Applying lean manufacturing system to improving productivity of airconditioning coil manufacturing

摘要

The main objective of this investigation was to implement lean manufacturing system (LMS) to improve productivity of airconditioning coil manufacturing at Blue Star Limited. LMS was successfully employed to improve coil manufacturing productivity or output by 77% or from 121 coils to 214 coils per shift. The LMS tools; such as value stream mapping, single minute exchange of die, and Kaizen were employed to reduce the setup time of coil expander machine from 60 to 20 min, an improvement of 67%. The increase in percentage value addition (%VA) of the coil shop was from 5 to 12%, an improvement of 140%. The improvement, especially in coil expander machine was achieved through Kaizen (continuous improvement) targeting design and work method changes. The specific innovative design changes or improvements made in the expander machine to reduce the setup time included the application of: (1) gear rack and gear pinion mechanism, (2) spring and cam and lever mechanism, and (3) one touch mechanism in the various components of the machine. Many method Kaizens were also proposed to simplify the setup procedure by eliminating waste (muda) from the setup of expander. Other benefits were obtained through reduction of work-in-process inventory, which in turn reduced the shop floor congestion and coil damage due to extra coil handling and improved workplace safety.