A COMPARATIVE-STUDY OF LINE DESIGN APPROACHES FOR SERIAL PRODUCTION SYSTEMS

Over the past decade two approaches, just-in-time (JIT) and theory of constraints (TOC), for designing and operating production lines have d eveloped, each claiming to be the ''correct'' way. In addition there a re still those who maintain that line balanced (whenever possible) is the optimal method. This study uses simulation to compare each of thes e approaches for designing and operating production lines under variou s levels of processing time variability, station downtime, and total s ystem inventory. Not surprisingly, the JIT approach appears to work be st when system variability is low. The TOC approach works best when sy stem variability is high. This shows that lines designed using TOC pri nciples perform significantly better than JIT lines when inventory is low, and JIT lines perform significantly better than TOC lines as inve ntory is added to the system. The traditionally balanced line did not perform best under any of the conditions used in this study.