Uniformly Depositing Plating Material on Plastics
The resurgence in demand for plating on plastics in recent years has led manufacturers and metal finishing companies to seek ways to improve the process. A primary focus area has been creating a more uniform coating of the metal onto the plastic substrate — which has been a trouble spot since the development of plastic plating in the 1960s.
What Causes an Uneven Surface When Plating Onto Plastics?
Uneven surfaces can occur for several reasons. The most common cause is the formation of particulates in the electrolyte plating solution. The electroplating process will deposit these foreign materials onto the substrate, which can lead to roughness in some areas. In most cases, filtering the bath will remove most or all of the particulates.
Electroplating requires the introduction of a DC electric current into the plating solution. If the current density is too high, it also can create a rough surface on a plastic workpiece. Another typical issue that leads to uneven plastic surfaces is failing to develop a bath formula with the correct stannous level or pH balance.
Electroless Plating Can Help to Prevent Uniformity Problems
For these and several other reasons, most metal finishing companies choose electroless plating when coating plastic workpieces. Unlike conventional electroplating, the electroless method does not require an electric current — coating occurs via an autocatalytic reaction, which eliminates the high current density issue. It’s also easier to control and maintain the composition of the bath, which helps to prevent problems related to inadequate bath formulations.
Another benefit of electroless plating is the ability to control the thickness coating. When executing an “all-over” plating technique that requires immersing the entire workpiece in the bath, it’s possible to achieve a uniform thickness across the surface (range is from 40 to 2,000 micro-inches). The ability to create a thickness to meet virtually any manufacturing requirement is a significant advantage when considering electroless vs. electroplating onto plastics.
The Importance of Material Selection
Also, choosing the right materials can help to reduce the likelihood of uneven surface coatings. Plastics that work well with plating include acrylonitrile butadiene styrene (ABS), Teflon, phenolic (laminates), polycarbonate, polyoxymethylene and polysulfone, all of which have widespread use in many industrial manufacturing applications. Metal selection can also play a role in achieving surface uniformity — preferred metals for coating plastic include gold, nickel and copper.
SPC Can Perform Plating on Plastic to Your Specifications
At SPC, we’ve perfected a process for plating onto plastics, and we can customize it to your company’s manufacturing processes. We know how to troubleshoot and eliminate the defects can lead to unsatisfactory results — including the lack of coating uniformity. Contact us for more information or to request a quote today.
