The Materials Analyst

摘要

Some years ago,one of the process engineers I was working with brought me some parts being molded in a 33% glass-fiber-reinforced nylon.The parts had an unusually poor surface appearance,with glass fibers evident on the surface.The typical samples archived in the quality control department showed a resin-rich surface,indicating that something was not normal.In these types of situations the debate usually ensues about material quality vs.process as the root cause.The engineer was expecting a full-blown composition analysis of the material and was almost certainly expecting that we would find that the material was out of specification on the high side for glass.However,our first and last test was a check ot the moisture content in the material.A Karl Fischer titrator showed that the moisture content of the resin was 187 ppm,or about 0.019%,.