Research On Lead Free Soldering For Surface Mount Technology

On the purpose of environment protection, two legislations -WEEE(Waste ofElectrical and Electronic Equipment)and RoHS(Restriction of The Use of CertainHazardous Substances in Electrical and Electronic Equipment )in Euro has been setup recently, which will be effective on July.1st, 2006. In coordinate with therequirement, there are worldwide activities that all electronic factories are busilyengage in turning their products lead-freely. Under this background and combinationwith our company lead-free manufacturing without any equipment and instrumentchanging requirement, the article includes the study of the lead-free solder paste andrelative lead-free production with focus on the critical process, and the optimizing ofprocess parameter and ensuring of production reliability by introducing several newdesigns of experiment. The achievements of the study have significant meaning forthe reference and utilization. The achievements as below:Compared lead/lead-free solder paste about their ingredient and characteristics, andanalyzed the relative influence to the products and production. Designed solderprinting comparison experiment and printing result observation numeric experimentto identify the process-optimized parameters of screen print.Introduced 9 curves design of experiment for confirming reflow workingprocess-optimized parameters.Validated the effectiveness and reasonable of the process parameters by completinglead-free products pilot run and the relative reliability testing.