Efficient Metallizing of Complex Injection Molded Parts
Metallizing of three-dimensional molded plastic parts usually involves the steps of injection molding, pretreatment and chemical metallizing. In actual practice, the variability of these process steps results in considerable effort as regards parts handling. To reduce this effort, molded interconnect devices (MIDs), for instance, are treated in bulk in chemical metallizing baths. Under certain circumstances, however, delicate and mechanically sensitive parts face problems.
A recently published patent describes a newly developed process that permits exact positioning of the molded parts. It permits rapid and economical deposition of electroplated copper layers. A connecting piece holds the plastic parts to a flexible carrier, for instance, a conveying belt. In this way, a number of plastic parts are temporarily connected to one another. The connecting piece functions as the electrically conductive connection between the carrier and plastic part and provides the electricity needed for the metallizing process. The interconnected plastic MIDs can be transferred easily from one processing step to the next to be metallized.
Use of standard carriers with a fixed spacing facilitates flexible manufacturing. The need to modify processes is largely eliminated when metallizing different molded plastic parts. Singulation of the molded plastic parts takes place in a separate step, for instance, in conjunction with installation of the plastic part on an assembly. It is advantageous if the connecting pieces can be separated from the molded plastic parts at an intentional weak spot in the material. Laser cutting devices or punches are suitable for this purpose.