Redesign of a Shock Absorber Piston Using Sintering

Abstract: The main objective of this report is to re-design of a product by substituting for another manufacturing process in order to get a cheaper product with the same function and quality. The current shock absorber piston is manufactured by the machining process at Öhlins Racing AB Company. Power Metallurgy (P/M) method could be a good substitute process to meet the technical requirements of the current piston with total lower cost. In this case, the whole process of product development gets involved in designing two new pistons from base-design to final product. One design is assigned to a cheaper P/M process as called Conventional Press and Sinter. Another P/M process as called Metal Injection Molding (MIM) is considered to produce the more expensive piston. According to the design guidelines of P/M processes, the base pistons are modelled in a three dimensional environment, and then an appropriate powder metal is selected for each. Consequently, the next stage is to analyse the piston strengths by Finite Element Method under the static and dynamic loadings. Fatigue analysis is taken into consideration for the cyclic loadings, and the static strength can be assessed for the static loading mode. The results show the infinite fatigue life for two different designs, and no plastic deformation is observed during analysing of the pistons under static loading. Cost estimation is the last stage of this master thesis. Compared to the total costs for the current design, the total estimations for the whole final P/M products can prove the significant drop in the final prise for each design. Thus, environmental and financial issues are already met in achieving the new pistons in this project by saving considerably money and energy. On-going stages will be to make prototype and get them tested under the real working conditions in respect to the standards.