Clamping device for repairing punch blade edge of cold stamping die by laser cladding and repairing process

Abstract

The application discloses a clamping device and a repairing process for repairing a punch blade of a cold punch die by laser cladding. Specifically, the failed cold punch die punch is clamped on a three-jaw chuck, and the rotation speed of the repaired punch is controlled by a PC connected with a PLC. By changing the relative position of the sliding groove of the supporting frame on the base, the deflection angle of the repaired region of the punch and the laser head is adjusted to realize three kinds of repairing processes for the punch blade of the cold punch die. The cladding layers prepared on the repaired regions with an inclination angle of (0-60 DEG) by the three kinds of repairing processes are detected by a microhardness tester, and the applicable ranges of the processes for repairing the punch blade of the cold punch die are determined according to the measured hardness values.

Description

Technical Field

[0001] This invention relates to the field of laser cladding technology for repairing metal surfaces, and in particular to a clamping device and repair process for repairing the cutting edge of a cold stamping die punch after wear failure using laser cladding technology. Background Technology

[0002] During the stamping process, repeated extrusion and friction occur between the punch surface and the sheet metal. Therefore, punch edge wear is the main cause of stamping die failure, accounting for approximately 70% to 80% of all failures. When a punch fails due to wear, it is usually repaired using simple methods such as welding or simply scrapped, resulting in significant resource waste. Laser cladding technology has the advantages of relatively concentrated beam energy and a smaller heat-affected zone on the substrate. By using self-fluxing alloy powder combined with a reasonable repair process, it can not only effectively repair the damaged area of ​​the punch but also improve the overall performance of the repaired area and extend its service life. Since the punch is a rotating workpiece, laser cladding repair technology requires the workpiece to rotate to complete the repair. Moreover, the morphology of the damaged area of ​​the punch varies, so it is necessary to appropriately adjust the deflection angle between the area to be repaired and the laser head. Currently, there is no suitable repair device or method. In the context of today's society advocating the development of a circular economy and improving resource recycling efficiency, it is necessary to invent a clamping device and repair process for the punch edge of cold stamping dies that fails due to wear. Summary of the Invention

[0003] In order to overcome the shortcomings of the prior art, the present invention develops a clamping device and repair process for laser cladding repair of the cutting edge of the punch of a cold stamping die.

[0004] The technical solution of this invention is:

[0005] Design a clamping device and repair process for laser repair of the cutting edge of a cold stamping die punch. The device comprises a three-jaw chuck, a chuck base, an outer connecting plate, locking bolts, a support frame, fixing bolts, a locking nut, a base, a slide groove, a stop button, a start button, a 24V power converter, a driver, a stepper motor, and an S7-200 (PLC). The chuck base is connected to the three-jaw chuck and the outer connecting plate using locking bolts, and the support frame is connected to the outer connecting plate using fixing bolts. The relative angle between the punch to be repaired and the laser beam is changed by altering the relative position of the support frame within the slide groove on the base, and is secured by locking nuts. The 24V power converter, start button, and stop button are connected to the S7-200 (PLC). The S7-200 (PLC) controls the stepper motor via the driver to rotate the punch clamped on the three-jaw chuck. The rotation speed of the punch to be repaired is controlled by a PC connected to the S7-200 (PLC). Furthermore, when adjusting the angle between the laser head and the area to be repaired by the punch, a right-angle ruler is needed to ensure their relative positional relationship.

[0006] Furthermore, the laser head is always perpendicular to the ground (horizontal plane). By adjusting the relative position of the support frame in the chute, the area to be repaired by the punch is always kept perpendicular to the laser head.

[0007] Furthermore, the laser head is always perpendicular to the ground (horizontal plane). By adjusting the relative position of the support frame in the chute, the punch is kept horizontal to the ground (horizontal plane).

[0008] Furthermore, adjust the relative position of the support frame within the chute to keep the punch horizontal with respect to the ground (horizontal plane), and adjust the position of the laser head to keep it perpendicular to the area to be repaired by the punch.

[0009] The above three repair processes were used to clad the areas to be repaired at inclination angles of 0-60°. The hardness of the cladding layers was tested using a microhardness tester. The results showed that: the repair process where the laser head was always perpendicular to the ground (horizontal plane), and the relative position of the support frame in the chute was adjusted to keep the punch horizontal, produced cladding hardness values ​​that met the hardness requirements for cold stamping die punches when the inclination angle of the punch area to be repaired was less than 35°; the repair process where the laser head was always perpendicular to the ground (horizontal plane), and the relative position of the support frame in the chute was adjusted to keep the punch area to be repaired perpendicular to the laser head, produced cladding hardness values ​​that met the hardness requirements for cold stamping die punches; and the repair process where the relative position of the support frame in the chute was adjusted to keep the punch horizontal, and the laser head position was adjusted to keep it perpendicular to the punch area to be repaired, produced cladding hardness values ​​that met the hardness requirements for cold stamping die punches when the inclination angle of the punch area to be repaired was less than 50°. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the overall structure of the clamping device for laser cladding repair of the cutting edge of a cold stamping die according to the present invention;

[0011] Figure 2 This is a schematic diagram of the control process of the clamping device for laser cladding repair of the cutting edge of the cold stamping die punch according to the present invention;

[0012] Figure 3 This is a schematic diagram of the circuit connection of the clamping device for laser cladding repair of the cutting edge of a cold stamping die punch according to the present invention.

[0013] Figure 4The following is a schematic diagram of the process for repairing the cutting edge of a cold stamping die punch according to the present invention: (a) The laser head is always perpendicular to the ground (horizontal plane). By adjusting the relative position of the support frame in the slide groove, the punch is kept horizontal with respect to the ground (horizontal plane); (b) The laser head is always perpendicular to the ground (horizontal plane). By adjusting the relative position of the support frame in the slide groove, the area of ​​the punch to be repaired is always kept perpendicular to the laser head; (c) The relative position of the support frame in the slide groove is adjusted to keep the punch horizontal with respect to the ground (horizontal plane). By adjusting the position of the laser head, it is kept perpendicular to the area of ​​the punch to be repaired.

[0014] Figure 5 Microhardness values ​​of the cladding layer were prepared on the area to be repaired (0~60°) for three repair processes;

[0015] Figure 6 Comparison of three repair processes for repairing cold stamping die punches: (a) When the area to be repaired is 30°, the laser head is always perpendicular to the ground (horizontal plane), and the relative position of the support frame in the slide is adjusted to keep the punch horizontal with the ground (horizontal plane); (b) When the area to be repaired is 60°, the laser head is always perpendicular to the ground (horizontal plane), and the relative position of the support frame in the slide is adjusted to keep the area to be repaired of the punch perpendicular to the laser head; (c) When the area to be repaired is 50°, the relative position of the support frame in the slide is adjusted to keep the punch horizontal with the ground (horizontal plane), and the position of the laser head is adjusted to keep it perpendicular to the area to be repaired of the punch.

[0016] Figure 7 Metallographic images of the bonding area between the cladding layer and the substrate after repairing the punch of a cold stamping die using three repair processes: (a) When the area to be repaired is 30°, the laser head is always perpendicular to the ground (horizontal plane), and the relative position of the support frame in the slide is adjusted to keep the punch horizontal to the ground (horizontal plane); (b) When the area to be repaired is 60°, the laser head is always perpendicular to the ground (horizontal plane), and the relative position of the support frame in the slide is adjusted to keep the area to be repaired of the punch perpendicular to the laser head; (c) When the area to be repaired is 50°, the relative position of the support frame in the slide is adjusted to keep the punch horizontal to the ground (horizontal plane), and the position of the laser head is adjusted to keep it perpendicular to the area to be repaired of the punch.

[0017] In the diagram: 1. Punch to be repaired, 2. Three-jaw chuck, 3. Chuck seat, 4. Chuck external connecting plate, 5. Locking bolt, 6. Support frame, 7. Fixing bolt, 8. Locking nut, 9. Base, 10. Slide, 11. Stop button, 12. Start button, 13. 24V power converter, 14. Driver, 15. Stepper motor, 16. S7-200 (PLC). Detailed Implementation

[0018] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The specific process steps are as follows:

[0019] (1) The base material is a cold stamping die punch that failed due to edge wear. The cladding powder is Wc / Ni alloy powder with the composition shown in Table 1. The particle size of the powder is 20~50μm. The punch edge was pretreated using an FX-40 universal tool grinder according to the wear morphology. The cladding powder was dried for 8 hours before use.

[0020] Table 1 Chemical composition of WC / Ni powder and Cr12MoV cold work die steel

[0021] element C Si Mn B Cr Mo WC Ni Fe WC / Ni 1.12 0.42 0.42 3.5 8.05 0.84 25 margin / Cr12MoV 1.6 0.6 1.0 1.6 13.0 1.2 / / margin

[0022] (2) Laser cladding was performed using a KUKA robotic arm (model KR30) carrying a PERCITEC YC52 laser head. The laser used was an IPG YLR-3000 fiber laser. The powder feeder was a Beijing Feihong FHPF-10 synchronous powder feeder. The relationship between the powder feeding voltage and the powder feeding quality per minute is shown in Table 2. For ease of expression, the powder feeding amount in this paper is expressed in terms of powder feeding voltage. The laser spot diameter was 2.50 mm, the powder feeding gas (N2) pressure was 0.3 MPa, the carrier gas flow rate was 600 L / h, the protective gas (N2) pressure was 0.1 MPa, and the cladding parameters were as follows: laser power 1200 W, scanning speed 2 mm / s, powder feeding ignition 10 V, and defocusing amount (the straight-line distance between the laser head and the area to be repaired) 12 mm.

[0023] Table 2 Relationship between powder feeding voltage and powder feeding amount

[0024] Powder feeding voltage (V) 8 9 10 11 12 13 14 15 16 17 18 Powder delivery rate (g / min) 7 8 9 10 12 14 16 18 20 22 24

[0025] (3) A clamping device for laser repair of cold stamping die punches, including: punch to be repaired 1, three-jaw chuck 2, chuck seat 3, chuck outer connecting plate 4, locking bolt 5, support frame 6, fixing bolt 7, locking nut 8, base 9, slide 10, stop button 11, start button 12, 24V power converter 13, driver 14, stepper motor 15, S7-200 (PLC) 16. The deflection angle of the area to be repaired and the laser head of the punch 1 can be adjusted by changing the relative position of the support frame 6 on the slide 10 on the base 9, and the rotation speed of the punch to be repaired can be controlled by connecting the PLC 16 to the PC.

[0026] (4) The microhardness distribution of the cross section of the cladding layer was tested using an HVS-1000 microhardness tester. The sampling points were taken along the direction perpendicular to the center line of the cladding layer surface, with an interval of ±0.1 mm. The origin was set at a point 0.3 mm from the cladding layer surface. A total of 7 test points were used, and the average microhardness value was calculated. The test load was 100 g, and the loading time was 10 s. Test results show that: the hardness values ​​of the cladding layer prepared by the repair process in which the laser head is always perpendicular to the ground (horizontal plane) and the relative position of the support frame in the slide groove is adjusted to keep the punch horizontal to the ground (horizontal plane) all meet the hardness requirements of the cold stamping die punch; the hardness values ​​of the cladding layer prepared by the repair process in which the laser head is always perpendicular to the ground (horizontal plane) and the relative position of the support frame in the slide groove is adjusted to keep the punch horizontal to the ground (horizontal plane) when the tilt angle is less than 35° meet the hardness requirements of the cold stamping die punch; the hardness values ​​of the cladding layer prepared by the repair process in which the relative position of the support frame in the slide groove is adjusted to keep the punch horizontal to the ground (horizontal plane) and the position of the laser head is adjusted to keep it perpendicular to the area to be repaired by the punch when the tilt angle is less than 50° meet the hardness requirements of the cold stamping die punch.

[0027] (5) Through Figure 7 It can be seen that when the three repair methods are used to repair the cutting edge of the cold stamping die, the cladding (repair) layer prepared under reasonable process arrangement is very tightly bonded to the substrate, and a good transition is formed from the cladding (repair) layer to the substrate, without forming a relatively obvious microstructure boundary, indicating that a good metallurgical bond has been formed. During the solidification of the molten pool, because the temperature gradient increases towards the center of the molten pool, a large number of columnar equiaxed crystals are formed at the bonding area, pointing towards the center of the molten pool.

[0028] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A clamping device for laser repair of cold stamping die punches, characterized in that: The clamping device includes a three-jaw chuck, a chuck base, a chuck outer connecting plate, locking bolts, a support frame, fixing bolts, locking nuts, a base, a slide groove, a 24V power converter, a start button, a stop button, an S7-200 PLC, a driver, and a stepper motor. The chuck base is connected to the three-jaw chuck and the chuck outer connecting plate by locking bolts; the support frame is connected to the chuck outer connecting plate by fixing bolts, and the end of the support frame connected to the chuck extends out of the base. The base and the support frame are locked together by locking nuts. The deflection angle of the punch repair area and the laser head is adjusted by changing the relative position of the slide groove on the base. When adjusting the angle between the laser head and the punch repair area, a right-angle ruler is needed to ensure their relative positional relationship. The power converter, start button, and stop button are connected to the S7-200 PLC. The S7-200 PLC controls the stepper motor to rotate the punch clamped on the three-jaw chuck by connecting to the driver.

2. The clamping device for laser repair of cold stamping die punches according to claim 1, characterized in that: The groove is a quarter-circle arc.

3. A laser repair process for the cutting edge of a cold stamping die punch, applied to the clamping device for laser repair of cold stamping die punches as described in any one of claims 1-2, characterized in that: The specific process steps are as follows: (1) The base material is a cold stamping die punch that failed due to edge wear. The edge of the punch was pretreated by a universal tool grinder according to the wear morphology. The cladding powder is WC / Ni alloy powder. The cladding powder was dried for 8 hours before use. (2) The cold stamping die punch is clamped by the clamping device for laser repair of the cold stamping die punch, and the deflection angle of the punch repair area and the laser head is adjusted by changing the relative position of the slide groove on the base of the support frame. When adjusting the angle between the laser head and the punch repair area, a right angle ruler is needed to ensure their relative position relationship. The power converter, start button and stop button are connected to the S7-200PLC. The S7-200PLC controls the stepper motor to drive the punch clamped on the three-jaw chuck to rotate by connecting to the driver. The PC is connected to the S7-200PLC to control the rotation speed of the punch to be repaired. (3) A laser is used in conjunction with a powder feeder, and the laser head is carried by a robotic arm to perform laser cladding.

4. The laser repair process for the cutting edge of a cold stamping die punch according to claim 3, characterized in that: The laser head is always perpendicular to the horizontal plane. By adjusting the relative position of the support frame in the slide groove, the area to be repaired by the punch is always kept perpendicular to the laser head.

5. The laser repair process for the cutting edge of a cold stamping die punch according to claim 3, characterized in that: The laser head is always perpendicular to the horizontal plane. By adjusting the relative position of the support frame in the slide groove, the punch is kept horizontal to the horizontal plane.

6. The laser repair process for the cutting edge of a cold stamping die punch according to claim 3, characterized in that: Adjust the relative position of the support frame in the chute so that the punch is level with the horizontal plane, and adjust the position of the laser head so that it is perpendicular to the area to be repaired by the punch.

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