Plastic electroplating is the most common electroplating process in the electroplating industry. Sometimes after plastic electroplating, electroplated parts will have some undesirable phenomena. Next, let's introduce the undesirable phenomena and the corresponding analysis of their causes.
1. Incomplete deposition of electroless plating. Regular incomplete deposition of fixed parts is a manifestation of internal stress concentration. Plastic electroplated products should undergo stress relief treatment. Incomplete deposition occurs irregularly and randomly. First, find the cause from coarsening, and then possibly insufficient activation. Finally, the efficiency of electroless plating decreases. Correct the cause.
2. The electroplating layer is peeled together with the electroless plating layer. Insufficient roughening, bright chemical coatings and peeling of local fixed parts are often seen, which are points of internal stress concentration. The coarsening and stress relief should be strengthened.
3. Skinning between the plating layers. Bright plating, especially bright nickel plating, has high internal stress, which may cause the brightener to be out of balance. It is also possible that the pH of the nickel plating is too high or the intermediate plating layer is oxidized or passivated, which causes poor bonding of the surface plating layer. Adjust the plating solution and pay attention to the activation of the process of strengthening the intermediate plating. Change the activation solution frequently. During chromium plating, the parts will stay in the plating tank for a while before preheating and then electrify for electroplating.
4. The coating dissolves locally on the part. The hanger has poor conductivity and a "bipolar" phenomenon occurs, which makes the part of it become an anode and dissolve. Note that there should be more than two contact points between the hanger and the workpiece, and a good contact must be ensured.
5. There are burrs and pits on the ABS coating. The physical impurities deposited on the surface caused by the dirty plating solution may also be affected by copper powder and nickel-plated anode mud. The plating solution should be filtered regularly. All anodes must be protected by anode bags. During the production process, no parts are salvaged or the plating solution is stirred from the bottom. It should be covered when the plating solution is not used. The pitting of plastic electroplating products is mostly due to the low pH value of bright nickel plating, which intensifies hydrogen evolution and insufficient surfactants. Adjust the pH of the bath to the normal range, and add surfactants such as sodium lauryl sulfate to reduce hydrogen adsorption.
6. The parts are deformed after plating. After the ABS plastic electroplating is completed, some products are sometimes found to be deformed, which affects the assembly or use. For example, if the outer frame, cover, nameplate, and matching components are deformed, they cannot be installed and used. There are three reasons for this quality problem. One is that the design itself is unreasonable and there are design flaws. The other is the unreasonable design of the hanger. There is also lax process control and improper operation.
