Drilling tool geometry evaluation for reinforced composite laminates

Abstract

In this work, a comparative study on different drill point geometries and feed rate for composite laminates drilling is presented. For this goal, thrust force monitoring during drilling, hole wall roughness measurement and delamination extension assessment after drilling is accomplished. Delamination is evaluated using enhanced radiography combined with a dedicated computational platform that integrates algorithms of image processing and analysis. An experimental procedure was planned and consequences were evaluated. Results show that a cautious combination of the factors involved, like drill tip geometry or feed rate, can promote the reduction of delamination damage.

Drilling optimization of woven CFRP laminates under different tool wear conditions: a multi-objective design of experiments approach

“…The same effect has been observed at the entry of the hole in cross-ply composite materials with twist drill bits (Durão et al 2010). In particular in the latter study, the thrust force was higher for 120°compared to 85°point angle bit, while delamination at the hole entry was lower for the former case (Durão et al 2010). In another study it was observed that with a double-point angle drill bit, the hole diameter tolerance criterion is more critical at elevated feed rates than the exit delamination (Karpat et al 2012).…”

“…Increasing the point angle in conventional drills has also improved the quality of the hole in entry (less delamination), but it worsened the hole quality at the exit (Heisel and Pfeifroth 2012). The same effect has been observed at the entry of the hole in cross-ply composite materials with twist drill bits (Durão et al 2010). In particular in the latter study, the thrust force was higher for 120°compared to 85°point angle bit, while delamination at the hole entry was lower for the former case (Durão et al 2010).…”

Tool geometry based prediction of critical thrust force while drilling carbon fiber reinforced polymers

“…The relationship between process parameters, drill geometry and process outputs has also been studied [6][7][8]. It was shown that feed rate must be kept low in order to keep thrust forces low during drilling to minimize the likelihood of delamination.…”

Minimizing Drilling Thrust Force for HFRP Composite by Optimizing Process Parameters using Combination of ANOVA Approach and S/N Ratios Analysis

“…They concluded that "Brad and Spur" carbide drill with two cutting edges provide the lowest thrust force that is responsible for the least damage on the composite laminate. Durão et al [3] did a comparative study on different drill point geometry and feed rate for drilling carbon fiber reinforced laminates. The used of 120° drill point geometry had produced the minimum delamination factor (Fd) when drilling the composite at higher feed rate.…”

“…The research conduct on [2][3][4][5] were mostly related to drilling the conventional FRP composite materials like glass fiber reinforced polymer (GFRP) composite or carbon fiber reinforced polymer (CFRP) composite using various drill point angle, cutting speed and feed rate. None of them have studied on the drilling of hybrid fiber reinforced polymer (HFRP) composite.…”