Screws are normally made from wire which is supplied in large coils
and forming by the heading machine and threading machine.
After forming, the screws are carbonized to increase the mechanical strength.
Then, in order to prevent corrosion and improve the appearance, the screws are
being coated with surface treatment. Such as phosphate coating, electroplating with
zinc plated, dacromat, or ruspert is applied for customer need.

Screw Production Flow Chart

Head Forming

Thread Rolling

Heat Treatment

Surface treatment