The Study Of Lead-free Soldering Quality Improvement For Company L

Six Sigma has been proved to be an effective management tool by lots ofinternational companies. In recent years, more and more companies have begun tophase in Six Sigma. As a subsidiary of GE, company L is also without exception andvalue highly regarding of Six Sigma Management.Based on this, this thesis selects a product which has been boring the companyfor a long time with high defective rate and high scrap rate as a Six Sigmaimprovement project. Firstly, we analyzed the defects data of the second half of2012.We found that67.1%of the defects were caused by lead-free PCB for poor solderingissue. Then we used the tree diagram to analyze and identify the project target----improve the HASL (hot air solder leveling) thickness of the PCB. On this basis, weworked with PCB suppliers to carry out a Measurement System Analysis (MSA) ofsolder paste’s thickness measurement. Once the MSA was confirmed in available, weselected4parameters (air knife’s temperature, pressure, angle and the distancebetween2knives) which would impact on HASL thickness to do DOE. Per DOE, wedetermined the optimal parameter settings. And then we used the optimal parametersettings to do a trial run for30pcs PCBs. The result showed that HASL CPK wasincreased from0.15to1.08by measuring the solder paste’s thickness of PCB. Thedefective rate for poor soldering issue is reduced from1.85%to0.09%. The total costsavings is$28,972.This research of thesis not only improves the product yield rate, reduces the costof scrap, but also enhances the collaboration among project team members.