Eight points reveal the specific cause of the mold burst(2)

3. The flatness of the mold grinding is not enough, which causes deflection.
    The quality of the surface of the mold working parts has a very close relationship with the wear resistance, fracture resistance and adhesion resistance of the mold, which directly affects the service life of the mold. In particular, the surface roughness value has a great impact on the life of the mold. If the surface roughness value is too large, stress concentration will occur during work, and cracks will easily occur between its peaks and valleys, which will affect the durability of the die and affect the durability of the die. The corrosion resistance of the workpiece surface directly affects the service life and accuracy of the die. For this reason, the following matters should be noted:
    During the processing of mold working parts, it is necessary to prevent the surface phenomenon of grinding burned parts, and the grinding process conditions and methods should be strictly controlled (such as parameters of grinding wheel hardness, particle size, coolant, feed amount, etc.)
    During the machining process, macro-defects such as knife marks, interlayers, cracks, and impact scars should be prevented on the surface of the mold working parts. The existence of these defects will cause stress concentration, become the source of fracture, and cause early failure of the mold.
    The use of grinding, grinding and polishing and other fine processing and fine processing, to obtain a smaller surface roughness value and improve the service life of the mold.
    4. Design process: Insufficient mold strength, too close knife edge spacing, irrational mold structure, insufficient number of template blocks, no padding feet, inaccurate mold orientation, and unreasonable gaps.
    1) Layout and edging. Unreasonable reciprocating feeding and layout methods and too small overlap values ​​will often cause sharp wear of the mold or convex and concave mold damage. Therefore, while considering the improvement of the material utilization rate, it is necessary to reasonably select the layout method and the overlap value according to the processing batch, quality requirements of the parts and the mold clearance, so as to improve the life of the mold.
    2) Precision of the guide mechanism of the mold. Accurate and reliable guidance has a great effect on reducing the wear of the mold's working parts and avoiding damage to the convex and concave molds, especially the gapless and small gap punching dies, composite dies and multi-stage progressive dies are more effective. In order to improve the life of the mold, it is necessary to correctly select the guidance form and determine the accuracy of the guidance mechanism according to the requirements of the process nature and part accuracy. In general, the accuracy of the guiding mechanism should be higher than the mating degree of the convex and concave molds.
    3) The geometrical parameters of the cutting edge of the mold (convex, concave). The shape, fit clearance and fillet radius of the convex and concave dies not only greatly affect the forming of the stamping part, but also have a great influence on the wear and life of the die. For example, the fit clearance of the mold directly affects the quality of the blanking part and the life of the mold. For higher accuracy requirements, a smaller gap value should be selected; otherwise, the gap can be appropriately increased to improve the mold life.