THE ECONOMICAL DEVELOPMENT OF A LEAD-FREEASSEMBLY PROCESS: A PRACTICAL CASE STUDY THAT MINIMIZED CONVERSION AND OPERATIONAL COSTS

摘要

This paper documents the successful development of a lead-free assembly process capability that was undertaken at a small full service electronic manufacturing facility (EMS) company. Each element in the circuit board assembly process, from material procurement and paste printing to wave soldering, hand soldering and cleaning, is analyzed. The options for each element that was considered and weighted are discussed in terms of their estimated costs and corresponding benefits (both recurring and non-recurring). A successful conversion protocol from lead-bearing solder (Tin/Lead eutectic) to a lead-free alloy (SAC 305 for reflow and SAC 307 for wave) is presented as a suggested blueprint for operations that do not have the depth of resources of larger companies. Throughout the text common industry doctrine is highlighted as "Industry Direction." These statements are followed by empirically derived challenges: i.e., alternatives to this direction presented as recommended "Decision Making Guidelines" and accompanied by the corresponding "Cost Impact." In addition to equipment and process decisions, also discussed are the material considerations (e.g., alloy selection, material considerations, bare board options) and logistics issues such as part numbering and inventory considerations that were an integral part of the total conversion process.