There are two types of special screw threads. First, the cutting process: the second is extrusion processing.
The cutting process is usually lathe processing, the round bar of the material you need, the diameter of the round bar is the maximum outer diameter of the special screw. The tooth type is processed by the cutter, and the front end of the turning tool should be shaped like the size of the screw shape. Otherwise, the assembly will have an influence. Then the lathe is machined to machine the thread. The common point is to hollow out the excess material of the round rod into a thread by a turning tool. This kind of processing method is suitable for small batch and high precision processing. However, the processing cost is high and the efficiency is low. The cost of general lathe processing is 1-2 times higher than that produced by cold heading machines.
Extrusion processing is processed by professional screw equipment. Our screw manufacturers call it a boring machine. The use of cold-twisted screw fasteners is not the use of iron rods, but the use of screw wire, the diameter of the screw wire is the middle of the maximum size of the screw tip and the minimum size of the bottom end of the screw. The flow properties of the metal material are rapidly extruded by the mold, and the extrusion processing can realize mass production in a batch, and the quality is stable. Low cost and high efficiency for large-volume, large-scale production.
