Analys: Bearbetade kontra svetsade konstruktioner
Examensarbete på grundnivå
Maskinteknik 180 p.
Tjärnlund Leppämäki, Joakim
Saab Kockums AB requested an analysis between two production methods. At the start of this work, their constructions were welded, but they were wondering if it could be more beneficial to utilize machining instead. Therefore, a comparison was sought between both methods based on factors such as cost, time, strength, etc. Hopefully, the result of the work would give an indication of what method that should be used for future constructions. The analysed methods were welding and 2D-machining, specifically for a mechanical construction called “frame”. A frame in this context is a board, which is used to mount components on in marine vehicles/ships. Without changing the function of the frame, a new machinable design was created in CATIA V5. This design was afterward compared in Ansys Mechanical to the original design. Finally, a machining simulation was created in Creo Parametric CAM to estimate lead time and cost. The new design was exposed to more tensions for the analysed load, but the 6-kilogram weight reduction that was achieved could be exchanged for strengthening. The machining operations were estimated to be 3 hours compared to the welded time of 4 hours. Meanwhile, the total operation cost for machining was 9.9% more expensive than welding. The result showed that it was not profitable for a change of method to produce a low quantity of frames and that the method was less modifiable and less manageable compared to welding. Eventual counter-arguments could be that the machining gives better structural advantages, better ergonomics, and fewer human faults which could be approved as a valid reason for the increased cost. Because the final cost does not differ to a significant degree, there was a consideration for potential further development to contain an analysis of the preparation time for machining as this had the biggest impact on the total cost, to acquire a definitive conclusion