The surface inspection of laptop screw is divided into two kinds. One inspection is before plating, and another one is after plating. That is to say, it is the inspection after the screw hardened and after surface treatment of screw. Before plating, we should inspect the dimension and tolerance of screw, and look whether it have reached national standards or customer requirements. After surface treatment of screw, we should inspect the plated screw. It mainly test the plating color and bad screws, etc. So that our laptop screw can be passed when the customers receive them. I will describe the inspection after screw treatment in detail below.
1.The appearance and quality requirements
Screw appearance inspection is inspected from the appearance, electroplated layer, etc.
2.The inspection of screw plating thickness
A. the method of measuring
The tools for measuring include micrometer, calipers, plug gauge, etc.
B. Magnetic method
The method is a non destructive measurement, using magnetic thickness gauge to measure the magnetic substrate non-magnetic coating layer.
C. microscopic method
It is also called the metallographic method. It is to put fasteners after etching on the metallographic microscope with a micrometer eyepiece amplification, measuring the section on the thickness of the coating.
D. Timing flow method
Timing flow method is used to dissolve the coating solution lingers on coating of local surface, according to the time required to the local plating solution, to calculate the thickness of the coating.
Those are all the inspection method of laptop screw. And there also are many other methods. If you want to know more about screws, you can contact us. We are a professional China screw manufacturer. We will try our best to help you!