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Throughput Time Optimization in a Production Flow: A Case Study in the Power Wheelchairs Industry
2016 (English)Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

This report is a master thesis conducted during the spring semester of 2016 as a final part of the Masterof Science in Industrial Design Engineering at Luleå University of Technology. The aim of thisthesis was to map and analyze the production flow of Permobil in Timrå, Sweden. This was done inorder to deliver concrete solution proposals in the end of the project, which lay within the Lean philosophyand are adapted to Permobil’s production categorized as high-mix and low-volume products.The overall objective has been to optimize Permobil’s production flow in order to reduce the throughputtime for their products.Permobil is a world leading manufacturer of electrical wheelchairs. Their vision is to stand up for theircostumers’ rights and provide the best possible solutions. For Permobil Timrå to be able to follow thedemand and increase its annual production from the current annual 4,600 chairs to an annual of 7,700chairs in 2018, the production must be more effective. Since the production in Timrå is characterizedby a high-mix and low-volume, problems can occur when reducing throughput time since provenmethods are not always suitable for this type of production.Implementation of the thesis has followed a cyclical approach through the project circle. To create abasic understanding of the work, a theoretical framework was conducted containing subjects as LeanProduction, challenges of implementing Lean, high-mix and low-volume, work in progress and pushand pull system. Mapping and analyzing the current situation was carried out through observations,unstructured interviews, a Deviation Analysis and Value stream mapping. The analysis resulted in arequirement specification that pointed on the requirements of future solutions would come to meet.The main requirements were estimated to good physical and psychological work environment, meetthe customer´s need and increased product flow. Workshops and brainstorming has been used to developand evaluate solution proposals.The mapping and the analysis of the current state show that the products spend an average of 90 %waiting. This waiting time consist mainly of the high number of work in progress and difficulties insynchronizing the different departments with each other. Inadequate communication and order problemshave also been identified as a problem and may occur due to the lack of standardized work. Thefinal concept is developed in the Custom station.The final concept provides a meeting place between the Custom station and the order department forexchange of perspectives regarding the order data. A help signal that indicates if the worker at theCustom station needs help which would mean that the problems with the order data is moved closer tothe original source. Moving short customization job in order to facilitate a better flow of chairs. Implementa sale document involving standardized order data. Implement a modified CONWIP system,which mean a controlled desirable level of work in progress. Log times so that the data could be storedon the customization jobs. These solutions contribute to better communication, elimination of orderproblems, an evener flow, elimination of unnecessary transport and misunderstanding, and more credibleorder data. All these solutions together in a concept meets the requirement specification in theshort and long term, and together they will minimize the throughput time with 7 hours and release 5hours per week in resources. Our recommendation is to implement the final concept and to involveemployees in the development work.

Place, publisher, year, edition, pages
Keyword [en]
Keyword [sv]
Teknik, Genomloppstid, Lean Production, hög variation och låg volym, värdeflödesanalys
URN: urn:nbn:se:ltu:diva-49767Local ID: 714c6d2c-6530-40dc-aac7-e23d71ec9992OAI: diva2:1023114
External cooperation
Subject / course
Student thesis, at least 30 credits
Educational program
Industrial Design Engineering, master's level
Validerat; 20160623 (global_studentproject_submitter)Available from: 2016-10-04 Created: 2016-10-04Bibliographically approved

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