1. Adhesion and scratches: due to the friction between the material and the punch or die, the defects appear on the surface of the workpiece or mold
2. Burr: It mainly occurs in the shearing die and blanking die, and the gap between the cutting edges will produce burrs if the gap is large or small;
3. Line offset: When the part is formed, the part that is in contact with the mold is squeezed and a line is formed;
4. Concavo-convex: There are foreign objects (iron scraps, rubber, dust) mixed in the uncoiling line to cause convexo-concave;
5. Zigzag: Zigzag or strain occurs in the r-angle part or embossed part of the workpiece due to uneven stress, poor drawing bead matching, or poor control of the press slider.
6. Wrinkles: Wrinkles on the edges or r parts are caused by poor adjustment of the press slider, low precision of the press, improper adjustment of the air cushion pressure, large punch or r part, etc.
7. Other specific problems: In daily production, you will encounter situations where the punching size is too large or too small (it may exceed the specifications) and the size of the punch is large, except for the design size of the forming convex and concave molds In addition to factors such as processing accuracy and blanking gap, the following aspects should also be considered.
8. Method for restraining stamping parts from turning and twisting
⑴. Reasonable mold design. In the progressive die, the arrangement of the blanking sequence may affect the accuracy of stamping part forming. For the blanking of small parts of stamping parts, generally arrange a large area of blanking and blanking, and then arrange a small area of blanking and blanking to reduce the impact of punching force on the forming of stamping parts.
⑵. Squeeze the material. Overcoming the traditional mold design structure, a material gap is opened on the discharge plate (that is, when the mold is closed, and the material can be compressed. The key forming part, the discharge plate must be made into a block structure to facilitate the solution of long Time stamping results in wear (pressing) damage in the press part of the discharge plate, which cannot press the material.
⑶. Add strong pressure function. That is to increase the size of the pressing part of the unloading insert (the normal unloading insert thickness H + 0.03mm) to increase the pressure on the die side material, thereby suppressing the stamping parts from turning and twisting during punching.
⑷. The edge of the edge of the punch is repaired with a slope or arc. This is an effective way to reduce buffer cutting power. By reducing the buffer cutting force, the tensile force on the material on the side of the die can be reduced, so as to achieve the effect of suppressing the turning and twisting of the stamping parts.
⑸. In daily mold production, care should be taken to maintain the sharpness of punching convex and concave die edges. When the cutting edge wears, the tensile stress on the material will increase, so the tendency of the stamping part to turn over and twist will increase.
⑹. Unreasonable blanking gap or uneven gap is also the cause of stamping parts turning and twisting, which needs to be overcome.
