Lead-free soldering process for coil terminals by using atmospheric pressure plasma technique

Recently, much attention is paid to the environmental problems caused by lead”, and practical use of lead-free solder is especially accelerated in the field of printed writing boards. However, lead solder commonly used for terminals of coils hasn’t yet replaced by lead-free solder. From solder-plated terminals, lead flows into the lead-free solder bath during wave soldering process, so we are faced with a problem of lead concentration in a solder bath. Conventionally, it is possible to plate coil terminals with lead solder by dipping it into the solder bath, but such a procedure cannot be applied to lead-free solder. So the process of removing insulator film coated on a copper wire and plating the treated copper wire with lead-free solder is strongly required.