The appearance, outer diameter and hardness of raw materials and production equipment shall be inspected by micrometer, vernier caliper, Rockwell hardness tester and other instruments before the products are put into production, so as to prevent unqualified raw materials from appearing on the production line and reduce unqualified products from the source.
Inspect the appearance, head diameter and length of products in cold heading and wire rolling stage through vernier caliper, micrometer and other instruments to ensure that the size of each part of the product is within the standard range and reduce the flow of nonconforming products into the next stage of production.
The corrosion resistance, outer diameter and thread performance of electroplated products are tested by salt spray tester, micrometer and general gauge, so as to ensure that the product performance meets the standard and can adapt to worse environment at the same time.
