Efficient Line Changeover: The Key to Lean Manufacturing

ABSTRACT Changes in the domestic printed circuit board assembly industry have resulted in a dominant shift to a high-mix, low-volume (HMLV) manufacturing environment resulting in a high frequency of line changeovers. Reducing changeover duration and optimizing the changeover process are critical ingredients to an efficient and profitable domestic HMLV operation. For extreme HMLV applications such as new product introduction (NPI), prototyping or short run manufacturing, changeover efficiency is an absolute necessity. Implementing lean manufacturing practices is essential to reducing the accumulation of work-in-process inventories that are prevalent with a HMLV manufacturing environment. Putting into practice a single-minute exchange of die (SMED) philosophy is a vital component toward reducing non-value added changeover time since it has significant impact on the implementation of lean manufacturing practices. This paper addresses the root cause of non-revenue generating line stoppages such as feeder setup, substrate support setup, programming, tooling changeover, equipment maintenance and breakdown, and process corrections. A case study will be presented that analyze the economic impact of line changeover in terms of hourly revenue per SMT line, burden cost per hour and line optimization rates. The proper selection of tools and procedures to reduce the setup process time for screen printers, pick and place machines and dispensing equipment is necessary to insure minimal changeover durations and increased line uptime.