Responsive Fixture Design Of Large-Scale Aerospace Patrs

Associating with the National Science and Technology Key Project, the National Natural Science Fund Project, and requirements from aviation manufacturing industry, a responsive fixture is desigend for the precision machining of large-scale aerospace parts to address the issue of machining distortion due to the thin-walls and high mater ial removal rates. The part location and orientation can be adjusted timely to ensure follow-up operations are carried out under low stress. The main achievements of this paper are presented as follows:(1)An industry survey about the requirement of clamping device in the NC machining was carried out. The results showed that large number of structual parts in airplanes many have thin-walls, are large in size and conplex in shape. While fixture can be a big factor affecting understanding machining deformation. The existing traditional clamp method of aircraft structural parts may not meet the requirement of machining quality due to large deformation, which brings forward a impending need for fixture.(2) An responsive fixture that would automatically respond to workpiece deformation during machining is designed. The design methods of mainly function modules are introduced. A practical design example and check of key parameters are given out by using a typical aircraft structural part. It settles base for adaptive machining.(3) The control method of responsive fixture is proposed. The methods for condition monitoring of part machining, deformation releas ing, deformation monitor ing and clamping mechanism controlling are introduced. That realizes the real-t ime transport of monitor signal, clamping and adjusting of fixture, as well as the deformation release.(4) At last, experimental validation of this fixture is undergone. A supporting software is developed for the adaptive machining of aircraft structural parts, and the practicability of the system is proved. The experiment results show that, the responsive fixture designed in this article can reduce the machining deformation, improve the qualified rate.