101 Dynamic behavior of polycarbonate sheet for machine tool safety guarding

Abstract

High spee[1 machining eonsists to use high spood fbod rates and high ttequencies of rotation in order to chtain a best finish surface integhty includmg geometric aecuracy, surfhce roughtiess but also lower residunl strcsses. We arc meanly interested by high spoed milling. This tec hnique is in constant development but the sttfety in the workng environment seams to be not realy stedied. For examp!e, if we assume a too1 breakage by using an electro-spindle with the foliowing characteristics:rnaxiinurn rotation speed of 45ooO rpm, maxirrium power of cut of 40 kW, and maximum too1 diameter of 50 um the prejectile is ejocted with a velocity of 235 m.s'i. Also it is necessary to detme thc good choice for gtazing in operator windcvws. An cxperimental investigation to assess the effbet of projeetile shape and velocity on the impact response ofthin polycarbonate target plates was performed. Deformation and failure phenomena were observed and discussed.Kay IYbtzls/ Qynamic.fi'acture. H}'gh speed machining, Polycarbonate