Self drilling screw production is a complex process with strict technical requirements.The production process is as follows:
First step:Raw material selection
The diameter of the wire is generally 5-19mm, and the diameter of the wire required when selecting the material is larger than the diameter of the corresponding product.
Second step:Wire handling
①Rough pluck
Remove the oxidized skin produced on the surface of wire during production and storage.
②Anneal
Heat the wire to different temperature intervals for a corresponding time, and then cool it naturally in the air. Reduce the hardness of wires and eliminate stress to facilitate post-processing.
③Wash with acid
Add a layer of oxide film to the wire to make it easier to process and mould, while reducing the loss of abrasives.
④Meticulous pluck
According to different product requirements, the wire is pulled to the corresponding wire diameter coarseness.
⑤Test
Check whether the roughness meets the standard.
Third step:Moulding process
①Cold-forming
The cold-forming machines cut the wire to the required length and emits nuts and marks at the same time.
②Pinch pointing
Create a swallowtail shape that can penetrate steel plates.Strictly control concentricity,blade width and other parameters.
③Thread-rolling
Rub the thread on the surface of the screw.
Fourth step:Heat treatment process
①Wash surface
Wash off the grease on the screw surface.
②High-temperature carburizing
Let carbon atoms penetrate into the surface layer of the screw and increase the surface hardness of the screw.
③Quenching
High-temperature carburizing and quenching work together to form a layer of crystal on the surface of the screw,so that the surface hardness meets the requirements.
④Secondary cleaning
Remove the quenching oil form the screw surface.
⑤Low temperature tempering
Reduce the hardness of the screw core to make the screws tough,so that the screws are not easy to break.
Fifth step:Test
Detect the surface hardness,core hardness,torque value,attack speed of the product to ensure that all parameters meet the standard.
Sixth step:Surface treatment
①Wash with acid
Thoroughly clean the surface of screws.
②Electroplate
Use electrolysis to attach a layer of metal film to the surface of the self drilling screw to prevent screws from rusting and prolong the use time.
Seventh step:Add washer
Add washers to screws to prevent water seepage during use.
Eighth step:Packing
Packed according to the model,and put it into a full serve ball in the warehouse.
