then continues to move downwards to drive the upper die to move downwards synchronously until the upper die contacts the powder for one-way pressing, so that a final forming position of a blank is close to the upper opening of the upper die, then the upper die is moved upwards to release the blank. The whole demolding stroke is only the thickness of the blank, the demolding distance is short, the demolding force is small, the abrasion of the blank to the inner wall of the upper die in the demolding process can be effectively reduced, the generation of a reverse buckle can be effectively avoided, the repair frequency can be effectively reduced, and the service life of the die is prolonged.

Description

Technical Field

[0001] This invention relates to the field of forming mold technology, and in particular to forming molds for powder metallurgy and their application methods. Background Technology

[0002] Ceramic-reinforced aluminum matrix composites possess properties such as low density, high specific strength and stiffness, high thermal conductivity, wear resistance, and corrosion resistance, making them promising for applications in lightweight structural components. However, when these materials are used in powder metallurgy to fabricate lightweight structural components, the wear on the molds during the forming stage is severe. This is because traditional forming molds have a fixed female mold, with the upper mold moving downwards to accommodate the upper opening of the female mold and the lower mold moving upwards to accommodate the lower opening. The upper and lower molds compress the powder material in the middle section of the female mold. Since the final forming area of ​​the blank is where the pressure is highest and wear is most severe, uneven wear on the inner wall of the female mold leads to undercuts, which in turn cause the blank to crack and become unusable during demolding. Traditional forming molds require undercut repair after 1500-2000 uses; otherwise, the blank will crack and become unusable. Summary of the Invention

[0003] Therefore, it is necessary to provide a powder metallurgy forming die that can effectively reduce the frequency of die repair and extend the service life of the die.

[0004] A forming mold for powder metallurgy includes an upper mold, a female mold, and a lower mold arranged coaxially. The forming mold also includes a mold frame, which includes an upper template, a female template, and a lower template connected axially in series via guide pillars. The upper template is used to fix the upper mold, the female template is used to fix the female mold, and the lower template is used to fix the lower mold. A female mold cylinder is provided inside the lower template and is connected to the female template. The female mold cylinder is used to drive the female mold to move axially through the female template. After the mold is closed, the upper mold covers the upper opening of the female mold to close the upper opening of the female mold, and the lower mold is accommodated in the lower opening of the female mold to close the lower opening of the female mold.

[0005] In one embodiment, the forming mold further includes a core cylinder and a core connected to the core cylinder. The core cylinder is disposed in the lower mold plate, and the upper mold and the lower mold are respectively provided with channels for the axial movement of the core.

[0006] In one embodiment, the bottom surface of the upper mold includes a pressing area and an abutting area; after the mold is closed, the pressing area is accommodated in the upper opening of the female mold and is in clearance fit with the inner wall of the female mold, and the abutting area is in sealed contact with the top of the female mold.

[0007] In one embodiment, the inner wall of the female mold includes a first segment extending axially, a second segment extending outward at a deviation of 3°~5° from the axial direction, and a third segment extending axially, wherein the first segment, the second segment, and the third segment are connected in sequence; after the mold is closed, the lower mold is at least partially in close fit with the first segment, and the pressing area is in clearance fit with the third segment.

[0008] In one embodiment, the height of the second segment is 0-1 mm less than the thickness of the blank; the height of the third segment is 5-10 mm.

[0009] In one embodiment, after mold closing, the single-sided distance between the pressing area and the third segment is 0.5mm~0.7mm.

[0010] In one embodiment, the forming mold further includes an upper mold press for providing power to the upper mold.

[0011] In one embodiment, the overflow valve of the female mold cylinder is set to 10 to 15 times the weight of the female mold itself.

[0012] This application also provides a method for applying the forming die for powder metallurgy as described in any of the above claims, comprising the following steps:

[0013] The lower mold is fixed in place, and the female mold moves upward to be accommodated in the lower opening of the female mold, and the lower mold and the female mold enclose a powder filling area;

[0014] Powder is filled in the powder-filling area;

[0015] After the upper mold descends to cover the upper opening of the female mold, it continues to descend, driving the female mold to descend synchronously, until the upper mold contacts the powder and presses it to form a blank.

[0016] The upper and lower molds are depressurized to clamp the blank, and the female mold moves downward until the side wall of the blank is completely exposed;

[0017] The upper mold moves upward and detaches from the blank, removing the blank.

[0018] The aforementioned powder metallurgy forming mold has a fixed lower mold. The female mold moves upward until it is accommodated within the lower opening of the female mold, forming a powder-filling area. After powder filling, the upper mold moves downward until it covers the upper opening of the female mold and continues to move downward, driving the female mold to move downward synchronously until it contacts the powder for unidirectional pressing. This causes the final forming position of the blank to be close to the upper opening of the female mold. Then, the blank moves downward through the female mold until the sidewalls of the blank are completely exposed. The upper mold then moves upward, releasing the blank. The entire demolding stroke is only the thickness of the blank, the demolding distance is short, and the demolding force is small. This effectively reduces the wear of the blank on the inner wall of the female mold during demolding, thereby effectively avoiding undercuts, reducing the frequency of repairs, and extending the service life of the mold. Attached Figure Description

[0019] Figure 1 A three-dimensional structural schematic diagram of a forming mold for powder metallurgy according to one embodiment;

[0020] Figure 2 A cross-sectional schematic diagram of a powder metallurgy forming mold according to one embodiment.

[0021] Figure 3 This is a schematic diagram of the structure of the inner wall of the female mold of a powder metallurgy forming mold according to one embodiment. Detailed Implementation

[0022] To facilitate understanding of the present invention, a more comprehensive description is provided below, along with preferred embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0023] It should be noted that when a component is referred to as being "set" on another component, it can be directly on the other component or there may be an intervening component. When a component is considered to be "connected" to another component, it can be directly connected to the other component, or there may be an intervening component.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0025] Please see Figure 1 and 2 One embodiment of a powder metallurgy forming mold 10 includes an upper mold 12, a female mold 14, and a lower mold 16 coaxially arranged. The forming mold also includes a mold frame 18, which includes an upper template 182, a female template 184, and a lower template 186 connected axially in series via guide posts 180. The upper template 182 is used to fix the upper mold 12, the female template 184 is used to fix the female mold 14, and the lower template 186 is used to fix the lower mold 16. A female mold cylinder 140 is provided inside the lower template 186, which is connected to the female template 184 and is used to drive the female mold 14 to move axially via the female template 184. After mold closing, the upper mold 12 covers the upper opening of the female mold 14 to close it, and the lower mold 16 is accommodated within the lower opening of the female mold 14 to close it.

[0026] It should be noted that in this embodiment, the lower template 186 is fixed, therefore the lower mold 16, which is fixed by the lower template 186, is also fixed. The forming mold 10 described above completes unidirectional pressing by controlling the upper mold 12 and the female mold 14 to move synchronously relative to the lower mold 16.

[0027] It is understood that the forming mold 10 also includes an upper mold press (not shown) for providing power to the upper mold 12.

[0028] Furthermore, guide post holes are pre-set at the four corners of the upper template 182, the female template 184, and the lower template 186. There are four guide posts 180, and each guide post passes through the guide post holes at the corresponding corners of the upper template 182, the female template 184, and the lower template 186 in sequence to form a cubic or cuboid spatial frame to ensure the stability and coaxiality of each template.

[0029] In this embodiment, the forming mold 10 further includes a core cylinder 190 and a core 19 connected to the core cylinder 190. The core cylinder 190 is disposed in the lower mold plate 186, and the upper mold 12 and the lower mold 16 are respectively provided with channels for the axial movement of the core 19 (not shown in the figure).

[0030] During pressing, the core column 19 is housed within the channels of the upper mold 12 and the lower mold 16, allowing the core column 19 to move axially, thus forming a blank with a central hole. After pressing is completed, the core column cylinder 19 is activated to drive the core column 19 out of the channels.

[0031] It is understandable that if it is not necessary to form a blank with a central hole, the aforementioned core column 19 and core column cylinder 190 can be omitted.

[0032] Furthermore, the bottom surface of the upper mold 12 includes a pressing area (not shown in the figure) and an abutting area (not shown in the figure). After the mold is closed, the pressing area is accommodated in the upper opening of the female mold 14 and is fitted with the inner wall of the female mold 14 with a gap. The abutting area is in sealed contact with the top of the female mold 14 so that the upper mold 12 can drive the female mold 14 to move down synchronously. Thus, when the pressing area of ​​the upper mold 12 contacts the powder for pressing, it is always in the position of the upper opening of the female mold 14.

[0033] It is understandable that the shape of the pressing area of ​​the upper mold 12 is adapted to the shape of the blank surface.

[0034] For further details, please refer to Figure 3 The inner wall of the female mold 14 includes a first segment 141 extending along the axial direction, a second segment 142 extending outward at a deviation of 3°~5° from the axial direction, and a third segment 143 extending along the axial direction. The first segment 141, the second segment 142, and the third segment 143 are connected in sequence.

[0035] After mold closing, the lower mold 16 is at least partially tightly fitted with the first section 141 to prevent powder leakage and wear on the female mold 14 and the lower mold 16. The pressing area is clearance-fitted with the third section 143, with a single-sided distance of 0.5mm~0.7mm between the pressing area and the third section 143, to ensure the sealing of the upper mold 12 while preventing incomplete powder removal that could lead to insufficient stroke of the upper mold 12. The second section 142 extends outward from the axial direction by 3°~5° to form a draft angle area, preventing undercut and reducing the demolding force during demolding.

[0036] Furthermore, the height of the second section 142 is 0-1mm less than the thickness of the blank, and the height of the third section 143 is 5-10mm, so that the area of ​​the second section 142 covers the entire undercut part.

[0037] Furthermore, the overflow valve of the female mold cylinder 140 is set to 10 to 15 times the weight of the female mold 14 to ensure that the female mold 14 will not fall automatically. Only the upper mold 12 contact area with the female mold 14. When the upper mold 12 presses against the female mold 14 and reaches the overflow pressure, the overflow valve opens, and the female mold 14 moves downward synchronously with the upper mold 12.

[0038] The specific application method of the above-mentioned forming mold 10 includes the following steps S110~S150:

[0039] S110, with the lower mold 16 fixed, the female mold cylinder 140 is started to drive the female template 184 to move upward, which in turn drives the female mold 14 to move upward to the lower mold 16 to be accommodated in the lower opening of the female mold 14. The lower mold 16 and the female mold 14 enclose each other to form a powder filling area.

[0040] S120. Fill the powder area as described above.

[0041] S130. Start the upper mold press and drive the upper mold 12 to descend until it covers the upper opening of the female mold 14. Continue to descend, driving the female mold 14 to descend synchronously until the upper mold 12 contacts the powder and is pressed to form a blank.

[0042] It is understandable that since the upper mold 12 covers the upper opening of the female mold 14, the upper mold 12 and the female mold 14 move down synchronously and press in one direction relative to the lower mold 16, so that the forming area is always at the upper opening of the female mold 14, and thus the subsequent demolding stroke is only the thickness of the blank, greatly reducing the demolding distance, thereby greatly reducing the wear of the blank on the inner wall of the female mold.

[0043] S140, upper mold 12 and lower mold 16 release pressure to clamp the blank, and female mold 14 moves downward until the side wall of the blank is completely exposed.

[0044] It is understandable that the upper mold 12 and the lower mold 16 release pressure to clamp the blank, so that when the female mold 14 moves downward to remove the blank from the side wall, the blank is protected from being torn during the removal process.

[0045] S150, the upper mold 12 moves upward and detaches from the blank, and the blank can be removed.

[0046] The above-described method of applying the forming mold enables protective demolding, solving the problem of cracking and scrapping of the formed blank during the demolding process. The final forming position of the blank is located in the upper area of ​​the female mold 14, the demolding stroke is only the thickness of the blank, the demolding distance is short, the demolding force is small, and the damage to the blank during the demolding process is minimized.

[0047] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A forming die for powder metallurgy, comprising an upper die, a female die, and a lower die arranged coaxially, characterized in that, The forming mold further includes a mold frame, which includes an upper mold plate, a female mold plate, and a lower mold plate connected axially in sequence via guide pillars. The upper mold plate is used to fix the upper mold, the female mold plate is used to fix the female mold, and the lower mold plate is used to fix the lower mold. A female mold cylinder is provided inside the lower mold plate and is connected to the female mold plate. The cylinder is used to drive the female mold to move axially through the female mold plate. After the mold is closed, the upper mold covers the upper opening of the female mold to close the upper opening, and the lower mold is accommodated in the lower opening of the female mold to close the lower opening. The bottom surface of the upper mold includes a pressing area and an abutting area. After the mold is closed, the pressing area is accommodated in the upper opening of the female mold and has a clearance fit with the inner wall of the female mold. The abutting area is in tight contact with the top of the female mold. The inner wall of the female mold includes a first section extending axially, a second section extending outward at a deviation of 3°~5° from the axial direction, and a third section extending axially. The first, second, and third sections are connected in sequence. After the mold is closed, the lower mold is at least partially in tight fit with the first section, and the pressing area has a clearance fit with the third section.

2. The forming die for powder metallurgy according to claim 1, characterized in that, The forming mold also includes a core cylinder and a core connected to the core cylinder. The core cylinder is disposed in the lower mold plate. The upper mold and the lower mold are respectively provided with channels for the axial movement of the core.

3. The forming die for powder metallurgy according to claim 1, characterized in that, The height of the second section is 0-1 mm less than the thickness of the blank; the height of the third section is 5-10 mm.

4. The forming die for powder metallurgy according to claim 1, characterized in that, After the mold is closed, the distance between the pressing area and the third segment on one side is 0.5mm~0.7mm.

5. The forming die for powder metallurgy according to claim 1, characterized in that, The forming mold also includes an upper mold press for providing power to the upper mold.

6. The forming die for powder metallurgy according to claim 1, characterized in that, The overflow valve setting of the female mold cylinder is 10 to 15 times the weight of the female mold itself.

7. A method for applying a forming die for powder metallurgy as described in any one of claims 1 to 6, characterized in that, Includes the following steps: The lower mold is fixed in place, and the female mold moves upward to be accommodated in the lower opening of the female mold, and the lower mold and the female mold enclose a powder filling area; Powder is filled in the powder-filling area; After the upper mold descends to cover the upper opening of the female mold, it continues to descend, driving the female mold to descend synchronously, until the upper mold contacts the powder and presses it to form a blank. The upper and lower molds are depressurized to clamp the blank, and the female mold moves downward until the side wall of the blank is completely exposed; The upper mold moves upward and detaches from the blank, removing the blank.

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