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Workflow balancing on a shop floor helps to remove bottlenecks present in the manufacturing system. Workflow refers to the total time during which the work centres are busy. Idle time is not taken into account when calculating workflow. Earlier researchers have not specified the method for jobs to be executed in parallel in order to balance the workflow to each machine. In many manufacturing environments, multiple processing stations are used in parallel to obtain adequate capacity. In parallel machine scheduling there are m machines to which n jobs are to be assigned based on different priority strategies. The procedure is based on the idea of workload balancing and on balancing the workload among machines. In this paper, workflow and workload are assumed to have the same meaning. A machine with the lowest workflow is selected for assignment of a new job from the list of unfinished jobs. Different priority strategies are followed for the selection of jobs. Three different strategies are considered, namely random (RANDOM), shortest processing time (SPT) and longest processing time (LPT) for the selection of jobs for workflow balancing. The relative percentage of imbalance (RPI) is adopted among the parallel machines to evaluate the performance of these strategies in a standard manufacturing environment. The LPT rule shows better performance for the combination of larger job sizes and higher number of work centres or machines. A computer program was coded for validation in a standard manufacturing environment on an IBM/PC compatible system in the C++ language.

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Variation in product performance can be seen as a design failure. The fundamental principle of robust design proposed by Taguchi is to improve the quality of a product by minimizing the effect of causes of variation, without totally eliminating the causes. A method of robust design is briefly explained and its application is demonstrated with the help of a case study from Roots Industries Ltd., Coimbatore. This paper describes how the inherent modeling of product and process requirements in key characteristics (KCs) can be used to express and capture the product design intent. KCs are those features which significantly affect product function and performance, or occur when there is variation. A prototype software program (VRM Tool) was developed to house all the critical design data for process optimization and its eventual reuse. We establish a systematic process of identifying, assessing and mitigating risk in the early stage of design for a Windtone class of automobile electric horn, using robust design concept. The results suggest that the proposed robust design method is an efficient, disciplined approach that can assist a product delivery team in designing for a better functional performance and improved reliability of the entire system.

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