Introduction
How are screws made as small parts commonly used in daily life? Screws are widely used in car bodies. Generally, they are made of metal or plastic, in a cylindrical shape, and concave convex grooves engraved on the surface are called threads. The main function of the screw is to connect two objects or fix the position of an object. Screws can usually be removed or re embedded at will without compromising their efficiency
Cold forming Vs machining
There are two ways to make a screw starts from metal steel: cold forming by header or machining.
Machining:
reaching the ideal shape by removing the material. Its advantages are high machining precision, no tooling limited. Its Disadvantages are high cost and low processing speed.
Cold forming by header:
Reaching the ideal shape by forming with the help of header force and a tooling (die and punch) fixed on the heading machine.
Its advantages are high speed low cost for mass production. Its Disadvantages is tooling limited for different parts.
Screw making process flows:
Screw cold forming
common screw:
large head screw:
Tread rolling
The cold heading blank is rolled out of the thread on thread rolling machine, and the screw thread is formed through the interaction between the movable thread flat dieand the fixed thread flat die .
Edited by:FMT|fastenermachinetool.com
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