How to detect the surface of self-tapping screw

Self-tapping screws are also very common in our life, mostly used for the connection between thin metal plates (steel plate, saw plate, etc.). So how to detect the surface of self-tapping screw?

1. One is the detection of self-tapping screws before electroplating after production. We check the dimensions and tolerances of self-tapping screws to see if they meet the customer's requirements. Mainly a measuring method: the amount of micrometer, vernier caliper, plug gauge and so on.

2. The other is the inspection of self-tapping screws after electroplating, mainly testing the color of electroplating and whether there are bad screws. So that when we deliver to the customer, the customer will be satisfied after receiving the goods. Self-tapping screw surface after the inspection including: self-tapping screw appearance, electroplating and other aspects of the inspection.

⑴ Magnetic method

The magnetic method is used to measure the thickness of the coating layer, which is the non-destructive measurement of the non-magnetic coating layer with the magnetic thickness meter.

⑵ microscopic method

Microscope method, also known as metallographic method, is to place the corroded fasteners on a metallographic microscope with microscope to magnify and measure the thickness of the coating on the cross section.

(3) Timing liquid flow method

Timing liquid flow method, is to use the solution to dissolve the coating on the local surface of the coating, according to the local coating dissolved in time, to calculate the thickness of the coating, and coating drip method.

The above points are several methods of self-tapping screw surface detection, I hope to help you.