When chrome plating on plastic substrates, one of the most important factors in the success of the process is the quality of the molding. Poor quality moldings will yield poor results; in fact, it’s said that 50 percent of problems associated with plating ABS plastics are the result of faulty molding or design.
Many parts plated for automotive applications are required to pass thermocycling tests. The plating distribution, resin characteristics, pre-plate process, molding characteristics, and part geometry will affect how the part will respond to extreme temperatures.
For optimal plating results, moldings should have cross-sectional dimensions with minimum variation, and wall thicknesses should not exceed 3.8mm, to avoid uneven cooling and shrink or warp of the component. Introducing ribs to the molding design can add strength and rigidity to a component without adding weight and increasing wall thickness. Generally, components to be plated should have gently curved, convex surfaces, without sharp edges, which may cause plate build up (flash). Deep recesses are also not advisable, as they cannot be plated without the use of special anodes.
Some problematic design features to avoid:
- Sharp angles (90 degree angles)
- Sharp edges
- V-shaped grooves
- High ribs or bosses
- Raised or depressed lettering
- Closed ring design
- Solid plastic parts with heavy mass-to-surface area
Want to know if your molding design is conducive to plating? Call ECF for a quote!