Sequential Laser - Mechanical Drilling of Thick Carbon Fibre Reinforced Polymer Composites (CFRP) for Industrial Applications

Carbon fibre reinforced polymer composites or CFRPs can be costly to manufacture, but they are typically used anywhere a high strength-to-weight ratio and steadiness (rigidity) are needed in many industrial applications, particularly in aerospace. Drilling composites with a laser tends to be a feasible method since one of the composite phases is often a form of polymer, and polymers in general have a very high absorption coefficient for infrared radiation. The feasibility of sequential laser-mechanical drilling of thick CFRP is discussed in this article. 1 kW fibre laser is chosen as a pre-drilling or initial stage and mechanical drilling is the final step. The sequential drilling method dropped the overall thrust and torque by an average of 61%, which greatly increased the productivity and reduced the mechanical stress on the cutting tool while also increasing the life of the bit. The sequential drilling (i.e. laser 8mm and mechanical 8mm) for both drill bits (i.e. 2- and 3-flute uncoated tungsten carbide) and laser pre-drilling techniques has demonstrated the highest delamination factor (SFDSR) ratio. A new laser-mechanical sequence drilling technique is thus established, assessed and tested when thick CFRP composites are drilled.