Six Sigma DMAIC project to improve the performance of an aluminum die casting operation in Portugal

Abstract

Purpose The purpose of this paper is to illustrate an application of the Six Sigma define, measure, analyze, improve, control (DMAIC) problem-solving methodology in a Portuguese industrial enterprise, aimed at reducing the rejection rate of a specific manufactured product due to defects generated in an aluminum gravity die casting operation. Design/methodology/approach Along the five-stage roadmap, a set of analytical and conceptual tools was systematically employed to better characterize the problem, define the product’s critical to quality characteristics, estimate the process baseline, determine the relevant cause-and-effect relationships, identify the root causes leading to the high rejection rate, implement an improvement plan, determine the effectiveness of the improvement actions, and put in place a control plan. Findings The project team discovered that the high rejection rate was caused by factors inherent to the gravity die casting operation itself and by the mixing of rejected parts made of different types of alloys from other locations within the plant. Another key finding was that the successful execution of the project was only possible due to the belief and support of top management and to the active involvement of the team members. Practical implications This case study illustrates a successful practical application of a Six Sigma project in a small-medium enterprise in Portugal, as well as the operational and financial benefits that derived from it; thus providing a good example for others to follow. Originality/value Few cases of continual improvement initiatives, including Six Sigma projects, developed at a Portuguese company are available in the literature; this paper fills such void by describing a very successful application that demonstrates the advantages that other companies can learn in terms of adopting structured methodologies to improve the quality of their products and the efficiency of their processes. Moreover, the analysis and conclusions herein presented can be of great importance for companies using gravity die casting technology.

Green implementation of Lean Six Sigma projects in the manufacturing sector

“…At an operational level within the manufacturing sector, the LSS model aims to clarify the process of identifying opportunities, as well as reduce variability and improve the quality of the manufacturing process (Muganyi et al, 2019;Holmes, et al, 2015). By utilising the LSS five-phased systematic methodology of DMAIC (Define, Measure, Analysis, Improve, Control), integrated with five general phases of project management (initiation, planning, execution, control and closing), manufacturers can tackle their own specific problems (Walter and Paladini, 2019;Sreedharan and Sunder, 2018;Marques and Matthe, 2017;Tenera and Pinto, 2014;and Gupta, et al, 2012). One of the most crucial steps of the LSS project is to identify the customer demand or voice of the customer and translate it to a prioritised Critical to Quality (CTQ) metric (Tenera andPinto, 2014 andLighter, 2014) that serves as the outcome variable.…”

“…LSS is formed with the balanced integration of Six Sigma as a systematic and rigorous tool to uncover and reduce defect and variation in breakthrough projects and Lean Management, with continuous incremental reduction of waste, environmental and economic sustainability, increasing the speed of the operation and delivering the value(Muganyi et al, 2019;Gijo et al, 2018; Tortorella et al, 2018;De Freitas and Gomes Costa, 2017;Marques and Matthe, 2017; …”

“…This obliges researchers and managers in the manufacturing sector to enforce more consideration into the environmental impact of the actual LSS projects. This means, in addition to benefits of LSS for green manufacturing, the barriers or conflicts to make the LSS project and methodology greener, also need attention.The systematic roadmap of DMAIC for continuous problem solving and enhancement with different stages and extensive use of resources may create an environmental conflict as sustainability detrimental impact(Sreedharan and Sunder, 2018;Marques and Matthe, 2017;…”

Lean Six Sigma and Performance Metrics

“…Lean Six Sigma focuses on metrics; it is a combination of set of statistical tools as DMAIC of Six Sigma employed in order to define, analyze, measure, improve, and control process variability as presented in Table 4 and critical-to-quality (CTQ ) (Lean) for customer requirement [23].…”

Reducing the Scrap Rate in Manufacturing SMEs Through Lean Six Sigma Methodology: An Action Research

“…It was evident from recent research studies that despite clear potential significant impact, LSS deployment in the automotive sector to reduce scarp rate suffers with neglect in both practice and research [53]. By utilising the LSS five-phased systematic methodology of DMAIC (Define, Measure, Analysis, Improve, Control) manufacturing SMEs can tackle any process variation and defect including scrap level [31,49,[53][54][55][56]. This standard improvement model is extremely helpful for any organisation because of providing a systematic road map [5].…”