Cryogenic assistance during CFRP drilling

Abstract

The CFRP cutting mechanisms are highly linked to fibers orientations. Firstly, this paper deals with a mechanical characterization of CFRP under cryogenic temperatures. An instrumented compressive test with fibers oriented at 45° regarding the crushing direction has been conducted ranging from -196°C to 20°C to follow the evolution of the failure stress of the epoxide resin. Secondly, a semi-orthogonal radial turning experiment on unidirectional CFRP (T800M21 UD) disc with and without cryogenic assistance has been performed. As the fibers are oriented perpendicular to the spinning axis, on one turn, the tool cuts all the fibers with angles varying from 0° to 360°. During these specific tests the cutting forces have been monitored to characterize the cutting forces evolution versus fiber orientation. The experiment showed that cryogenic machining increases cutting forces but decreases surface roughness compare to dry machining.