Comprehensive investigation of cutting mechanisms and hole quality in dry drilling woven aramid fibre–reinforced plastic with typical tools

Abstract

Due to high specific strength and strong toughness, aramid fibre–reinforced plastics have been widely used in the aircraft, military, and automobile industries. However, in the hole-making process, these excellent properties make aramid fibre–reinforced plastics difficult to machine and prone to severe entrance and exit damages. In this article, the cutting mechanisms of three typical tools (twist drill, burr tool, and brad drill) are thoroughly investigated during dry drilling of aramid fibre–reinforced plastic. On this basis, systematic experiments are conducted to evaluate the cutting performance and hole quality. At the hole entrance, the cutting edges of the twist drill peel and tear the uncut material, which results in severe fuzzing damage. Due to the radial rake angles of the burr tool and brad drill, the radial component of the cutting force can pre-tension aramid fibres prior to being cut, which effectively reduces the fuzzing defect. At the hole exit, the extrusion action of the chisel edge and the severe chip adherence are the main causes of exit damage for the twist drill and burr tool, respectively. Due to the decrease in the thrust force and improvement in the shearing action, the best hole quality is achieved by the brad drill. To further improve the hole quality, an auxiliary approach using collars is introduced to effectively restrain the damage by enhancing interfacial bonding strength. This article provides comprehensive and available information on tool performance for drilling aramid fibre–reinforced plastics, which can help guide process optimizations to achieve the desired hole quality.

An analytical delamination model of drilling aramid fiber–reinforced plastics by brad drill

“…The AFRP laminates used in this study are made of plain-woven aramid/epoxy prepregs with 60 vol% fiber fraction. The fabrication of the AFRP laminate follows the preciously established method [30]. More specifically, AFRP laminates were cured in an autoclave at 115°C for 60 min, and then at 180°C for 120 min.…”

“…Dí az-Álvarez [29] compared the cutting performance of a brad drill and a twist drill during drilling of AFRP laminates and found that the brad drill can better suppress the delamination and fuzzing under low feed rates and high cutting speeds. Liu et al, further confirmed that the brad drill can effectively restrain the concession and deformation of aramid fibers and improve the shearing action of the cutting edge [30]. Despite the promising experimental results seen in drilling of AFRP deploying brad drills, the detailed delamination mechanism and the corresponding analytical model associated with such process are still lacking.…”

Reducing delamination risk with response surface methodology-supported drilling analysis for Nomex® aramid fiber composites

“…49 There are also studies in the literature showing that the brad drill produces the best hole quality in AFRP drilling due to the reduction in thrust and improvement in cutting action. 50 Push-out delamination, in contrast, occurs at the bottom surface of the drilled hole in a composite material. As the drill bit nears the hole exit, the thickness of the composite it needs to drill through becomes reduced.…”

Determination of Processing Precision of Hole in Industrial Plastic Materials

“…Similar research is in [2], which approached the problem by conducting systematic experiments to evaluate cutting performance and hole quality. Upon entering the holes, the cutting edges of the twist drill peel and tear the uncut material, resulting in severe fuzzing damage.…”

“…The experimental results indicated that the most significant effect was that the drill type influenced both the delamination factor and the surface roughness. All these articles [ 1 , 2 , 3 , 4 , 5 ] provide comprehensive and available information on the performance of tools for drilling aramid fiber-reinforced plastics, which can help guide process optimizations to achieve the desired hole quality.…”