Building a foundation for proactive quality management Analysis and improvement of a manufacturing process using Lean Six Sigma Master’s thesis in Engineering Mathematics and Computational Science, and Quality and Operations Management HENRIK EDMAN JOAR HUSMARK DEPARTMENT OF INDUSTRIAL AND MATERIAL SCIENCE CHALMERS UNIVERSITY OF TECHNOLOGY Gothenburg, Sweden 2020 www.chalmers.se i Building a foundation for proactive quality management Analysis and improvements of a manufacturing processes using Lean Six Sigma © HENRIK EDMAN, 2020. © JOAR HUSMARK, 2020. Department of Industrial and Material Science Chalmers University of Technology SE-412-96 Gothenburg Sweden Telephone + 46 (0)31-772 1000 Gotheburg, Sweden 2020 ii Acknowledgements We would like to thank our supervisor Peter Hammersberg for his support and guidance throughout the project. Since the project utilized the Six Sigma methodology, his expertise and experience helped us greatly. We would also like to direct a special thanks to our supervisor and company contact at the case company for his continuous help and support. Although busy, he always made time to help us when needed. Furthermore, we would like to thank all who participated, in one way or another, making this project possible. Especially the employees from Company A, who willingly shared and discussed their experience with us. Finally, we want to thank our friends and family for their moral support throughout the entire project. This was especially important considering the abnormal circumstances caused by the Covid-19 pandemic. iii iv Building a foundation for proactive quality management Analysis and improvements of a manufacturing processes using Lean Six Sigma HENRIK EDMAN JOAR HUSMARK Department of Industrial and Material Science Chalmers University of Technology Abstract Imagine a manufacturing process where there will always be material available with flawless quality at the right time in the process sequence. Imagine that each operational activity would be carried out once, on time, with no lag or issue in between. For most companies, this is often far from reality. This report will cover a company case where issues are dealt with as they occur, in a reactive manner. The company under investigation is experiencing disruptions in their manufacturing process, causing both standstill and rework. The purpose of this thesis is therefore to identify the potential root causes for operational waste, and to help build the foundation for proactive quality management. The project was conducted using tools and theories from Lean Six Sigma and will contain a theoretical background, an explanation of the issue at hand, as well as an analysis of the current situation. Since the project was conducted using the DMAIC methodology, the current measurement system will be explained. Furthermore, the thesis contains an extensive analysis of both the currently identified process deviations and the underlying measurement system, as well as the identification of potential root causes for operational standstill, resulting in a new strategy for proactive quality management. The project resulted in the identification of a large number of current and potential root causes for process standstill. Since the current measurement system was inclined towards a more reactive approach to quality management, this was also addressed. In order to help build the foundation for proactive quality management, and to increase the knowledge within the company of the present causes for standstill, the team recommend the implementation and continuous usage of Process Failure Mode and Effect Analysis (PFMEA). Keywords: Six Sigma, PFMEA, LEAN, root cause analysis, process improvement v vi Table of Contents 1 Introduction ........................................................................................................................................... 1 1.1 Background ................................................................................................................................... 1 Purpose .................................................................................................................................. 1 Objectives ............................................................................................................................. 1 Delimitations ......................................................................................................................... 1 1.2 Ethical and Environmental Considerations ................................................................................... 2 2 Theory ................................................................................................................................................... 3 2.1 Lean............................................................................................................................................... 3 3 Methodology ......................................................................................................................................... 5 3.1 Empirical Study Utilizing DMAIC ............................................................................................... 6 3.2 Data Collection and Research Design ........................................................................................... 7 4 Define .................................................................................................................................................... 9 4.1 Effective Scoping .......................................................................................................................... 9 4.2 Value Stream Mapping ............................................................................................................... 11 4.3 State Analysis .............................................................................................................................. 13 Ideal State Analysis ............................................................................................................. 13 Current State Analysis ........................................................................................................ 13 4.4 Expanding Knowledge ................................................................................................................ 17 5 Measure ............................................................................................................................................... 19 5.1 Throughput time data .................................................................................................................. 19 5.2 Deviation document .................................................................................................................... 20 5.3 Shortage List Compilation .......................................................................................................... 22 6 Analyze ............................................................................................................................................... 23 6.1 Measurement analysis ................................................................................................................. 23 Deviation document analysis .............................................................................................. 23 Shortage lists analysis ......................................................................................................... 23 6.2 Deviation analysis ....................................................................................................................... 24 6.3 Root cause analysis ..................................................................................................................... 26 Affinity Interrelationship Method ....................................................................................... 26 Fishbone Diagram ............................................................................................................... 27 6.4 Material defects ........................................................................................................................... 28 External Material Defects ................................................................................................... 29 6.4.1.1 Shipping damage ............................................................................................................. 29 vii 6.4.1.2 Supplier Manufacturing issue ......................................................................................... 29 6.4.1.3 Blueprint issue ................................................................................................................ 29 6.4.1.4 Software error ................................................................................................................. 30 Internal deviations ............................................................................................................... 30 6.4.2.1 Instructions ...................................................................................................................... 30 6.4.2.2 Human error .................................................................................................................... 30 6.5 Material shortage ........................................................................................................................ 31 Supplier error ...................................................................................................................... 31 Rules and regulations .........................................................................................................