Complete production process of conventional self-tapping screws


The screw production equipment required for the entire […]

The screw production equipment required for the entire screw production process is roughly divided into: wire drawing machine, cold heading machine, tooth rubbing machine, etc. The following specifically describes the production process:

Screw production process-wire drawing

Wire drawing is also known as drawing line, drawing wire to cold heading machine. In general, there is another process before wire drawing is pickling. In order to remove the oxide film on the surface of the wire, the surface forms a layer of phosphate film, as far as possible to reduce the roughness of the wire and scratches on the mold. After pickling the wire rod, it is cold drawn by the wire drawing machine. Applicable to the length of wire required for large screws, nuts and self-tapping screws.

Screw production process-forming (nail blank)

For ordinary self-tapping screws, the first step is to form the head, generally after a die and two punching process. The head forming can be countersunk head, round head, large flat head, external hexagon, internal hexagon and so on.

Blocking: After moving the scissors in one direction, the wire stuck in the cutting die is cut into the required blank.

One punch: the die is fixed, and the first part of the die starts to form the product head, so that the next stroke can be completely formed. When the product is a slotted groove, a die is concave, and the elliptical groove product is a cross groove, a die is a concave square groove.

Second punching: After one punching, the punching tool works as a whole, the second punching die moves to the front of the punching die, and the second punching die works forward to shape the end of the product, after which the blank is pushed out of the drawing head by the rear punch.

Screw production process-rubbing teeth

Generally, the self-tapping screw embryo is made into a thread, which requires two dental plates, one fixed, and the other rolling semi-finished product moved, and the product is plastically deformed by kneading to form the required thread. In addition, if the nut is tapped by tapping-tapping.

Screw production process-heat treatment

Self-tapping screws are required for hardness, heat treatment (influencing factors) is necessary, so that the surface hardness and core hardness of the self-tapping screws can meet certain requirements before they can successfully drill holes without being too soft. Into.

Screw production process-surface treatment

Surface treatment is the process of forming a covering layer on the surface of the workpiece through a certain method. Its intention is to give the product a beautiful appearance and anti-corrosion effect. The appearance treatment methods are all attributed to the following methods: electroplating, hot-dip galvanizing , Mechanical plating, etc. Commonly used electroplating includes zinc plating, black/white nickel, blackening, phosphating, etc. For export products that have environmental quality requirements, the trivalent white zinc dephosphorization treatment is also called environmentally friendly white zinc.

Finally, after the first five processes are completed, the self-tapping screws will come out. Of course, it is necessary to conduct screening and drying of defective products. After that, the packaging and labeling will be delivered. Although the whole process is more than a dozen steps, it can be used as the standard screw (core product) for professional production of screws. It is important for every link to be checked, and every detail is not neglected.