When testing the thickness of copper plating layers using an electrolytic plating thickness gauge and metallographic microscopic thickness measurement respectively, there are significant differences. The reasons are roughly as follows:

1. 1. Plastic Substrates

2. In the case of plastic substrates, if the metallographic preparation is poor, copper curling will occur, resulting in a significantly larger thickness (Figure 1).

3. 2. Electrolytic Test Completeness

4. During the electrolytic test, the copper plating layer must be tested completely, and there should be no obvious island - like incomplete test points, otherwise the copper thickness will be too thin (Figure 2).

5. 3.Nickel Layer Interference

6. If there is a nickel plating layer on the copper plating layer, whether the nickel is over - corroded to the copper will cause the electrolytic thickness of the copper to become thin.

7. 4.Rubber Gasket Wear

8. If the rubber gasket is worn, the electrolytic thickness measurement value will be too large (Figure 3).

9. 5.Stirrer Malfunction

10. If the stirrer of the electrolytic thickness gauge does not rotate, copper can still be seen after the test is completed, and thus the copper thickness will also be thin.

11. 6.Electrolyte Selection

12. Plastic/Steel/Nickel Substrates: Use H4 electrolyte for copper plating layers.

13. Zinc Alloy/Brass Substrates: Use E4 electrolyte for copper plating layers.

14. Chemical Copper Plating: Use S4 electrolyte for Electroless copper deposition.

15.