Deburring drilled holes in CFRP composites with large pulsed electron beam (LPEB) irradiation

Abstract

The generation of burrs is one of the most common problems affecting carbon fiber reinforced plastic (CFRP) machining processes. However, it is difficult to develop machining processes that generate no burrs. To overcome the limitations of conventional CFRP composite deburring methods, we propose a new process for deburring drilled holes in CFRP composites based on large pulsed electron beam (LPEB) irradiation. We evaluated the deburring performance as we independently varied the three major controllable parameters that affect energy transfer during LPEB irradiation, namely the acceleration voltage, solenoid voltage, and number of pulses. We optimized the irradiation process to improve the accuracy of the shapes of the holes, and reduced the sizes of the burrs by 97%. We evaluated deviations in the shapes of the holes from perfect circles by measuring their diameters. As our deburring process reduced these deviations by 93%, it significantly improved the dimensional accuracy of the holes. We hypothesize that the deburring mechanism starts with evaporation of the resin that coats the carbon fibers evaporates. This leaves the uncut carbon fibers exposed so that they can be detached by the LPEB irradiation. We obtained high quality, burr-free drilled holes by applying the proposed LPEB deburring method.