[Analysis of quality objection to abnormal sand patterns]
The customer purchased a batch of stainless steel dry mill NO.4/240# sheets. After pulling them back, they found that the plate surface was abnormal and could not be used normally, so they raised a quality objection.
It is understood that the batch of stainless steel material is 304, thickness 1.5mm, size 1219×2438mm standard board, a total of 6 boxes of about 360 sheets.
The customer complained that the surface sand patterns of No.4/240# of this batch of steel plates were inconsistent, most of which were normal, but there was a box of steel plates with relatively thick patterns, similar to No.4/120#, but with relatively shallow patterns.
According to the label on the wooden box, it can be seen that the steel plate with the normal grain is processed first, while the steel plate with the abnormal grain is processed later. This kind of phenomenon is caused by excessive abrasive belt wear.
Dry grinding NO.4 generally uses abrasive belts. A large number of fine abrasive particles, such as silicon carbide, alumina, etc., are attached to the surface of the abrasive belt. After a long period of friction, these particles are smoothed, resulting in a gradual change in the grinding pattern. Coarse to shallow.
Generally speaking, the grinding life of the abrasive belt is about 300 steel plates, but this number will vary greatly with the different grinding parameters, so it mainly depends on the observation and judgment of the operator.
However, because the abrasive belt wear is a gradual process, it is not easy to check the sand pattern changes, and the thickness of the sand pattern itself does not have a very intuitive judgment standard, so subtle differences in the sand pattern are inevitable.
After negotiation, the customer agreed to continue to use the batch of steel plates, and the processor also made a commitment to strictly inspect the strength, stabilize the processing quality, and meet customer needs.