Impact and critical factors in Heijunka implementation an action research study

Purpose: Although Heijunka (production levelling or smoothing) is a lean tool designed to balance changing customer needs and production efficiency, this study aims to analyze the impact of Heijunka and identify various factors which can generally affect its successful implementation. Design/methodology/approach: We adopted an action research (AR) approach to analyze the consequences of implementing Heijunka in a factory that successfully operates in a lean environment but faces demand that is increasingly less predictable, and customers who require ever more individualized products at low prices with extremely demanding delivery timescales. An estimation of costs was carried out to compare three alternative production planning scenarios: (1) make to order (MTO) production, (2) weekly levelled production and (3) production with minimal changeovers. Findings: The analysis of the impact of implementing Heijunka in this factory demonstrated that MTO production planning without Heijunka is the most efficient option for the factory. We explore the reasons why Heijunka is not suitable for this factory even though other lean principles and tools have been successfully implemented. In this way we identify the main factors which might influence the successful implementation of Heijunka, such as changeover time, the number of different product types (and lot sizes) and the capacity that the production lines are running at. Originality/value: Based on close collaboration between researchers and practitioners in the field of Operations Management, this AR study provides important information for decision making in lean environments (applying Heijunka or not), as well for the advancement of the academic debate about successful lean implementation nowadays.