Building and preliminary evaluation of a demonstrator fixture system for milling aircraft components

Important results from the project

The purpose of the project is to manufacture and verify a demonstrator of a light milling fixture for machining of aircraft parts. With an existing milling fixture in Saabs workshop as model, a corresponding composite fixture was made. These two fixtures have been compared to each other and the composite fixture has showed fully corresponding characteristics and thereby fulfil the project goal.

Expected long term effects

The composite fixture show, even though it is 75% lighter, as good characteristics when it comes to stiffness, eigenmodes and damping. When comparing the same machine part manufactured in each fixture, the composite fixture produces as good or better quality parts. Also, the machine operator favors the lighter fixture, making rigging easier and safer. A reduced mass to transport during the machining operation (the whole fixture moves continuously in these machines) can be used for higher feeds and faster transports. Otherwise the weight reduction will lead to lower machine wear.

Approach and implementation

During a previous study a composite fixture design has been developed. Within this project a fixture has been produced by Flexprop (now Composite Services Europe AB). The fixture has been tested at Saab’s machine shop. An existing machine part in current production has been chosen to be manufactured in each fixture, thereafter the quality of the parts has been compared. The fixtures have also been evaluated by measuring eigenmodes in different directions.