High-efficiency and high-quality CFRP machining strategies

Abstract

Due to their outstanding mechanical properties at extraordinary low weight carbon fibre reinforced plastics (CFRP) are going to become a preferred material for high performance structural elements in airplanes, machine tools and cars. Drilling of CFRP is often required process for preparing composite parts for joining and assembling and represents one of the most important machining operations carried out on composites. First experimental results in laser processing show no typical drawbacks for the conventional drilling like tool wear, strong environmental impact caused by noise, delamination and damage of epoxy matrix due to mechanical load as well. The thermal management for the strong anisotropic thermo-physical properties of CFRP with the highly temperature sensitive epoxy matrix remains a big challenge for laser processing. In this paper we show an advanced method for producing high-quality cylindrical through-holes in 2 mm CFRP sheets using picosecond laser pulses. Process strategies are applied as well for heat input control as for achieving highest process efficiency. The picosecond pulse machining will be compared to the results achieved by nanosecond pulses and long microsecond pulses.