Briefly introduce: what is the processing technology of stamping die processing?
Brief introduction of stamping die processing technology
As the core equipment of precision manufacturing, the processing technology of stamping die directly determines the precision, life and quality stability of stamping parts. Stamping die processing is a systematic project that integrates mechanical processing, precision measurement, heat treatment and other fields. It needs to follow the core process of "design-blank preparation-precision processing-heat treatment-assembly and debugging", and realize high-precision molding of key parts such as die punch, die and guide mechanism through fine control of multiple processes. Starting from the core process, key processes and process characteristics, the processing technology of stamping die is described in detail below.
The first step of stamping die processing is die design and process planning, which is the basis to ensure the feasibility and accuracy of processing. In the design stage, the die structure design (including the layout of punch, die, die frame, guide mechanism, discharging device and other parts), dimensional tolerance marking (the tolerance of key dimensions is usually controlled within ±0.005mm) and process route planning should be completed in combination with the structural size, material characteristics and production batch of stamping parts. In the design process, CAD software should be used to establish a three-dimensional model, and the mold structure should be optimized through simulation analysis to avoid interference problems. At the same time, the machining accuracy requirements and material selection of each component are clearly defined (such as high-strength die steels such as SKD11 and DC53 are commonly used for convex and concave dies, and 45 # steel or cast iron is used for the die frame), which provides accurate basis for subsequent processing.
The next step is the blank preparation process, which aims to provide the basic blank that meets the requirements for precision machining. According to the structural size and performance requirements of die parts, the blank preparation methods mainly include forging, casting and plate cutting: for key working parts such as punch and die, forging process is needed to process the blank, and the internal structure of the material is improved by high-temperature forging to improve the strength, hardness and wear resistance of the material, so as to ensure that the die is not easy to wear or crack in the long-term stamping process; Casting blanks can be used for structural parts such as die sets to reduce production costs; Small and simple parts can be directly cut into blanks by plate cutting (such as plasma cutting and laser cutting). After the blank is prepared, it needs to be annealed to eliminate the internal stress generated during forging or casting, reduce the hardness of the material, and create good conditions for subsequent machining.
Precision machining is the core link of stamping die processing, and the high-precision forming of parts needs to be realized step by step through multiple processes. First, rough machining is carried out, using milling machines, lathes and other equipment to remove the excess materials on the surface of the blank, initially forming the approximate shape and size of the parts, and reserving a machining allowance of 3-5mm for finishing. The rough machining should pay attention to efficiency and control the machining error at the same time to avoid the difficulty of subsequent finishing. Then enter the semi-finishing stage, and further refine the component structure through CNC milling machines, grinders and other equipment to improve the dimensional accuracy and surface roughness. After semi-finishing, the dimensional tolerance of the component needs to be controlled within ±0.1mm, and the surface roughness reaches Ra 1.6 ~ Ra 3.2 μ m..
Finishing is the key process that determines the precision of the die, and high-precision machining equipment and technology are needed: for the key parts such as the cutting edge of the punch and the die, EDM or WEDM are used to realize high-precision molding by electric erosion, and the precision of wire cutting can reach ±0.002mm, which can accurately process complex special-shaped structures and tiny dimensions; For the plane, guide hole and other parts of the mold, surface grinder and internal grinder are used for grinding to ensure that the shape and position tolerances such as flatness and verticality meet the requirements, and the surface roughness after grinding can reach Ra 0.4 ~ Ra 0.8 μ m. Some high-precision molds need polishing. By mechanical polishing and chemical polishing, the working surface of the mold is smooth and burr-free, which reduces the adhesion and wear of materials during stamping and prolongs the life of the mold.
Heat treatment process is an important link to improve the performance of die. By controlling the processes of heating, heat preservation and cooling, the microstructure of die material is changed, and its hardness, wear resistance and toughness are improved. The heat treatment process needs to make a targeted plan according to the characteristics of die materials: for die steels such as SKD11, quenching and tempering are usually adopted, the quenching temperature is controlled at 950~1050℃, and the material is cooled quickly after heat preservation, so that the martensite structure can be obtained and the hardness can be improved (HRC reaches 60 ~ 62); Tempering temperature is 200~250℃, which can eliminate quenching internal stress, improve the toughness of materials and avoid brittle fracture of dies during use. After heat treatment, the die parts should be aged to further stabilize the size and prevent deformation in the subsequent use.
Finally, the assembly and debugging of the mold, assembling the processed parts into a complete mold according to the design requirements, and debugging the mold. During the assembly process, it is necessary to ensure the matching accuracy of all parts, especially the coaxiality and clearance of the guiding mechanism (such as guide post and guide sleeve) to ensure the smooth movement of the mold; The gap between the punch and the die should be evenly distributed and meet the requirements of stamping process (usually 5%~12% of the material thickness). After the assembly is completed, the die is tested, and the forming effect, dimensional accuracy of parts, surface quality and stability of the die are checked by stamping test pieces. If problems such as excessive burrs, out-of-tolerance dimensions and stuck die are found, the die needs to be disassembled and adjusted, such as grinding the cutting edge, adjusting the gap, repairing the guide mechanism, etc., until the die test is qualified, the die can be put into mass production.
In addition, strict quality inspection should be carried out in the process of stamping die processing. From blank processing to finished product assembly, high-precision inspection equipment such as three-coordinate measuring instrument, projector and micrometer should be used in each process to detect the size and shape tolerance, find out the processing error in time and adjust the process parameters to ensure that the overall accuracy of the die meets the design requirements. At the same time, attention should be paid to equipment maintenance, tool selection and cutting parameter optimization in the machining process to reduce machining errors and improve production efficiency.
To sum up, the stamping die processing technology is a complex process of multi-process coordination and high-precision control, and each link directly affects the final performance of the die. With the development of precision manufacturing technology, CNC machining, EDM, laser machining and other advanced technologies are widely used in die processing, which promotes the development of stamping die in the direction of higher precision, longer life and higher efficiency, and provides strong support for precision stamping production in electronic products, auto parts and other industries.
