Fixtures are necessary to hold a workpiece stable and aligned during a machining process. From this point of view fixtures are, among the machine tool and the tool, one of the main influencing factors on the machining quality and the processing time in manufacturing. Because of the large amount of different workpieces and machining tasks a lot of different applications exist.
Machining structural parts in aerospace industry is usually based on a massive block or a plate of raw material. A large proportion of material (up to 90%) is removed into chips. Depending on the residual stress field of the workpiece after the unclamping the fixture a distortion of the workpiece will appear. This leads to a higher number of machining steps and a more time consuming machining process.
The objective is the development of fixture components and a method for clamping structural part in a way that the distortions of the workpieces are minimised. A residual stress and distortion model will predict the behaviour of the workpiece. The prediction of this model will be the inputs for intelligent fixtures. An intelligent fixture system is able to apply a displacement of the stock in opposite direction to the expected distortion.
