Experimental Study and Artificial Neural Network Simulation of Cutting Forces and Delamination Analysis in GFRP...

This paper reports the results of measurements of cutting forces and delamination in drilling of Glass-Fiber-Reinforced Polymer (GFRP) composites. Four different types of GFRP composites were tested, made by a different manufacturing method and had a different fiber type, weight fraction (wf) ratio, number of layers, but the same stacking sequence. GFRP samples were made using two technologies: a novel method based on the use of a specially designed pressing device and hand lay-up and vacuum bag technology process. The study was conducted with variable technological parameters: cutting speed v_c and feed per tooth f_z. The two-edge carbide diamond-coated drill produced by Seco Company was used in the experiments. Cutting-force components and delamination factor were measured in the experiments, and photos of the holes were taken to determine the delamination. In addition, modeling of cause-and-effect relationships between the technological drilling parameters v_c and f_z was simulated with the use of artificial neural network modeling. For all tested GFRP materials, an increase in f_z led to an increase in the amplitude of cutting-force component F_z. The lowest values of the amplitude of cutting-force component F_z were obtained with the lowest tested feed per tooth value of 0.04 mm/tooth for all tested materials. It was observed that materials produced with the use of the specially designed pressing device were characterized by lower values of the cutting-force component F_z. It was also found that the delamination factor increased with an increase in f_z for all tested GFRP materials. A comparison of the lowest and the highest values of f_z revealed that the lowest delamination factor increase was archived by the B1 material and amounted to about 12.5%. The error margin of the obtained numerical modeling results does not exceed 15%, so it can be concluded that artificial neural networks are a suitable tool for modeling cutting force amplitudes as a function of v_c and f_z. The study has shown that the use of the special pressing device during the manufacturing of composite materials has a positive effect on delamination.