Measures and approaches to improve the service life of cold stamping molds
Reasonable design structure of cold stamping molds, suitable mold material selection, and mold processing and assembly debugging process are the basis for improving the service life of cold stamping molds. Therefore, automotive hardware stamping parts; When designing molds, various factors that affect the service life of the mold should be comprehensively considered, and then a more economical and high-quality cold stamping mold should be designed and manufactured.
1. Optimize the structural design of cold stamping molds
A reasonable design structure for cold stamping molds is a prerequisite for the service life of the molds. The service life of cold stamping molds is closely related to reasonable structural design. At the beginning of the design, in addition to other design requirements for cold stamping molds, the toughness, rigidity, and strength of the molds are required to prevent deformation, damage, or increased wear of the convex, concave, and other structural components during the punching process. Mold design should adopt guided mold design as much as possible, while also considering mold design clearance. If the design clearance is too small or too large, it will increase the wear of convex and concave molds, leading to mold damage and reduced service life. In addition, taking into account the fastening and positioning methods of the mold, strengthening the fastening degree and reasonable contact area of the mold components, and improving the overall manufacturing accuracy and quality of the mold, especially the design with reinforcing ribs, reinforcing plates, etc., will enhance the overall toughness, rigidity, and strength of the mold.
2. Reasonably design the clearance between the convex and concave molds of the cold stamping die
The size of the punching gap in a cold stamping die directly affects the quality of the stamped part, the service life of the cold stamping die, and the magnitude of the punching force. The gap value selected for mold design should be able to reduce the punching force and unloading force. Mature experience should be used to design reference values in the manual. At the same time, according to the specific situation, the gap between the convex and concave molds should be appropriately enlarged within the allowable range of product quality. This will greatly reduce the wear of the convex and concave molds. When the gap between the convex and concave molds is too small, it will increase the degree of friction and wear of the mold. Therefore, correctly mastering the design of the clearance between the convex and concave molds can double the service life of the mold.
3 Correct Selection of Cold Stamping Mold Materials
To improve the quality of metal stamping parts; The correct selection of mold materials is crucial for the service life. In practice, the material of the mold can be determined based on the batch size (number of pieces) of the products being punched. When the batch production is large, the material used should be a mold material with good toughness, high rigidity, and high properties. When the batch output is low, general mold materials can be selected. The selection of mold materials can also be determined based on the material properties of the stamped material and the quality requirements of the stamped parts. When the dimensional tolerance of the stamped parts of the mold is high, the gap between the mold is small, and the friction between the convex and concave molds of the mold and the stamped parts is large, materials with high selectivity and sufficient toughness can be selected. At the same time, the different strengths and toughness of the punching materials, as well as the specific situation of the punching equipment, should also be considered. The commonly used materials for convex and concave molds include CrWMn, CrIZMoV, Cr12, Cr12Mov, and carbon tool steel.
4 Reasonable Cold Stamping Mold Heat Treatment Processes
To improve the service life of cold stamping molds, it is a key and important step to carry out reasonable heat treatment processes for materials with different materials and properties. During the quenching process, if the heating temperature is too high, it will cause the convex and concave molds to be quenched, resulting in excessive brittleness and easy breakage and fragmentation. If the quenching hardness is too high or the quenching layer is too deep, it is also easy to deform and crack during cooling, or hidden cracks are difficult to detect, reducing the service life of the mold. During the quenching process, if the heating temperature is not sufficient, the hardness of the quenching process may not meet the technical requirements, and the convex and concave molds are prone to deformation under stress, which reduces the service life of the molds. So when manufacturing cold stamping molds, it is important to have a reasonable, correct, and proficient grasp of the heat treatment process technology.
Processing and assembly quality of 5 cold stamping molds
In the process of cold stamping mold processing and assembly, the machining accuracy and quality of the mold, different machining accuracy and quality, have a great impact on the service life of the mold. The higher the precision and quality of cold stamping die processing, the longer its service life, and conversely, it will shorten its service life. Generally, standard mold frames are commonly used for cold stamping molds, as they are produced in a standardized manner, their guiding quality is not a problem. If it is a self-made mold frame, during the assembly process, the accuracy of the guide column and guide sleeve should be ensured, and the sliding clearance of the guide column and guide sleeve should be reasonable. When assembling convex and concave molds, the gap adjustment should be uniform, and the surface smoothness of the convex and concave molds should meet the design requirements. The parallelism and perpendicularity of each component should be ensured, especially the perpendicularity between the convex mold and the fixed plate. The perpendicularity between the concave mold and the surface should be within the allowable tolerance range, and the connecting bolts and pins of each component should be firmly connected.
6. Use and maintenance of cold stamping molds
When using cold stamping molds, appropriate and high-precision stamping equipment should be selected correctly, as well as suitable punching force. The punching force should generally be greater than 30% -40% of the weight of the part. When installing the mold, it is necessary to strictly control the insertion of the convex mold into the concave mold to reduce wear. If the insertion is too deep, it will increase friction. The fixed mold should be firm. To reduce wear, suitable lubricants can be applied to the stamped sheet (part), convex and concave molds to reduce the degree of mold wear and friction. When it is found that the edges of the convex and concave molds are not sharp enough, the edges of the convex and concave molds should be sharpened in a timely manner to make them sharp. During the period when the mold is not in use, it should be properly sealed and protected. Molds with compression devices should be stored in a free state. There should be some gap between the convex and concave molds to protect the cutting edges of the convex and concave molds from damage, and the surface should be coated with oil for rust prevention. The working surface of the mold should be kept clean regularly to prevent debris or dust from falling on it.
With the development of industry, various industries have put forward requirements for the processing quality of automotive stamping parts, especially the service life of cold stamping molds. To improve the service life of cold stamping molds, we need to constantly explore, research, summarize, and optimize the design structure of molds, select mold materials, improve the processing technology and assembly debugging technology of cold stamping molds, especially in the design, material selection, and processing of convex and concave molds. Only in this way can we continuously improve the service life of cold stamping molds.
