According to our experience, we are happy to let you know the familiar stamping part defects during production processing along with analyzes the causes and provides preventive measures for reference.
1.1.Burrs: Burrs may be generated when the die blanking gap is too large, too small or uneven, the concave and convex die blades are not sharp enough, and the blanking state is not good.
Solution: Check the gap and the related part and repair the defect accordingly.
1.2. Uneven warping of parts:
a. During the blanking process, the parts have large tensile and bending forces and are prone to warping.
The improvement method is to use the punch and the press plate to press tightly during blanking and keep the sharp edge, which can achieve good results.
b. When the shape of the part is complex, the shear force around the part is uneven, so a force from the periphery to the center is generated, causing the part to warp.
The solution is to increase the pressing force.
c. When there is oil, air, etc. between the die and the part, or between the parts, the part will warp, especially thin materials and soft materials are more likely to warp.
Solution：The warping phenomenon can be eliminated by evenly applying oil and setting vent holes.
1.3. Wrinkling:
a. The drawing depth of the stamping part is too deep, resulting in too fast sheet material flow during the material feeding process, forming wrinkles.
b. The R angle of the die is too large during the drawing process of the stamping part, resulting in the inability of the punch to press the material during the drawing process, resulting in too fast sheet material flow and wrinkles.
c. The pressing ribs of the stamping part are unreasonable, the pressing ribs are too small and the position is incorrect, which cannot effectively prevent the sheet material from flowing too fast, forming wrinkles.
d. The mold positioning design is unreasonable, resulting in the inability to press the material during the drawing process of the stamping part or the pressing edge is too small, resulting in the inability to press the material during the drawing process, resulting in wrinkles.
The solution to wrinkling is to use a reasonable pressing device and a reasonable use of draw ribs.
1.4. Errors in dimensional accuracy:
a. The dimensional accuracy of the cutting edge in mold manufacturing does not meet the standard, resulting in excessive size of the part.
b. In stamping production, the part rebounds, causing the positioning surface of the next process to not fully match the part, causing deformation during the stamping process, affecting dimensional accuracy.
c. The part is poorly positioned, the design is unreasonable, and the part moves during stamping. There are also defects in the part design, resulting in inaccurate positioning, affecting dimensional accuracy.
d. Due to improper adjustment of the previous process or wear of the fillet, the multi-process parts are unevenly deformed, causing dimensional changes after punching.
Solution： For the above reasons that cause dimensional accuracy problems, we must take necessary control measures, such as reasonable stamping part shape and tolerance grade, improving mold manufacturing accuracy, and designing rebound compensation mechanisms.
1.5. Pressure injury:
a. There are debris on the surface of the material. Check whether there are debris on the surface of the material during stamping. If there are debris, clean it with an air gun and rags.
b. There are foreign objects on the surface of the mold. Use tools to clean foreign objects on the surface of the mold and select a suitable lower mold gap according to the thickness of the sheet.
c. The mold material is magnetic. Change the processing sequence, and process from the outside to the inside and line by line when punching the workpiece. Cut the edges (cut the edges) first and then punch the mesh. Special forming stamping may be deformed, which may be due to excessive pressure. The spring in the mold needs to be replaced.
d. The stamping oil does not meet the requirements. Replace the current stamping processing oil and choose a special stamping oil containing sulfide extreme pressure additives.
1.6. Scratches: The main reason for part scratches is sharp scars on the mold or metal dust falling into the mold. The preventive measure is to polish the marks on the mold and clean the metal dust.
1.7. Bottom cracks: The main reason for the bottom cracks of the parts is poor material plasticity or too tight pressing of the mold blanking ring. The preventive measure is to replace the material with good plasticity or loosen the blanking device.
1.8. Side wall wrinkling: The main reason for the side wall wrinkling of the part is that the material thickness is not enough (if it is relatively small, the thickness is allowed to be thinner) or eccentricity when the upper and lower molds are installed. The gap on one side is larger and the gap on the other side is smaller. The preventive measure is to replace the material immediately and readjust the mold.
1.9 Tool Wear:
Another common problem with metal stamping is tool wear. Over time, the tools used in the stamping process wear and become less effective, resulting in poor quality stamping. This can be due to a variety of factors, including improper maintenance, incorrect material selection, and overuse.
1.10 Material Selection:
Improper material selection is also a common problem with metal stamping. If the wrong or poor quality materials are used in a particular stamping job, it can lead to poor stamping quality, tool wear, and other problems.
