Value stream mapping and discrete event simulation applied to reduce waste in a company that manufactures a family of automotive parts

Lean manufacturing seeks consistent and complete elimination of waste in order to optimize resources. However, the elimination of such waste in most cases is done through of trial and error, which usually entails more costs for the company. Given this scenario, this paper describes the use of Value Stream Mapping (VSM) and Simulation to a family of products in a company that produces machined parts for the automotive sector. This family corresponds to five models of different cylinder heads that undergo similar processing steps and use similar equipment in their processes. In order to identify waste, initially the current state value stream map of the system that manufactures the family of cylinder heads was developed, and thereafter the future state map was built, seeking to reduce or eliminate waste and implement a lean value stream. The future state map was also modeled in a simulation software, in order to evaluate the proposed improvements in the future state and propose scenarios that enable adequate decision making by the managers of the company, such as the event of an increased demand. The use of simulation together with VSM contributed to provide the following additional advantages to using only VSM: (a) use of random data in the analysis of the results, (b) the possibility of modeling different scenarios without changing the physical arrangement of the production line. The results obtained by applying the methods to the cylinder head manufacturing were: reduced lead time, increase in utilization rates, improvement in visual management, and increased productivity. In addition, the production line started to operate with the amount of operators needed to satisfy the demand.