What Are the Defects in the Manufacture of Fasteners?

High-strength non-standard screws in each production step have to be paid attentions, the process of cold heading is taken for an example, under normal circumstances, high-strength bolt or nut head, such like the flat head semi-hex body rivet nut, is formed through cold heading process, only in the case of producing more complex head types, it is necessary to use cutting methods. In general, the problems that will occur through the whole process include:

1. Screw fasteners are eccentric, this error is usually made in the stamping process, or due to the adjustment error of the machine.

2. Tilted head, this problem often occurs. A mistake is made when in the adjustment of machine, or caused by errors in the first stamping process.

3. The head of bolt mould is not round, the main reason is that the grinding tool has a problem, grinding material quality is not good, after the production of some screws, the grinding tool is much worn, so the fastener head cannot be round.

4. Cracks or bilayers, it's mostly caused by the improper operations in the molding process.