Demands on the Safety Window

The window must fulfill the following conditions to be resistant to the dangers caused by the high speeds, the mass of the chuck jaws and the very hot chips: High retaining capacity, high resistance to small hot chips and breaking resistance. Penetration of the material must be avoided. According to the current level of knowledge, polycarbonate is the only material that is capable of reliably retaining a chuck jaw that is going to be ejected from the machine, if transparency and a reduction of weight to an adequate level are required.
The resistance of polycarbonate panes to chemicals, however, is very low. It is not resistant to coolants or adhesives. It neither is able to resist mechanical influences such as heat or impacts of metallic parts. The glass pane, which is placed in front of the polycarbonate pane, has turned out to be resistant to chips and coolants and can be used for the protection of the polycarbonate pane.