Value Stream Mapping for Make-to-Order Products in a Job Shop Environment

Abstract

This paper investigates the use of Value Stream Mapping (VSM) for make-to-order products in a job shop environment, specifically the fabrication of Heating Ventilating and Air Conditioning (HVAC) sheet metal ductwork. The use of VSM for analyzing the production of repetitive units has proven to be successful in different industries. The use of VSM for studying the production of non-repetitive units requires some adaptation from repetitive-unit uses in order to successfully capture the attributes of multiple product families required at different frequencies and volumes. The VSM for a job shop environment has to be flexible to deal with the dynamic nature of job shops, e.g., maps may change daily according to the products scheduled for fabrication. Other aspects of the production system for sheet metal ducts that should be captured in the maps include the availability of a multi-skilled workforce for shop and site work, single flow of product and worker, and development of forecasts and capacity allocation to deal with frequent changes on incoming orders from project sites. Besides discussing the peculiarities of this job shop environment and their representation in a VSM, the authors discuss the process for elaborating VSMs for this production system and the definition of data used to develop them. Finally, the authors present a VSM for the fabrication of sheet metal ducts and discuss it using Lean Production concepts and recommend systematic data collection to reveal current practices and opportunities for improvement.