Designing of an adaptive fixture for thin-walled free-form surfaced parts

Free-form surfaced thin walled parts are generally preferred because of their lightness and strength in aerospace industry. Fixtures are the main elements in manufacturing processes, such as machining, grinding, welding, assembling etc. Pin fixtures are type of fixtures and they are gaining popularity since they can adopt part surface. This study aims to design and investigate the pin fixtures for free-form surfaced thin-walled parts to be machined. In machining of free-form surfaced thin-walled parts, main machining considerations are deflections which directly affect the dimensional tolerances and part qualities, and stresses considered as a main cause of deflection. Deflection results were obtained for three pin diameters, three pin configurations and three different forces at two points using ANSYS FEA software. The Von-Mises stresses were also analyzed for the same principle as used in the deflection analyses. Through determining the best pin fixture configuration and pin diameter, it is aimed to design an adaptive pin fixture for thin-wall machining and blade tip repair without excessive deflections. The results have shown that the array configuration can be used as the best adaptable fixture type for part-to-part geometry. Minimum deflections both for edge and midspan loading are obtained for array configuration using 2mm pin diameters.