[Highlights on the Side of Slitting Roll] Quality Objection Analysis
Case Overview
The customer purchased a batch of slit rolls for production, but after the purchase came back, they found that there were bright spots on the side of this batch of slit rolls, which were very obvious and affected the customer’s subsequent processing, so the customer complained to the purchaser and applied for a quality objection.
Case Study
The supplier attaches great importance to the problems reported by the customer and immediately arranges a technician to check them at the customer’s site.
We know that when the stainless steel coil is normally slit, the side of each steel strip can be seen as obvious layering. From top to bottom, about 1/3 is bright and 2/3 is dark. This happens because in slitting, the upper 1/3 is cut from a disc, and the surface is smooth, so it is shiny; the lower 2/3 is a torn layer with a rough surface, so it is dark.
After an on-site inspection, I learned about the customer’s complaint. The bright spot shows that the shearing at this place is problematic, which causes the shearing layer at this place to increase, and the bright belt becomes larger. The sideshows little bright spots.
The most likely reason for the appearance of bright spots in the disc cutter. Generally speaking, it may be caused by foreign matter sticking to the disc cutter. Under the same reduction amount, the shear layer is enlarged when the foreign matter is stuck, so bright spots appear. Therefore, the light spot has periodicity, which is the circumference of the disc.
The presence of foreign matter may be that the disc cutter was not cleaned before processing, or it may be dust or metal scraps during cutting. The end surface roughness and burrs at the bright spots may be abnormal. For some precision machining industries, these defects are not allowed.
Case Suggestion
In processing management, the disc cutter maintenance procedures need to be strictly implemented. The disc cutter must be cleaned and wiped before and after use, and shall not be placed in the open air. The striped coil purchased by the customer shall be scrapped.