A Study on Drilling High-Strength CFRP Laminates: Frictional Heat and Cutting Temperature

Abstract

High-strength carbon fiber reinforced polymer (CFRP) composites have become popular materials to be utilized in the aerospace and automotive industries, due to their unique and superior mechanical properties. An understanding of cutting temperatures is rather important when dealing with high-strength CFRPs, since machining defects are likely to occur because of high temperatures (especially in the semi-closed drilling process). The friction behavior at the flank tool-workpiece interface when drilling CFRPs plays a vital role in the heat generation, which still remains poorly understood. The aim of this paper is to address the friction-induced heat based on two specially-designed tribometers to simulate different sliding velocities, similar to those occurring along the flank tool-work interface in drilling. The elastic recovery effect during the drilling process was considered during the tribo-drilling experiments. The drilling temperatures were calculated by the analytical model and verified by the in-situ experimental results gained using the embedded thermocouples into the drills. The results indicate that the magnitudes of the interfacial friction coefficients between the cemented carbide tool and the CFRP specimen are within the range between 0.135–0.168 under the examined conditions. Additionally, the friction caused by the plastic deformation and elastic recovery effects plays a dominant role when the sliding velocity increases. The findings in this paper point out the impact of the friction-induced heat and cutting parameters on the overall drilling temperature.

Effects of Nano Organoclay and Wax on the Machining Temperature and Mechanical Properties of Carbon Fiber Reinforced Plastics (CFRP)

“…Temperatures increase linearly with normal forces. This result allows confirmation of the hypothesis that heat is mainly produced by friction, which is commonly assumed in CFRP machining [7,8]. This also helps to understand how temperatures are decreased.…”

“…Temperature rising is generally explained by friction, especially the kind occurring at the tool/workpiece interface on the tool clearance face. Considering the powdery chips, friction at the chip/tool interface is also negligible [7,8]. Even if the temperatures obtained are low, comparatively to metals, matrix glass transition temperature is often exceeded, and thermal damages may be caused on the surface [9].…”

Experimental investigation on micromachining of epoxy/graphene nano platelet nanocomposites

“…The experimental results can then be used to guide production and material design. Xu et al [31] had investigated the machinability of CFRP composites using drilling method, and the studies provide good examples for this study.…”

Experimental Study of Drilling Temperature, Geometrical Errors and Thermal Expansion of Drill on Hole Accuracy When Drilling CFRP/Ti Alloy Stacks

“…Taking into consideration the measurement of the drilling temperature ( Figure 4 b) and the related discussion, it becomes more evident that the distribution of heat in CFRP reduces the adhesion connections between the fiber and epoxy. In research focused on studying frictional heat and cutting temperature of CFRP [ 48 ] as well as in the study of temperature-dependent properties of CFRP, the phenomenon of decreasing of interfacial shear strength and fracture toughness was reported [ 38 ]. In Reference [ 22 ] it was described as the indirect connection of drilling temperature and residual stress under the machined surface of the CFRP/Ti alloy.…”