Machining process for thick punch of die for automobile precision part

Abstract

The invention relates to the technical field of die thick punch machining, and particularly discloses a die thick punch machining process for automobile precision parts, which comprises the following steps: 1, base material pretreatment: carrying out pre-heat treatment on a to-be-machined base material; secondly, a wire penetrating hole is machined, and the wire penetrating hole is machined in the pretreated base material; thirdly, clamping and fixing are conducted, specifically, the base material with the determined wire penetrating hole is clamped and fixed; fourthly, rough machining is conducted, specifically, rough machining is conducted on the clamped and fixed base material, and cutting treatment is conducted; 5, tempering treatment is conducted, specifically, the cut-off base material is subjected to heat preservation for 2 hours at the temperature of 180 DEG C; sixthly, secondary clamping is conducted, specifically, the tempered base material is clamped and fixed again through magnetic attraction and glue; seventhly, semi-finish machining is conducted, specifically, the base material which is clamped and fixed again is subjected to semi-finish machining; and eighthly, finish machining is conducted, specifically, finish machining cutting is conducted on the base material subjected to semi-finish machining. The precision and quality of the thick punch can be improved, the machining quality is improved, and the production cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of thick punch processing for molds, and specifically relates to a processing technology for thick punches of molds for automotive precision parts. Background Art

[0002] In precision automotive molds, the punch is one of the core components of the stamping die, mainly used to apply pressure to the metal sheet during stamping, causing it to undergo plastic deformation, separation or forming, so as to process the required parts (such as holes, bosses, cuts, etc.).

[0003] Slow wire electrical discharge machining occupies an important position in mold processing. Since it meets the requirements of the punch for dimensional consistency and wear resistance, currently, for the processing of punches made of high-hardness materials, most are processed by slow wire electrical discharge machining. However, for the processing of punches with extremely high thickness, there have always been problems such as large dimensional deviations between the upper, middle and lower parts, poor wire trace surface finish, and high defect rates, which add a lot of pressure to production and cost control and cannot meet production requirements. Summary of the Invention

[0004] Aiming at the defects of the above-mentioned existing technologies, the present invention provides a processing technology for thick punches of molds for automotive precision parts, which can effectively improve the accuracy and quality of thick punches, thereby extending the service life of stamping dies, reducing the number of die repairs, reducing costs, improving the processing quality of products, reducing production costs, and meeting production requirements.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A processing technology for thick punches of molds for automotive precision parts, comprising the following steps:

[0007] The first step, substrate pretreatment, pre-heat-treat the substrate to be processed to eliminate forging stress;

[0008] The second step, machining a wire threading hole, machining a wire threading hole on the pretreated substrate;

[0009] The third step, clamping and fixing, clamp and fix the substrate after determining the wire threading hole;

[0010] The fourth step, rough machining, rough machine the clamped and fixed substrate by a wire cutting machine according to a set cutting path, remove most of the surplus of the punch, and perform a cutting-off process;

[0011] The fifth step, tempering treatment, keep the substrate after cutting-off at 180 °C for 2 hours to eliminate cutting stress and improve toughness;

[0012] The sixth step, secondary clamping, re-clamp and fix the substrate after tempering treatment by magnetic attraction and glue;

[0013] The seventh step is semi-finishing. The re-clamped and fixed substrate is semi-finished by a wire cutting machine according to the set cutting path, leaving a finishing allowance.

[0014] The eighth step is finishing. The semi-finished substrate is finish-cut by a wire cutting machine to process the substrate into a punch that meets the final dimensional and precision requirements.

[0015] The ninth step is deburring and cleaning. For the finished punch, remove the burrs and flash on the surface to ensure that the edge of the punch is smooth and does not affect its use. Then wash the punch with clean water or a special cleaning liquid to remove impurities such as oil stains and chips on the surface, and then dry it with compressed air or put it in an oven to dry.

[0016] Preferably, the pre-heat treatment in the first step is stress-relieving annealing, keeping it at 650 °C for 4 hours, cooling in the furnace to 200 °C and then taking it out of the furnace to eliminate forging stress.

[0017] Preferably, the wire threading hole in the second step is machined and formed with a φ3mm cemented carbide drill bit.

[0018] Preferably, in the third step, upper and lower double-layer clamping plates are used for clamping and fixing.

[0019] Preferably, the number of rough machining cuts in the fourth step is two. The first cut: leave a 0.5mm allowance on each side. The second cut: leave a 0.3mm allowance on each side.

[0020] Preferably, in the sixth step, the substrate is adsorbed and positioned by a magnet fixture, and glue is coated on the edge where the substrate contacts the magnet fixture for auxiliary fixation.

[0021] Preferably, the number of semi-finishing cuts in the seventh step is two. The first cut: leave a 0.25mm allowance on each side. The second cut: leave a 0.08mm allowance on each side.

[0022] Preferably, the number of finishing cuts in the eighth step is three. The first cut: leave a 0.03mm allowance on each side. The second cut: leave a 0.02mm allowance on each side. The third cut: no allowance.

[0023] Preferably, after the ninth step, there is also a tenth step of quality inspection to check whether the size, surface integrity and hardness of the punch meet the requirements.

[0024] Preferably, after the quality inspection control in the tenth step, there is also an eleventh step of packaging and warehousing to package and warehouse the qualified punches.

[0025] The beneficial effects produced by the present invention are as follows: After rough machining, cutting treatment is carried out, and then the cut substrate is subjected to tempering treatment at 180°C for 2 hours to eliminate cutting stress and improve toughness. At the same time, during the second clamping, it is fixed by magnetic attraction and glue clamping, reducing stress deformation generated by punch cutting. This can effectively improve the precision and quality of thick punches, thereby extending the service life of stamping dies, reducing the number of die repairs, lowering costs, improving the processing quality of products, reducing production costs, and meeting production requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 : It is a schematic flow chart of an embodiment of the present invention; DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] To more clearly elaborate on the structural features, technical means, and the specific purposes and functions achieved by the present invention, the present invention will be further described in detail below in conjunction with the drawings and specific embodiments:

[0028] In this embodiment: As Figure 1 shown, a processing technology for thick punches of a mold for automotive precision parts includes the following steps:

[0029] The first step is substrate pretreatment. The substrate to be processed is subjected to pre-heat treatment. Through stress relief annealing, it is held at 650°C for 4 hours, cooled in the furnace to 200°C and then taken out of the furnace to eliminate forging stress;

[0030] The second step is to process the wire threading holes. Determine the positions of the wire threading holes on the pretreated substrate, and use a φ3mm cemented carbide drill to process the wire threading holes with a position accuracy of ±0.02mm and a depth that penetrates the workpiece;

[0031] The third step is clamping and fixing. The substrate after determining the wire threading holes is clamped and fixed. Double-layer upper and lower clamping plates are used for clamping and fixing. The bottom clamping plate is made of 30mm thick quenched and tempered steel and is fixed to the machine tool workbench through bolts with a flatness ≤0.005mm. The upper clamping plate is made of 15mm thick cemented carbide and is aligned with the bottom clamping plate through positioning pins to avoid machining deformation;

[0032] The fourth step is rough machining. The clamped and fixed substrate is rough machined by a wire cutting machine according to the set cutting path. The number of rough machining cuts is two. The first cut: leave a unilateral allowance of 0.5mm, and the second cut: leave a unilateral allowance of 0.3mm. Most of the allowance of the punch is removed, and cutting treatment is carried out;

[0033] The fifth step is tempering treatment. The cut substrate is held at 180°C for 2 hours to eliminate cutting stress and improve toughness;

[0034] Step 6: Secondary clamping. The substrate after tempering treatment is re-clamped and fixed by magnetic adsorption and glue. The substrate is adsorbed and positioned by a magnet fixture, and glue is applied to the edge where the substrate contacts the magnet fixture for auxiliary fixation.

[0035] Step 7: Semi-finishing. The re-clamped and fixed substrate is semi-finished processed by a wire cutting machine according to the set cutting path. The number of cutting times for semi-finishing is two. The first cutting: leave a margin of 0.25 mm on each side. The second cutting: leave a margin of 0.08 mm on each side, leaving a finishing allowance.

[0036] Step 8: Finishing. The semi-finished substrate is finish-cut by a wire cutting machine. The number of cutting times for finishing is three. The first cutting: leave a margin of 0.03 mm on each side. The second cutting: leave a margin of 0.02 mm on each side. The third cutting: no margin is left, and the substrate is processed into a punch that meets the final size and precision requirements.

[0037] Step 9: Deburring and cleaning. For the finished punch, remove the burrs and flash on the surface to ensure that the edge of the punch is smooth and does not affect use. Clean the punch with a cleaning liquid to remove impurities such as oil stains and chips on the surface, and then dry it with compressed air or put it in an oven to dry.

[0038] Step 10: Quality inspection. Detect the size of the punch by a coordinate measuring machine, with a diameter tolerance of ±0.005 mm and a perpendicularity of ≤0.002 mm / 100 mm. Detect the surface integrity of the punch by a scanning electron microscope, observe that the depth of the heat-affected layer is ≤20 μm and check for microcracks. Detect the hardness of the punch by a microhardness tester, with a surface hardness fluctuation of ≤±2 HRC.

[0039] Step 11: Packaging and warehousing. Package and warehouse the qualified punches.

[0040] It should be noted that the processing workshop in this embodiment maintains a constant temperature of 22 degrees Celsius, with a noise level less than 60 decibels, and collisions are strictly prohibited during the processing.

[0041] This processing technology eliminates cutting stress and improves toughness by performing a cutting-off treatment after rough machining and then tempering the cut-off substrate at 180°C for 2 hours. During the second clamping, magnetic adsorption and glue are used for clamping and fixing to reduce the stress deformation caused by the cutting-off of the punch. At the same time, the number of cutting times is increased to 7 times, so that the upper, middle, and lower size errors of the punch are ≤0.002 MM, and the surface finish is controlled between RA0.3 - RA0.35, effectively improving the precision and quality of the thick punch, thereby extending the service life of the stamping die, reducing the number of die repairs, lowering costs, improving the processing quality of products, reducing production costs, and meeting production requirements.

[0042] As described above, it is only the preferred embodiment of the present invention and is not intended to limit the present invention. Therefore, any modifications, equivalent replacements, improvements, etc. made to the above embodiments based on the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A processing technology for thick punches of molds for automotive precision parts, characterized in that, It includes the following steps: The first step is substrate pretreatment. The substrate to be processed is pre-heat treated to eliminate forging stress. The second step is to machine the wire threading hole. A wire threading hole is machined on the pre-treated substrate. The third step is clamping and fixing. The substrate after determining the wire threading hole is clamped and fixed. The fourth step is rough machining. The clamped and fixed substrate is rough machined by a wire cutting machine according to the set cutting path, removing most of the surplus of the punch and performing a cutting-off process. The fifth step is tempering treatment. The cut substrate is kept at 180°C for 2 hours to eliminate cutting stress and improve toughness. The sixth step is secondary clamping. The tempered substrate is re-clamped and fixed by magnetic attraction and glue. The seventh step is semi-finishing machining. The re-clamped and fixed substrate is semi-finished machined by a wire cutting machine according to the set cutting path, leaving a finishing allowance. The eighth step is finishing machining. The semi-finished machined substrate is finish machined by a wire cutting machine to process the substrate into a punch that meets the final size and precision requirements. The ninth step is deburring and cleaning. For the punch after finishing machining, the burrs and flash on the surface are removed to ensure that the edge of the punch is smooth and does not affect its use. The punch is cleaned with a cleaning solution to remove surface impurities, and then dried with compressed air or placed in an oven.

2. The processing technology of the thick punch for the die used in automotive precision parts according to claim 1, characterized in that: In the first step, the pre-heat treatment is stress relief annealing, kept at 650°C for 4 hours, cooled in the furnace to 200°C and then taken out of the furnace to eliminate forging stress.

3. The processing technology of the thick punch for the mold of automotive precision parts according to claim 1, characterized in that: In the second step, the wire threading hole is machined into shape using a φ3mm cemented carbide drill bit.

4. The processing technology of the thick punch for the mold of automotive precision parts according to claim 1, characterized in that: In the third step, an upper and lower double-layer clamping plate is used for clamping and fixing.

5. The processing technology of the thick punch for the mold of automotive precision parts according to claim 1, characterized in that: In the fourth step, the number of rough machining cuts is two. The first cut: leave a 0.5mm allowance on each side. The second cut: leave a 0.3mm allowance on each side.

6. The processing technology of the thick punch for the mold of automotive precision parts according to claim 1, characterized in that: In the sixth step, the substrate is adsorbed and positioned by a magnetic fixture, and glue is applied to the edge where the substrate contacts the magnetic fixture for auxiliary fixation.

7. The processing technology of the thick punch for the mold of automotive precision parts according to claim 1, characterized in that: In the seventh step, the number of semi-finishing machining cuts is two. The first cut: leave a 0.25mm allowance on each side. The second cut: leave a 0.08mm allowance on each side.

8. The processing technology of the thick punch for the mold of automotive precision parts according to claim 1, characterized in that: In the eighth step, the number of finish machining cuts is three. The first cut: leave a 0.03mm allowance on each side. The second cut: leave a 0.02mm allowance on each side. The third cut: no allowance.

9. The processing technology of the thick punch for the mold of automotive precision parts according to claim 1, characterized in that: After the ninth step, it also includes the tenth step of quality inspection, checking the size, surface integrity and hardness of the punch to see if they meet the requirements.

10. The processing technology of the die thick punch for automotive precision parts according to claim 9, characterized in that: After the tenth step of quality inspection and control, it also includes the eleventh step of packaging and warehousing. The qualified punches are packaged and warehoused.

Images