Troubleshooting of plastic plating processes
The use of plastic parts instead of metal parts is an important measure to reduce the weight and fuel consumption of automobiles. Although plastic parts have the advantages of light quality, easy forming, low cost and corrosion resistance, they also have the disadvantages of being less strong, weather resistant and decorative than metal parts. In order to adapt to the decorative requirements of high-end cars, many automotive plastic parts need to be plated, stamping, watermarking, painting and other surface treatment.
The quality of plastic plating, not only with the plating process, but also its material, forming process has a close link.
During the plating of a plastic sign for a prototype car, we encountered an unexpected difficulty. The plastic prototypes sent to us by the matching factory
The plastic sample sent to us was not a regular injection moulded part, but a machined and polished sample on an abs (Taiwan 757) injection board.
We use the following conventional plastic plating process for plating.
Internal stress relief heat treatment → chemical degreasing → washing → roughening → washing → sensitisation → washing → activation → washing → reduction → washing → chemical copper deposition → washing → electroplating without bright nickel → washing → acid bright copper → washing → bright nickel plating → washing → chromium set → washing → washing → blowing dry.
The sample was normal in appearance before roughening, and the surface roughness was low, but once the roughening process was completed, several yellowing spots appeared on the surface, and the plating was blackened in the area when the copper was chemically immersed, and there was a leakage after plating. Despite repeated adjustments to the roughing process conditions, extending the heat treatment time to eliminate internal stress and strengthening the reduction process, little success was achieved. After the investigation of the blank production process, it was learned that the sample blanks were made of abs injection moulding board, and there was always a small amount of black pc material inclusions on the injection moulding board because the chamber of the injection moulding machine was not cleaned up. Although by in the mechanical processing and polishing, the surface can not see defects. But in the roughing process due to the stress in the area is relatively large, it is easy to over-roughing, the formation of micro-fine cracks or sparse
