Abstract
Wettability of lead-tin solder against metal surface jointed together is one of the important characteristics which affect soldering operation and strength.
Studies on a standardization of testing method of solder wettability by contact angle, which is one of the important inspection items for quality control of solders, are reported here.
The contact angles of melted solder drops on a test specimen in electric furnace were measured by goniometer dynamically during heating and melting them by a standardized procedure or also measured statically when they were cooled.
From results of various factorial experiments and analyses, it is found that lead-tin ratio of solder, melting temperature, fluxes, kinds of metals, cleanness of metal surface, etc. have effects on results, and especially both fluxes and kinds of metals influence them.
Standard error of contact angle measured by goniometer constructed by authers was about 10°, but it was found enough for contact angle used as a characteristics of solder wettability inspections.
