Upset-extruding machining method for high-precision U-shaped metal piece

Abstract

The invention relates to the technical field of metal processing, in particular to a high-precision U-shaped metal part upsetting-extruding processing method which comprises the following steps: S1, raw material selection; s2, punching the raw materials; s3, the unfolded plate of the U-shaped metal part is bent and machined; s4, the U-shaped metal piece blank is subjected to primary shaping; s5, upsetting and extruding the U-shaped metal piece blank; and S6, the U-shaped metal part is subjected to secondary shaping and slitting blanking. According to the upsetting-extruding forming mode and the upsetting-extruding structure of the high-precision U-shaped metal part, upsetting-extruding machining can be conducted on the bent edge of the U-shaped metal part in the production process of the U-shaped metal part, then the R angle of the bent edge of the U-shaped metal part is reduced, the use area of the straight end of the U-shaped metal part is increased, and then the product performance of the part is improved; according to the punching station, the rough cutting station and the fine cutting station are adopted for twice punching, so that the abrasion of the die can be reduced, and the punching precision of the unfolded plate of the U-shaped metal part is improved.

Description

Technical Field

[0001] The invention relates to the technical field of metal processing, in particular to a high-precision U-shaped metal part upsetting processing method. Background Art

[0002] Existing U-shaped metal parts, such as Figure 1-2 As shown, it is mostly formed by a sheet metal bending process, in which the base material to be processed is punched, bent, shaped, and blanked to obtain a finished U-shaped metal part.

[0003] The bending edge of the U-shaped metal part after bending will have a certain angle of R. However, the R angle of the bending edge of the U-shaped metal part formed by the sheet metal bending process is uncontrollable under the action of the bending force. For some high-precision U-shaped metal parts that rely on the outer area of ​​the part, the larger the bending edge of the U-shaped metal part, the smaller the straight end area that can be used, and the worse the product performance. Therefore, in order to improve the area utilization rate of the vertical and horizontal sections on the outer side of the high-precision U-shaped metal part, it is necessary to shape the R angle of the bending edge of the U-shaped metal part.

[0004] At the same time, there are still problems in the existing U-shaped metal parts forming process: first, the structure of the U-shaped metal parts will rebound after forming, which will affect the subsequent use of the U-shaped metal parts; secondly, the size of the blank before the U-shaped metal parts is bent will have a certain error after bending, which will affect the product quality of the U-shaped metal parts. Summary of the invention

[0005] The present invention adopts the following technical scheme to solve the above technical problems, a high-precision U-shaped metal part upsetting processing method, comprising the following steps: S1, raw material selection: select an appropriate strip plate according to the thickness of the U-shaped metal part, and cut the strip plate.

[0006] S2. Punching of raw materials: Place the cut strip sheet on a stepping conveyor, which moves the strip sheet to a punching station. The position of the strip sheet corresponding to the punching station is recorded as a U-shaped metal part forming area. The punching machine at the punching station punches the strip sheet to form an unfolded sheet of a U-shaped metal part in the U-shaped metal part forming area.

[0007] S3. Bending process: The strip plate after punching is transferred to the bending station by a stepping conveyor. The bending machine in the bending station is used to bend the unfolded sheet of the U-shaped metal part to obtain a U-shaped metal part blank.

[0008] S4, primary shaping: The U-shaped metal blank on the strip plate is transferred to the extrusion shaping machine of the primary shaping station by a stepping conveyor for primary extrusion shaping.

[0009] S5. Upsetting treatment: The U-shaped metal blank formed on the strip plate is transferred to the upsetting station by a stepping conveyor. The upsetting die on the upsetting station is used to upset the U-shaped metal blank. After upsetting, the outer R angle of the U-shaped metal part is reduced, increasing the usable area of ​​the straight end of the U-shaped metal part.

[0010] S6, secondary shaping and slitting and blanking: The U-shaped metal parts on the strip plate are transferred to the secondary shaping station by a stepping conveyor for secondary extrusion shaping, and then cut and blanked by a slitting machine at the slitting and blanking station.

[0011] Preferably, the punching station in step S2 includes a rough cutting station and a fine cutting station, and the rough cutting station and the fine cutting station are arranged side by side along the conveying direction of the strip plate.

[0012] Preferably, the fine-cutting station performs fine-cutting on the strip-shaped plate after rough-cutting, and the size of the unfolded plate of the U-shaped metal part after fine-cutting is larger than the unfolded size of the finished U-shaped metal part.

[0013] Preferably, the difference between the size of the unfolded sheet material of the precision-cut U-shaped metal part and the unfolded size of the finished U-shaped metal part is half the thickness of the strip plate.

[0014] Preferably, the punching station, bending station, primary shaping station, upsetting station, secondary shaping station, and slitting and blanking stations are arranged in sequence along the conveying direction of the strip plate, and the distances between adjacent punching stations, bending station, primary shaping station, upsetting station, secondary shaping station, and slitting and blanking stations are integer multiples of the U-shaped metal part forming area. After the stepping conveyor drives the strip plate to move, the punching station, bending station, primary shaping station, upsetting station, secondary shaping station, and slitting and blanking stations at corresponding positions respectively perform corresponding processing operations on the strip plate.

[0015] Preferably, the bending station in step S3 includes a 45-degree bending station and a 90-degree bending station, which are arranged side by side along the conveying direction of the strip plate, and the 45-degree bending station and the 90-degree bending station respectively bend the unfolded sheet of the U-shaped metal part at 45 degrees and 90 degrees.

[0016] Preferably, the upsetting die in step S5 includes an upsetting upper die and an upsetting lower die, the upsetting upper die includes an upper die seat, an upper pad, a fixed plate, a height limiting plate and an upper concave template which are sequentially installed on the lower side of the upper die seat, a fixed plate insert is arranged in the fixed plate, the upsetting punch is connected to the fixed plate through the fixed plate insert, an upsetting unloading plate pressure insert is installed in the upper concave template through an upsetting unloading plate pressure insert seat, a stripping ejector rod is installed on the upper die seat, and the stripping ejector rod passes through the upper pad, the fixed plate, the height limiting plate and the upper concave template; the upsetting lower die includes a lower die seat, a lower pad and a lower concave template which are sequentially installed on the lower die seat, and an upsetting concave template is installed in the lower concave template through an upsetting concave die pressure insert seat.

[0017] Preferably, the specific processing method of the upsetting die is as follows: during the downward movement of the upsetting upper die, the upsetting punch enters the upsetting die pressure insert seat, and a closed cavity is formed among the upsetting punch, the upsetting discharge plate pressure insert, the upsetting discharge plate pressure insert seat, and the upsetting die pressure insert; the downward extrusion of the upsetting punch causes the material of the bent edge of the U-shaped metal part to flow downward and be squeezed toward the R corner of the bent edge of the U-shaped metal part; at the same time, under the action of the upsetting discharge plate pressure insert and the upsetting die pressure insert, the R angle of the bent edge of the U-shaped metal part becomes smaller, and the usable area of ​​the straight end of the U-shaped metal part increases.

[0018] Preferably, the material of the upsetting punch is tungsten steel of model DC337, and the surface of the upsetting punch is provided with a coating.

[0019] Preferably, the surface coating of the upsetting punch is coated with a titanium carbide nitride coating by a physical vapor deposition method, and the coating thickness of the surface coating of the upsetting punch is 0.002-0.003 mm; the roughness is ≤Ra0.2.

[0020] The beneficial effects of the present invention are as follows: 1. The upsetting forming method and upsetting structure of the high-precision U-shaped metal part provided by the present invention can perform upsetting processing on the bent edge of the U-shaped metal part during the production process, thereby reducing the R angle of the bent edge of the U-shaped metal part, thereby increasing the use area of ​​the straight end of the U-shaped metal part, and thus improving the product performance of the part.

[0021] 2. The upsetting structure provided in the present invention forms a closed cavity between the four parts of the U-shaped metal part upsetting punch, the upsetting discharge plate pressing insert, the upsetting discharge plate pressing insert seat, and the upsetting die pressing insert. Under the downward extrusion action of the upsetting punch, the material of the bent edge of the U-shaped metal part flows downward and is squeezed toward the R corner of the bent edge of the U-shaped metal part, thereby increasing the area of ​​the straight end of the U-shaped metal part.

[0022] 3. The punching station set in the present invention adopts a two-time punching method of a rough cutting station and a fine cutting station to reduce the wear of the mold and improve the punching accuracy of the unfolded sheet of the U-shaped metal part; at the same time, the fine cutting allowance is set in the present invention to increase the dimensional accuracy of the U-shaped metal part after upsetting.

[0023] 4. The bending station provided in the present invention adopts a method of bending the unfolded sheet of the U-shaped metal part twice, thereby effectively preventing the rebound of the U-shaped metal part after bending, and increasing the forming effect of the U-shaped metal part; at the same time, the present invention can shape the structure of the U-shaped metal part after bending by one shaping of the blank, further increasing the stability of the U-shaped metal part and the later forming effect.

[0024] 5. The material of the upsetting punch of the present invention is tungsten steel of model DC337, which can increase the service life of the upsetting punch and the upsetting effect of the U-shaped metal part; at the same time, the surface coating of the upsetting punch is coated with titanium carbide nitride coating by physical vapor deposition method, which can further reduce the wear of the upsetting punch. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0026] Figure 1 It is a step diagram of the upsetting and extruding method of a high-precision U-shaped metal part according to the present invention.

[0027] Figure 2 It is a front view of the U-shaped metal part of the present invention.

[0028] Figure 3 It is a top view of the U-shaped metal part of the present invention.

[0029] Figure 4 It is a schematic diagram of processing at each workstation of the upsetting and extruding method of a U-shaped metal part of the present invention.

[0030] Figure 5 It is a schematic diagram of the precision cutting allowance in the forming area of ​​a U-shaped metal part of the present invention.

[0031] Figure 6 It is a schematic diagram of the upsetting structure of the present invention.

[0032] Figure 7 yes Figure 6 A partial enlarged view of point A in the middle. DETAILED DESCRIPTION

[0033] 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.

[0034] See also Figure 1 and Figure 4 A high-precision U-shaped metal part upsetting and extrusion processing method includes the following steps: S1, raw material selection: selecting a suitable strip plate according to the thickness of the U-shaped metal part, and cutting the strip plate into a size matching the U-shaped metal part. The present invention selects a strip plate to facilitate continuous forming processing, so that a plurality of U-shaped metal parts are formed on the strip plate along its length direction.

[0035] S2. Punching of raw materials: Place the strip sheet after cutting on the stepping conveyor, and drive the strip sheet to the punching station through the stepping conveyor. The position of the strip sheet corresponding to the punching station is recorded as the U-shaped metal part forming area. The punching machine at the punching station punches the strip sheet, so that the excess metal material in the U-shaped metal part forming area is removed, and the unfolded sheet of the U-shaped metal part is formed in the U-shaped metal part forming area. It can be understood that the unfolded sheet of the U-shaped metal part is connected to the strip sheet through the unpunched metal material, so that the unfolded sheet of the U-shaped metal part moves synchronously with the strip sheet, which facilitates the subsequent processing of the unfolded sheet of the U-shaped metal part in sequence.

[0036] See also Figure 3 The punching station in step S2 includes a rough cutting station and a fine cutting station, the rough cutting station and the fine cutting station are arranged side by side along the conveying direction of the strip plate, and the fine cutting station performs fine cutting on the strip plate after rough cutting. The present invention adopts the method of punching twice in the rough cutting station and the fine cutting station to reduce the wear of the mold and improve the punching accuracy of the unfolded sheet of the U-shaped metal part.

[0037] It should be noted that, see Figure 5 The size of the unfolded sheet of the U-shaped metal part after precision cutting is larger than the unfolded size of the finished U-shaped metal part, and the difference between the size of the unfolded sheet of the U-shaped metal part after precision cutting and the size of the unfolded size of the finished U-shaped metal part is recorded as the precision cutting allowance. Figure 5 The distance between the two dotted lines is the finishing allowance, and Figure 5The dotted line structure is the size of the finished U-shaped metal part after unfolding; since the unfolded sheet of the U-shaped metal part needs to be subjected to upsetting and extrusion, and the material extruded at the R corner of the U-shaped metal part during the upsetting and extrusion process comes from the bending edge of the U-shaped metal part, the present invention sets the precision cutting allowance to increase the dimensional accuracy of the U-shaped metal part after upsetting and extrusion. Exemplarily, the size of the precision cutting allowance of the present invention is set to half the thickness of the strip plate.

[0038] S3. Bending processing of unfolded sheet metal of U-shaped metal parts: The strip sheet metal after punching is transferred to the bending station by a stepping conveyor. The bending machine in the bending station is used to bend the unfolded sheet metal of the U-shaped metal part so that the unfolded sheet metal of the U-shaped metal part is bent to form a U-shaped metal part blank.

[0039] The bending stations in step S3 include a 45-degree bending station and a 90-degree bending station, which are arranged side by side along the conveying direction of the strip plate, and the 45-degree bending station and the 90-degree bending station respectively bend the unfolded sheet of the U-shaped metal part at 45 degrees and 90 degrees. By bending the unfolded sheet of the U-shaped metal part twice, the rebound of the U-shaped metal part after bending can be effectively prevented, thereby increasing the forming effect of the U-shaped metal part.

[0040] S4, primary shaping of the U-shaped metal blank: The U-shaped metal blank on the strip plate is transferred to the position of the extrusion shaping machine of the primary shaping station by a stepping conveyor for primary extrusion shaping. The primary shaping of the U-shaped metal blank by the present invention can shape its structure after bending, further increasing the stability of the U-shaped metal blank and the later forming effect.

[0041] S5. Upsetting of U-shaped metal blanks: The U-shaped metal blanks shaped on the strip plate are transferred to the upsetting station by a stepping conveyor. The upsetting die on the upsetting station is used to upset the U-shaped metal blanks. After upsetting, the outer R angle of the U-shaped metal part is reduced, increasing the usable area of ​​the straight end of the U-shaped metal part.

[0042] See also Figure 6 and Figure 7The upsetting die in step S5 includes an upsetting upper die 1 and an upsetting lower die 2. The upsetting upper die 1 includes an upper die seat 11, an upper pad 12, a fixed plate 13, a height limiting plate 14, and an upper concave die plate 15, which are sequentially installed on the lower side of the upper die seat 11. A fixed plate insert 16 is provided in the fixed plate 13. The upsetting punch 17 is connected to the fixed plate 13 through the fixed plate insert 16. The upper concave die plate 15 is connected to the fixed plate 13 through the upsetting discharge plate press insert seat. 18 is equipped with an upsetting unloading plate pressure insert 19, and a stripping ejector rod 10 is installed on the upper die base 11, and the stripping ejector rod 10 passes through the upper pad 12, the fixed plate 13, the height limit plate 14, and the upper concave template 15; the upsetting lower die includes a lower die base 21, a lower pad 22 and a lower concave template 23 which are sequentially installed on the lower die base 21, and an upsetting die pressure insert 25 is installed in the lower concave template 23 through an upsetting die pressure insert seat 24.

[0043] See also Figure 2 , Figure 6 and Figure 7 The specific processing method of the upsetting die is as follows: during the downward movement of the upsetting upper die 1, the upsetting punch 17 enters the upsetting die pressing insert seat 24, and a closed cavity is formed between the upsetting punch 17, the upsetting discharge plate pressing insert 19, the upsetting discharge plate pressing insert seat 18, and the upsetting die pressing insert 25. The downward extrusion of the upsetting punch 17 causes the material of the bent edge of the U-shaped metal part to flow downward and be squeezed toward the R angle of the bent edge of the U-shaped metal part. At the same time, under the action of the upsetting discharge plate pressing insert 19 and the upsetting die pressing insert 25, the R angle of the bent edge of the U-shaped metal part becomes smaller, and the use area of ​​the straight end of the U-shaped metal part increases. Figure 2 The middle vertical section is a bending edge, and the arc structure at the lower side of the bending edge is the R angle of the bending edge of the U-shaped metal part.

[0044] For example, in order to increase the service life of the upsetting punch 17, the material of the upsetting punch 17 is selected as tungsten steel of model DC337. In order to compare and verify the service life and upsetting effect of the upsetting punch 17, upsetting punches 17 made of SKD11, SKH-9, DC53, SKH-51, DC337, and MT312RM are selected for continuous upsetting tests. The experiment shows that after several upsetting treatments, the wear of DC337 tungsten steel is the smallest, which helps to increase the service life of the upsetting punch 17 and the upsetting effect of the U-shaped metal part.

[0045] Exemplarily, the surface of the upsetting punch 17 is provided with a coating, and the surface coating of the upsetting punch 17 is coated with a "titanium carbide (TiCN)-gray black" coating by a "physical vapor deposition (PVD)" method, and the coating thickness of the surface of the upsetting punch 17 is 0.0025 mm; the roughness is Ra0.16, and the coating shall not have defects such as pits, scratches, peeling, blistering, and wrinkling. By providing a coating on the surface of the upsetting punch 17, the wear of the upsetting punch 17 can be further reduced.

[0046] S6. Secondary shaping and slitting of U-shaped metal parts: The U-shaped metal parts on the strip plate are transferred to the secondary shaping station by a stepping conveyor for secondary extrusion shaping. After that, the U-shaped metal parts after secondary shaping are slitting and blanking by the slitting machine of the slitting and blanking station. The secondary shaping station is used to shape the U-shaped metal parts after the upsetting and extrusion process to increase the forming effect of the U-shaped metal parts.

[0047] The rough cutting station, fine cutting station, 45-degree bending station, 90-degree bending station, primary shaping station, upsetting station, secondary shaping station, and slitting and blanking stations are all arranged in sequence along the conveying direction of the strip plate, and the distances between the rough cutting station, fine cutting station, 45-degree bending station, 90-degree bending station, primary shaping station, upsetting station, secondary shaping station, and slitting and blanking stations are all integer multiples of the U-shaped metal part forming area. After the stepping conveyor drives the strip plate to move, the rough cutting station, fine cutting station, 45-degree bending station, 90-degree bending station, primary shaping station, upsetting station, secondary shaping station, and slitting and blanking stations at the corresponding positions respectively perform corresponding processing operations on the strip plate, so that the strip plate can be processed continuously.

[0048] It is understandable that since the existing U-shaped metal parts stamping and forming technology is relatively mature, stepping conveyors, punching and shearing machines, bending machines, extrusion shaping machines, and slitting machines have many applications in the processing direction of parts that need to be bent. The working principles and control methods of stepping conveyors, punching and shearing machines, bending machines, extrusion shaping machines, and slitting machines are all existing technologies, and the above-mentioned processing machines do not belong to the invention points of the present invention, so no excessive description will be made on the above-mentioned machines.

[0049] For example, see Figure 4 In the present invention, the spacing between the rough cutting station and the fine cutting station is one time the spacing between the U-shaped metal parts forming areas; the spacing between the fine cutting station and the 45-degree bending station is two times the spacing between the U-shaped metal parts forming areas; the spacing between the 45-degree bending station and the 90-degree bending station is one time the spacing between the U-shaped metal parts forming areas; the spacing between the 90-degree bending station and the primary shaping station is two times the spacing between the U-shaped metal parts forming areas; the spacing between the primary shaping station and the upsetting station is three times the spacing between the U-shaped metal parts forming areas; the spacing between the upsetting station and the secondary shaping station is three times the spacing between the U-shaped metal parts forming areas; and the spacing between the secondary shaping station and the slitting and blanking station is two times the spacing between the U-shaped metal parts forming areas.

[0050] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A high-precision U-shaped metal part upsetting method, characterized in that: The steps include: S1. Raw material selection: select suitable strip plates according to the thickness of the U-shaped metal parts, and cut the strip plates; S2. Punching of raw materials: placing the strip sheet after cutting on a stepping conveyor, and driving the strip sheet to the punching station through the stepping conveyor. The position of the strip sheet corresponding to the punching station is recorded as the U-shaped metal part forming area. The punching machine of the punching station punches the strip sheet, and the U-shaped metal part is formed in the U-shaped metal part forming area. S3, Bending processing: The strip plate after punching is transferred to the bending station by a stepping conveyor, and the bending machine of the bending station is used to bend the unfolded sheet of the U-shaped metal part to obtain a U-shaped metal part blank; S4, primary shaping: The U-shaped metal blank on the strip plate is transferred to the extrusion shaping machine of the primary shaping station by a stepping conveyor for primary extrusion shaping; S5, upsetting treatment: The U-shaped metal blank formed on the strip plate is transferred to the upsetting station by a stepping conveyor. The upsetting die on the upsetting station is used to upset the U-shaped metal blank. After upsetting, the outer R angle of the U-shaped metal part is reduced, increasing the use area of ​​the straight end of the U-shaped metal part. S6, secondary shaping and slitting and blanking: The U-shaped metal parts on the strip plate are transferred to the secondary shaping station by a stepping conveyor for secondary extrusion shaping, and then cut and blanked by a slitting machine at the slitting and blanking station.

2. A high-precision U-shaped metal part upsetting method according to claim 1, characterized in that: The punching station in step S2 includes a rough cutting station and a fine cutting station, and the rough cutting station and the fine cutting station are arranged side by side along the conveying direction of the strip plate.

3. A high-precision U-shaped metal part upsetting method according to claim 2, characterized in that: The fine cutting station performs fine cutting on the roughly cut strip-shaped plate, and the size of the unfolded plate of the finely cut U-shaped metal part is larger than the unfolded size of the finished U-shaped metal part.

4. A high-precision U-shaped metal part upsetting method according to claim 3, characterized in that: The difference between the size of the unfolded sheet material of the precision-cut U-shaped metal part and the unfolded size of the finished U-shaped metal part is half the thickness of the strip plate.

5. A high-precision U-shaped metal part upsetting method according to claim 1, characterized in that: The punching station, bending station, primary shaping station, upsetting station, secondary shaping station, and slitting and blanking stations are all arranged in sequence along the conveying direction of the strip plate, and the distances between adjacent punching stations, bending stations, primary shaping station, upsetting station, secondary shaping station, and slitting and blanking stations are all integer multiples of the U-shaped metal part forming area. After the stepping conveyor drives the strip plate to move, the punching station, bending station, primary shaping station, upsetting station, secondary shaping station, and slitting and blanking stations at corresponding positions perform corresponding processing operations on the strip plate respectively.

6. A high-precision U-shaped metal part upsetting method according to claim 1, characterized in that: The bending stations in step S3 include a 45-degree bending station and a 90-degree bending station, which are arranged side by side along the conveying direction of the strip plate, and the 45-degree bending station and the 90-degree bending station respectively bend the unfolded sheet of the U-shaped metal part at 45 degrees and 90 degrees.

7. A high-precision U-shaped metal part upsetting method according to claim 1, characterized in that: The upsetting die in step S5 comprises an upsetting upper die (1) and an upsetting lower die (2), wherein the upsetting upper die (1) comprises an upper die seat (11), an upper pad (12) sequentially mounted on the lower side of the upper die seat (11), a fixed plate (13), a height limiting plate (14), and an upper concave die plate (15), wherein a fixed plate insert (16) is arranged in the fixed plate (13), an upsetting punch (17) is connected to the fixed plate (13) via the fixed plate insert (16), and an upsetting discharge plate pressing insert seat (14) is arranged in the upper concave die plate (15). 18) is provided with an upsetting unloading plate pressure insert (19), a stripping ejector rod (10) is installed on the upper die seat (11), and the stripping ejector rod (10) passes through an upper pad (12), a fixing plate (13), a height limiting plate (14), and an upper concave template (15); the upsetting lower die comprises a lower die seat (21), a lower pad (22) and a lower concave template (23) which are sequentially installed on the lower die seat (21), and an upsetting concave template (23) is provided with an upsetting concave template (25) through an upsetting concave die pressure insert seat (24).

8. A high-precision U-shaped metal part upsetting method according to claim 7, characterized in that: The specific processing method of the upsetting die is as follows: when the upsetting upper die (1) is in the downward movement, the upsetting punch (17) enters the upsetting die pressing insert seat (24), and a closed cavity is formed between the upsetting punch (17), the upsetting discharge plate pressing insert (19), the upsetting discharge plate pressing insert seat (18), and the upsetting die pressing insert (25). The material of the bent edge of the U-shaped metal part flows downward due to the downward extrusion of the upsetting punch (17) and is squeezed toward the R angle of the bent edge of the U-shaped metal part. At the same time, under the action of the upsetting discharge plate pressing insert (19) and the upsetting die pressing insert (25), the R angle of the bent edge of the U-shaped metal part becomes smaller, and the use area of ​​the straight end of the U-shaped metal part increases.

9. A high-precision U-shaped metal part upsetting method according to claim 7, characterized in that: The material of the upsetting punch (15) is tungsten steel of model DC337, and a coating is arranged on the surface of the upsetting punch (15).

10. A high-precision U-shaped metal part upsetting method according to claim 9, characterized in that: The surface coating of the upsetting punch (15) is coated with a titanium carbide nitride coating by a physical vapor deposition method, and the surface coating of the upsetting punch (15) has a thickness of 0.002-0.003 mm and a roughness of ≤Ra0.2.

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