Selective Electroplating of 2-Component Parts
Plastic parts with electroplated surfaces have appealing visual and tactile properties. This is why they are used in numerous applications. It is difficult, however, to electroplate two-material parts, with hard and soft regions, since the soft material is damaged by electroplating bath if the entire part is electroplated. Under certain circumstances, components that are extracted from the soft material can cause undesirable effects in the electroplating baths. In addition, the soft material picks up substances from the baths that can migrate later. Irregularities in the transition zone between the hard and soft regions that blur the defining edge of the metal plating present an additional problem.
This is why, until now, electroplating of hard/soft 2-material parts has required several steps. After the hard part of the component has been injection molded, it is electroplated. Next, the plated part is placed in another injection mold, where the soft material is molded. This multi-step process often requires manual assistance and has a relatively high defect rate. The large investment associated with this approach is an additional drawback.
By using specially developed TPE materials, it is now possible to first produce the entire hard/soft 2-material part via 2-component injection molding and then electroplate it. This considerably faster process offers significant potential for savings with regard to mold and production costs as well as in terms of logistics. The risk of producing nonconforming parts is reduced considerably – for instance, the defect rate during electroplating is less than 3%. In addition, this improved approach provides greater part design freedom.
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