Since its beginning, lean manufacturing has built a worldwide reputation based on results related to production improvement and cost reduction in several companies. This management philosophy focuses on customer value creation through the elimination of production wastes. Lean methods and techniques have spread their scope from the automotive industry to a wide range of industries and services. This article presents a case study that describes the use of the lean tool value stream mapping in the production process of automotive parts for a major automotive company. At the beginning of the project, relevant data from the process were collected and analysed. Subsequently, the initial process was mapped, the related wastes were identified, and then future processes were mapped and financial results were estimated. The proposals were presented on kaizen meetings, the action plan was discussed and the decision regarding which option to choose was taken. Consequently, the Cycle Time and the level of the workforce were reduced, the process was improved and savings were obtained.Keywords: lean manufacturing; continuous improvement; value-stream mapping; automotive industry; plastic injection
IntroductionThe economic crisis that Europe currently faces has had a huge impact on companies' revenue. In order to strive through this period, many were forced to implement cost-saving management philosophies; one among them is lean manufacturing. Lean manufacturing is based on the principles of the Toyota Production System (TPS). In essence, lean manufacturing philosophy focuses on customer value maximisation through the elimination of production wastes (Womack and Jones 2003; Belekoukias, Garza-Reyes, and Kumar 2014). Contrary to product standardisation and assembly lines, lean thinking promotes small production lots and quick changeovers thus reducing production time and focusing on product quality and diversity at a competitive price (Womack, Jones, and Roos 1990; Rahani and al-Ashraf 2012). This article describes the work that was carried out in a Portuguese original equipment manufacturing company, operating in the injection moulding industry, that supplies major automotive companies. A mid-to long-term strategic decision led the company to invest on a production project of plastic parts for a luxury car of a current customer. The work was carried out during a period of 8 months, and its main objective was to improve the performance of the production process, through the reduction of wastes and thus increasing its quality and efficiency.In order to achieve the proposed objectives, firstly lean manufacturing and continuous improvement methods, mainly value stream mapping (VSM), were analysed and considered. Afterwards, production data related to the project, both from documentation and on-site, were collected and analysed. Subsequently, the following steps were followed: (i) the mapping of the current production process and the identification of critical points, (ii) the mapping of the desired production process together with...