An oxide-reduction structure, jet nozzle structure, etc. were devised for lead-free solder packaging in the manufacture of small circuit boards for shavers. These structures were then used in a practical application and mass-production of lead-free products was achieved. The resulting connection quality was confirmed to be equivalent to that of conventional lead solder processes. The packaging process for the three circuits (charging control circuit, drive control circuit, and charging circuit) involved consists of various processes, including flow, reflow, hot air flow, and manual soldering. Problems in each of these processes were solved, and as a result of setting the optimum temperatures and optimizing the control standards, it was possible to maintain reliability and apply the packaging system to mass production.
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