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Redesign of component assembly
2007 (English)Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

This Master’s thesis is performed at ZF Lemförder in Adelaide, Australia. The plant manufactures rear axles, front corner modules and steering columns for GM Holden. ZF Lemförder started the production in July, 2006 and because the plant is new some processes are still not optimal. The scope of this project is to redesign the component assembly area which provides the two existing main assembly lines with seven different subassemblies. Increasing the efficiency and making both the ergonomics and organisation better, are the main objectives during this project. To get the best results, methods such as Simplified Systematic Layout Planning (SSLP), Ovako Working posture Analysis System (OWAS), time study and benchmarking are used. A cyclic work procedure called the project spiral is used which makes it easy to go back and revisit certain stages of the project again. The task of making a new layout for this area is the major part of this Master’s. With the help of SSLP four block layouts (T-form, W-form, Centred and Straight) are made. They are evaluated and the Straight layout is the winning concept. Therefore it is decided to recommend ZF to implement the Straight layout in a later stage. Before the Straight layout is ready to be implemented it must be planned in more detail. After the layout is done, other problems at the component assembly have to be considered. These problems consist of how the material handling could be made efficient and easy, what can be done to make the ergonomics better and how the production could be more visual. A production board is a good and easy way to get an overview of how the production is going. The board holds information such as, how many parts that must be made during the shift and how many parts that the press area has produced so far. Another action that makes the production more efficient is educating operators in how to perform a tool change. This will minimise the time to perform a tool switch. To make the material handling of the component boxes simple and effective, a Kanban-buffer is installed along one long side of the area next to the main forklift aisle. This buffer is refilled by the forklift drivers from the main aisle, the boxes are then taken to the machines by the operators from inside the area. The trolleys that are used for transporting the finished products to the main lines are mainly stored at two large additional areas near the component assembly area. Other required material is stored behind the presses which makes it easy to obtain whenever it is needed. There are three major ergonomic issues: first the trolleys used for transportation are too heavy to manoeuvre for the workers. New wheels with a hard nylon surface and smaller contact area against the floor are preferred. If that solution is not enough, some of the trolleys have to be halved in size to make them lighter. Other activities that lead to unhealthy body postures are the high lifts when loading bushes into the presses and obtaining material from the inside of the large component boxes. These two problems are easily remedied by installing step up platforms for the loading of bushes and by using pallet tilters when obtaining material from the boxes. After the recommendation ZF decided to implement the concept during the long shutdown which occurs between December 18, 2006 and January 15, 2007. In the first stage the major changes are introducing a production board, a new layout, the Kanban-buffer and improving the trolleys. In January 15 the production starts smoothly according to schedule with the new improved layout.

Place, publisher, year, edition, pages
2007.
Keyword [en]
Technology
Keyword [sv]
Teknik
Identifiers
URN: urn:nbn:se:ltu:diva-43993ISRN: LTU-EX--07/054--SELocal ID: 1cdf604c-93ca-4e3e-8425-3c6e63c43f83OAI: oai:DiVA.org:ltu-43993DiVA: diva2:1017267
Subject / course
Student thesis, at least 30 credits
Educational program
Ergonomic Design & Production Engineering, master's level
Examiners
Note
Validerat; 20101217 (root)Available from: 2016-10-04 Created: 2016-10-04Bibliographically approved

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