1. Burr: Burr may occur if the die blanking gap is too large, too small or uneven, concave, punch blade is not sharp enough, and the blanking state is not good.

2. The parts are warped and uneven:
a. In the process of blanking, the tensile and bending forces of the parts are large, and warping is easy to occur. The improved method can be used to press the punch and the pressing plate tightly and keep the sharp cutting edge when blanking, and good results can be received.
B. when the shape of the part is complex, the shearing force around the part is not uniform, thus generating a force from the surrounding to the center, causing the part to warp. The solution is to increase the pressure force.
C when there is oil, air, etc. between the die and the part, the part and the part, the part will warp, especially thin material and soft material. Can be evenly oiled, set the vent to eliminate the warping phenomenon.

3. Wrinkling:
A. Stamping parts drawing depth is too deep, resulting in parts in the process of feeding sheet material flow too fast, the formation of wrinkles.
B. stamping parts in the stretching process of the concave die R angle is too large, resulting in the stamping process can not press the material, resulting in the sheet metal flow too fast to form a wrinkle.
C. stamping parts pressing rib is unreasonable, pressing rib is too small and the position is not correct, can not effectively prevent the sheet metal flow too fast, the formation of wrinkles.
D. mold positioning design is unreasonable, resulting in stamping parts stretching process can not press the material or pressing material edge is too small, resulting in the stretching process can not press the material, resulting in wrinkling. The solution to wrinkling is to use a reasonable pressing device and a reasonable use of drawbead.

4. Dimensional accuracy error:
A. the dimensional accuracy of the cutting edge in mold manufacturing is not up to standard, resulting in the size of the parts.
B. in the stamping production, the part springback, resulting in the next process positioning surface and the part is not completely consistent, deformation occurs in the stamping process, affecting the dimensional accuracy.
C. parts positioning is poor, the design is unreasonable, stamping parts produce movement. There are also defects in the design of the parts, resulting in inaccurate positioning and affecting dimensional accuracy.
D. due to improper adjustment of the previous process or wear of rounded corners, the multi-process parts are unevenly mentioned during deformation, resulting in dimensional changes after punching. For the reasons of the above-mentioned dimensional accuracy problems, we should take necessary control measures, such as reasonable stamping parts shape and tolerance level, improve the precision of mold manufacturing, design springback compensation mechanism and so on.

5. Pressure injury:
a. There are sundries on the surface of the material. Check whether there are sundries on the surface of the material during stamping. If there are sundries, clean them with air gun and rags.
B. foreign matter on the surface of the mold. Use tools to clean the foreign matter on the surface of the mold, and select the appropriate lower mold gap according to the thickness of the plate.
C. mold with magnetic material. Change the processing sequence, punch the workpiece from outside to inside processing, line by line processing. First cut the edge (cut the edge) and then punch the mesh. The special forming stamping is deformed, which may be due to excessive pressure. The spring in the mold needs to be replaced.
D. stamping oil does not meet the requirements. Replace the current stamping processing oil, select special stamping oil containing vulcanized extreme pressure additive.

6. Scratch: The main reason for the part scratch is that there are sharp scars on the mold or metal dust falls into the mold. Preventive measures are sanding the marks on the mold and cleaning up the metal dust.

7. Bottom crack: The main reason for the crack at the bottom of the part is the poor plasticity of the material or the pressure of the mold blank holder is too tight. Precautions are to replace material with good plasticity or to loosen the edge holder.

8. Side wall wrinkling: The main reason for the side wall wrinkling of the part is that the material thickness is not enough when the upper and lower molds are installed (if it is relatively small, the thickness is allowed to become thinner) or eccentric. This results in a larger gap on one side and a smaller gap on the other side. The precaution is to change the material immediately and readjust the mould.