Increasing Short-Term Output in Assembly Work

Maximization of flexibility is one of the major challenges in assembly line design. This article addresses the question of how to temporarily (in times of peak demand) increase the output of a line, which is already optimized to attain the "normal" output rate. Instead of a costly reconfiguration of the line creating extra workstations for more operators, we applied an approach of keeping the line intact, adding two extra operators, and applying a scheme wherein the operators took their breaks alternately. For two different alternating break schemes, we compared the productivity rates, the physical load on operators, and the operators' experiences to those of the traditional situation. The new approach resulted in an increase in line output of 12-16%, depending on which alternating break scheme was applied. On the operator level, we observed no differences in productivity among conditions, despite the differences in total pause time per operator. Simultaneously, physical loads on the neck and shoulders, expressed by level of discomfort, were found to be significantly lower in one of the new alternating break schemes. A majority of the operators rated this alternating break scheme as "pleasant" (90%), but wanted the scheme to be applied only during the periods of peak demand because of social aspects (80%). In conclusion, an increase in volume flexibility can be achieved by adding two extra workers and applying an alternating work/rest scheme without a costly reconfiguration of the line. (C) 2010 Wiley Periodicals, Inc.