Influence of design parameters on the penetration resistance of machine guards

Abstract

In the last years, different research on ballistic penetration of machine tools guards, as defined in EU Directive 2006/42/EC, were conducted in different worldwide laboratories. Even if the design of machine safety guards using the material/thickness are defined in annexes of ISO standardization, a revision of those annexes is expected in next years. Standardized tests have some limitations because they are performed using a given penetrator that impacts perpendicularly the surface of flat plates of about 500 mm x 500 mm. In this paper the influence of some design parameters will be investigated by polycarbonate sheets of 4mm thickness. The evaluation of ballistic limit for 4 mm sheets of 300 mm x 300 mm and 500 mm x 500 mm size will be presented. Moreover, the influence of constraint on ballistic limit of standardized 500 mm x 500 mm sheets will be also presented by two different constraint devices: one similar to a border hinge constraint, one to a border rigid clamping. Discussion of results will be presented with a view to review the ISO standardization annexes on ballistic penetration.