Some common appearance defects of automobile stamping parts

2023-03-22 16:53:01

The appearance defects of the punching machine mainly include cracks, neck shrinkage, pits, corrosion, wrinkles, burrs, burrs, indentations, scratches, overlapping, etc. Some common appearance defects of automotive stamping parts are introduced below.

(1) neck shrinkage and cracking

The direct cause of shrinkage necks and cracks is that the stress exceeds the limit of the material during stretch forming, thereby forming shrinkage necks or cracks. Neck shrinkage and cracks generally occur in processes such as drawing, corner turning, and hole turning, which directly affect the life and structural strength of auto parts. Therefore, if severe neck shrinkage or cracks occur, the parts will be scrapped and the manufacturing cost will be reduced. A substantial increase. In addition, if neck shrinkage or cracks occur, outage line repairs typically take a long time, further increasing costs and reducing productivity.

(2) folds and overlaps

Wrinkling and overlapping are due to the large difference between the size of the thickness direction of the sheet and the size of the plane direction, resulting in instability in the thickness direction. After the stress in the plane direction reaches a certain level, the thickness direction is unstable, resulting in wrinkling. Wrinkling is further exacerbated, and overlapping occurs.

(3) Glitch

It is generally inevitable to have different degrees of burr defects in the blanking process of automobile stamping parts, but by improving the stamping process and improving the stamping conditions, burrs can be reduced. Occurrence will not only make the subsequent deformation process easy to crack due to stress concentration, but also bring difficulties to the delamination of the subsequent process blank. The big hair is easy to be scratched by the handle, and it is easy to drill out when welding, or the welding is not good. Therefore, the burr defects that have occurred are generally eliminated by rework of files, rolls, electrolysis, etc.

2. Automotive stamping parts - functional size defects

(1) There are few holes, the holes are deformed, and the holes are not drilled less. The reason is that the stamping leaks or the stamping is damaged, and it needs to be replaced.

If the new stamping and repositioning punch clearance is too large or the clearance is too large, hole deformation will occur and the punch clearance must be readjusted before production can continue. When the mold stroke is insufficient or the position is not suitable, the defect of not punching usually occurs. There are two main preventive measures. One is to adjust the slider to an appropriate height during debugging, and the other is to operate the equipment strictly according to the operating procedures.

(2) size does not match

In the manufacturing process of automobile stamping parts, due to improper operation of materials, molds, equipment, processes or employees, there are often differences between the size of parts and the size required for design and development. This kind of error is acceptable within a certain range. Different companies have different judgment standards for dimensional defect inspection according to the vehicle model and technical level.

3. Automotive Stamping Parts - Return Defects

(1) trim marks

When re-maintaining stamped individual parts, if the sandpaper is too coarse or the grinding force is too large, grooves and scratches may appear on the surface of the part. After the punch is painted, the grooves and scratches on the surface will be illuminated. Show melon face paint.

(2) The board is thin

During the reprocessing process of the punching machine, due to the long grinding time or high grinding force, it is often over-grinded, resulting in a plate thickness lower than the standard value, and the thinning of the plate will not only reduce the strength of the punching machine, but also affect the service life.

4. Inherent defects

In the early development process of automotive stamping parts, due to factors such as technology, work clothes, design and other factors, the defects that cannot be completely repaired in the process of stamping parts are called "inherent defects". For these defects, the common practice in the automotive stamping parts industry is curing and stabilize these inherent flaws.