What matters should be paid attention to in the processing of automobile stamping die parts?

There are many matters needing attention in the processing of automobile stamping die parts. The following are introduced in detail from the aspects of processing accuracy, material selection and processing technology:

machining precision

Dimensional accuracy: the dimensional accuracy of automobile stamping die parts directly affects the assembly accuracy of the die and the quality of stamping parts. For example, the dimensional tolerance of key parts such as punch and die is usually controlled within ±0.01mm to ensure the dimensional accuracy and stability of stamping parts.

Form and position tolerance: The form and position tolerance of parts is also very important. For example, the shape and position tolerances such as cylindricity and verticality are required to be within a high precision range for the guiding parts of the die (such as guide posts and guide sleeves), and generally the cylindricity should be controlled within 0.005mm, so as to ensure the guiding accuracy of the die in the stamping process and avoid problems such as eccentric load and die gnawing.

Material selection

Performance matching: according to the use requirements and working conditions of the mold, choose the appropriate mold material. For stamping dies bearing large impact load, such as automobile panel dies, alloy steel with high strength and toughness, such as Cr12MoV, is usually selected to ensure that the dies will not be broken, deformed and other failure forms during long-term use.

Material quality: ensure the quality of the selected materials, and check whether the hardness of the materials meets the requirements and whether the structure is uniform. High-quality materials are the basis to ensure the processing quality and service life of die parts. For example, if the hardness of the material is uneven, problems such as uneven tool wear and poor surface quality will easily occur during machining, which will also affect the wear resistance and corrosion resistance of the die.

processing technic

Reasonable arrangement of working procedures: make a reasonable processing route, follow the principle of rough machining first, then finish machining, and gradually improve the machining accuracy and surface quality of parts. For example, when machining a mold cavity with a complex shape, rough milling is used to remove most of the surplus, and then semi-finish machining and finish machining are carried out to reduce machining stress and deformation and ensure the dimensional accuracy and surface roughness of the cavity.

Control of machining parameters: according to the material performance and machining requirements, reasonably select cutting parameters, such as cutting speed, feed rate and cutting depth. For die steel with high hardness, the cutting speed should not be too high, otherwise it will easily lead to increased tool wear or even edge collapse; Feed and cutting depth should also be properly controlled to ensure the surface quality and dimensional accuracy. For example, when processing die steel of HRC50-55, the cutting speed is generally controlled at 50-80m/min and the feed rate is between 0.05-0.1mm/r..

Heat treatment process: heat treatment is an important link to improve the performance of die parts. In the process of machining, the heat treatment process should be arranged reasonably according to the types of materials and the requirements of mold use. For example, for some high alloy steel dies, quenching and tempering after rough machining can improve the hardness, strength and wear resistance of the materials; Nitriding after finishing can further improve the hardness and wear resistance of the die surface, and at the same time improve the corrosion resistance and demoulding performance of the die.

surface quality

Machining surface roughness: the surface roughness of automobile stamping die parts directly affects the surface quality of stamping parts and the demoulding performance of the die. For example, the surface roughness of die cavity is generally required to reach Ra0.8-1.6μm, so as to ensure that the surface of stamping parts is smooth and free from defects such as strain and scratch, and it is also conducive to the smooth demoulding of stamping parts in the die.

Surface treatment: In order to improve the surface hardness, wear resistance and corrosion resistance of die parts, surface treatment is usually needed. Common surface treatment methods include hard chromium plating, nitriding and PVD coating. For example, hard chromium plating can improve the hardness and smoothness of the die surface, reduce the friction coefficient, facilitate the demoulding of stamping parts, improve the wear resistance and corrosion resistance of the die, and prolong the service life of the die.

Inspection and quality control

Process inspection: in the process of machining, it is necessary to strengthen the inspection of parts and components to find and correct machining errors in time. For example, after each working procedure is completed, the size, form and position tolerance and surface quality of the parts should be tested, and the precision measuring equipment such as three-coordinate measuring instrument and profilometer should be used to ensure the machining accuracy of the parts meets the requirements.

Finished product inspection: After machining is completed, complete finished product inspection shall be conducted on the die parts, including appearance inspection, dimensional accuracy inspection, shape and position tolerance inspection, hardness inspection, etc. At the same time, it is necessary to carry out flaw detection on the parts, such as ultrasonic flaw detection and magnetic particle flaw detection, to detect whether there are cracks and other defects in the parts, so as to ensure the reliable quality of the mold parts.

Assembly and debugging

Cleaning of parts: Before assembly, thoroughly clean the parts of the mold, remove impurities such as oil stain and iron filings remaining during processing, and ensure the surface of the parts to be clean. After cleaning, antirust agent can be used for protection to prevent parts from rusting.

Assembly accuracy control: strictly control the assembly accuracy of the mold according to the assembly process requirements. For example, the gap uniformity of the die should be controlled within a certain range, and the gap tolerance of the general blanking die should be controlled within ±0.05mm to ensure the quality of stamping parts and the service life of the die. At the same time, it is necessary to ensure that all parts of the die are firmly installed and reliably connected to avoid problems such as looseness and displacement during stamping.

Debugging optimization: after the assembly is completed, debug the mold. Through die trial, check whether the stamping process of the die is reasonable and whether the quality of stamping parts meets the requirements. According to the test results, the necessary adjustment and optimization are made to the die, such as adjusting the die gap and correcting the stamping process parameters, until the die can stably produce qualified stamping parts.