Reducing the Set-Up time in a CNC machining line using QCO methods

Setups determine downtime, capacity, product quality, and to some extent costs. As much as 60% of effective capacity can be lost to setups in machining lines. A SMED will help to eliminate unwanted activities, assists to move internal set-ups to external set-ups. The applications of other specific tools such as Poka-yoke, 5’S and the specially designed Quick change fixture and Quick change jaw mechanisms can further bring down the set-up time considerably low. The low changeover time will result in increased manufacturing flexibility for SME's.

The purpose of this study is to find out the significance of quick changeovers in machining line. The Set-up activities are a vital part of the production lead-time and so affect overall product cost. Tools like Pareto analysis, rootcause analysis and method study have been used to analyze the existing procedure of set-ups. Based on the initial studies the pallet system was proposed for vertical machining centre as quick change fixture base on which the existing stage fixtures are located. Similarly the quick change jaw system was proposed for the turning centre. The fixture mechanisms were designed to eliminate 40% unwanted activities in the design stage itself.

The Quick Change Fixtures and Quick Change Jaws were designed and validated thru real time simulation. To achieve manufacturing excellence, SME's must take advantage of latest technological developments to improve the productivity and profitability. The right implementation of the SMED can even become a competitive advantage of any SME's; this would bring the more business to the organization. The report confirms that the seemingly extreme benefits claimed by SMED are achievable, but only with the assistance of modern technology. Results show reduction of average set-up time from 108 minutes to less than 16 minutes. We conclude that using SMED, the machine availability can be increased.