In-situ cutting temperature and machining force measurements during conventional drilling of carbon fiber polymer composite laminates

Abstract

The evolution of in-situ cutting temperature and machining forces during conventional drilling of multi-directional carbon fiber reinforced polymer (MD-CFRP) laminates using a novel inverted drilling setup is presented. The in-situ cutting temperature was measured using fiber Bragg grating (FBG) optical sensor embedded in the stationary drill. The effect of machining parameters such as spindle speed and feed rate on the temperatures and machining forces were studied that indicate the predominant effect of spindle speed on machining temperatures. The drilled MD-CFRP samples and drill bits were characterized by scanning electron microscopy (SEM) and micro-computed tomography ([Formula: see text]) techniques to assess machining-induced damage in the samples and tool wear in the drill bits. Exit-ply delamination was observed in MD-CFRP samples that aggravates with increase in cutting temperature and thrust force caused by evolving tool wear. The measured in-situ machining temperatures using the current experimental setup can be used to achieve better machining models.

Temperature field evolution and thermal-mechanical interaction induced damage in drilling of thermoplastic CF/PEKK – A comparative study with thermoset CF/epoxy

“…To address the above concern, Sorrentino et al [23] measured the CF/epoxy drilling temperature with K type thermocouples and found that the maximum temperature increases with the cutting speed and decreases with the feed rate. Kubher et al [24] embedded a fibre Bragg grating optical sensor into the drill bit and the temperature rise due to tool wear was captured next to the machining zone. Fu et al [2] deployed high resolution infrared thermography to investigate the drilling temperature of unidirectional and multidirectional CF/epoxy.…”

Characterization of cure residual strain development and associated structural distortion in carbon fiber polymer matrix composites

“…This difference in cure strain magnitudes can be attributed to the inherent anisotropy; CTE of C-fiber, along the fiber direction, is almost zero or negative, while CTE in the transverse direction is very large. [43][44][45][46] In case of C-fiber IM7, longitudinal CTE is À0.4 × 10 À6 / o C and transverse CTE is 5.6 × 10 À6 / o C. 44 Thus, in the case of UD-CFRP laminate, the laminate shrinks across the fiber direction larger than along the fiber direction. Additionally, inhomogeneity due to the presence of epoxy and C-fiber results in residual strain in the epoxy phase due to constraining effect offered by the surrounding C-fiber preform.…”

On the Machining Temperature and Hole Quality of CFRP Laminates When Using Diamond-Coated Special Drills

“…Moreover, the surface defects residing within the composite hole cut by the step drill mainly include surface cavities due to the loss of matrix, resin smearing, and fiber pullout voids, as shown in Figure 10. Note that the previous research carried out by Kubher et al [36] addressed the evolution of in-situ cutting temperature and machining forces during the conventional drilling of MD CFRP laminates. Similar surface defects, including resin smearing and bending-induced fracture of carbon fibers, could be found in the research.…”

“…A critical review conducted by Ismail et al [34] offered a clear understanding of the current advances in drilling composite materials, which focused on the aspects of tool geometries, materials, and parametric designs. Fu et al [35] and Kubher et al [36] investigated the temperature characteristics in drilling unidirectional (UD) and multidirectional (MD) CFRPs. Due to the associated temperature effects, utilizing MD CFRPs could result in more difficulties in achieving high drilling qualities than UD CFRPs at certain fiber cutting angles.…”