Cost efficient design for welded brackets : for Wärtsilä engines

Abstract

This bachelor’s thesis was made for Wärtsilä Finland Oy, Marine Power Solutions. The aim of the thesis was to examine cost-efficient solutions for welded brackets for Wärtsilä engines. Welded brackets are common components for Wärtsilä engines, and are used for applications such as fastening of mechanical components, automation equipment, covers, pipes etc. Brackets are typically tailormade for an engine, depending on its function and surrounding constructions. Some brackets are made for large series of engines and remain in production for several years, while others are made for one single specific customer delivery project. Due to the different applications the size and shape of brackets vary. The material typically used is structural steel. Some brackets weighs less than 1kg while other supports can be up to 50kg or more. Manufacturing processes can be such as thermal cutting, bending, stamping, machining, welding etc. In practice, this means that there are thousands of different designs, and that the price of brackets varies a lot. The purpose of this thesis was to improve understanding of what are the main cost drivers of welded brackets and increase general knowledge of cost-efficient solutions.

The thesis is based upon theory related to Product development, Design for Manufacturing principles, and on relevant design guidelines. The thesis includes a qualitative case study of seven brackets selected by the commissioning company. The purpose of the qualitative study was to identify cost drivers related to current designs. Based on the findings from the qualitative study, and on theory from the literature review, proposals for new concepts were made for one of the brackets. The purpose of the concept generation was to explore a more cost-efficient approach to that selected design. As a result, the thesis concludes how the different designs affect component price, and a proposal for two new conceptual designs are made.