Int. J. Materials and Product Technology, Vol. 43, Nos. 1/2/3/4, 2012
43
Copyright © 2012 Inderscience Enterpris Ltd.
Drilling of carbon fibre reinforced plastic (CFRP) composites – a review
I. Paul Theophilus Rajakumar* and P. Hariharan秦玥飞
Department of Manufacturing Engineering, College of Engineering, Anna University,
Guindy, Chennai – 600025, India E-mail: E-mail: hari@annauniv.edu *Corresponding author
L. Vijayaraghavan
Manufacturing Engineering Section, Department of Mechanical Engineering, IIT Madras,
Chennai – 600036, India E-mail: lvijay@iitm.ac.in
Abstract: The principal aim of this work is to prent a review of the literature of the past 30 years on drilling of carbon fibre reinforced plastic composites. This paper focus on the drilling factors influencing the drilling process and the defects which may occur during the drilling of CFRP composite laminates. Aspects such as machining parameters, tool geometry, tool types and materials, tool wear, induced thrust force and torque, the quality of the drilled hole with special attention to the delamination and surface roughness are given detailed consideration in this paper.
Keywords: drilling; carbon fibre reinforced plastic; CFRP; composite; feed; cutting velocity; tool geometry; tool wear; torque; thrust force; delamination; surface roughness; roundness; tiny cracks; pitting; edge chipping.
Reference to this paper should be made as follows: Rajakumar, I.P.T., Hariharan, P. and Vijayaraghavan, L. (2012) ‘Drilling of carbon fibre reinforced plastic (CFRP) composites – a review’, Int. J. Materials and Product Technology , Vol. 43, Nos. 1/2/3/4, pp.43–67.
Biographical notes: I. Paul Theophilus Rajakumar is rearch scholar in the Department of Manufacturing Engineering, College of Engineering, Anna University, Guindy, Chennai, India and also Associate Professor in the Department of Mechanical Engineering, Panimalar Engineering Colle
ge, Chennai, India. He obtained his BE (Mech) from Karunya Institute of Technology, Coimbatore, India and ME (CAD) from Sathyabama University, Chennai, India. He is currently doing his rearch in the field of monitoring the machining of composites using acoustic emission technique in the Department of Manufacturing Engineering, College of Engineering, Anna University, Chennai.
44 I.P.T. Rajakumar et al.
育儿问答
P. Hariharan is an Associate Professor in the Department of Manufacturing
Engineering, College of Engineering Guindy, Anna University, Chennai, India.
He obtained his BE (Mech) and ME (Prodn) from College of Engineering
Guindy, Anna University, Chennai, India and PhD in the area of material
processing from Anna University, Chennai. His areas of interest include
micromachining, computer aided manufacturing, robotics, MEMS, electronics
packaging, composites and nano-materials. He has three publications in leading
journals and 50 conference publications.
L. Vijayaraghavan is a Professor in the Department of Mechanical Engineering,
IIT Madras, India. He obtained his BE (Mech) from Annamalai University,
Msc (Engg) in Machine Tool Engineering from PSG College of Technology,
Coimbatore, India, and PhD in the area of metal cutting from IIT Madras,
活板文言文翻译
India. He has rich experience in the areas of metal cutting, nsors for
intelligent manufacturing, machine tool dynamics and kinematics, condition
大家好英文monitoring and CAD/CAM. He has guided 13 PhD (four ongoing) and ven
MS (rearch) scholars. He has 70 publications in leading referred international
journals and 105 conference publications.
1 Introduction
Polymeric composite materials have found greater applications over the last decade, especially the u of carbon fibre reinforced plastic (CFRP) in the aerospace industries has incread considerably. Being one of the advanced materials, the specific modulus and specific strength of CFRP composite are superior to that of the conventional materials as given in Table 1. Therefore, CFRP has found greater application as a structural material.
豆瓣鱼的川味做法Table 1Properties of carbon fibre epoxy composites with fibre volume fraction of 50%
Tensile modulus (E) (GPa) Tensile strength
(σ) (GPa)
Density
(ρ) (g/cm3)
Specific
modulus (E/ρ)
Specific
strength (σ/ρ)
Ultimate
elongation (%)
70 0.6
1.6
43.75
0.375
0.85
Source: Azom (2011)
Machining of CFRP composite materials is an important and current topic in modern rearches on manufacturing process (Sardinas et al., 2006). Drilling is the most frequently employed machining operation for fibre reinforced materials owing to the
need for joining structures. Drilling of CFRP is difficult to carry out due to the anisotropic, non-homogeneous and high abrasiveness of their reinforcing carbon fibres.
In aircraft industry poor hole quality accounts for an estimated 60% of all part rejection (Hocheng and Tsao, 2006). The increasing popularity of carbon composites in industry
and the constant need to maximi productivity has led rearches to look at methods of optimising the drilling process. Therefore, this paper aims to prent a review on the
various rearch trends taking place in the area of drilling CFRP and the areas discusd
are shown in Figure 1.
Drilling of carbon fibre reinforced plastic (CFRP) composites
45
Figure 1
Major areas of rearch in drilling CFRP composites
1.1 Mechanism of drilling
The mechanism of drilling the polymeric composite laminates can be understood easily by analysing the generation of the thrust force during drilling. The generation of thrust force can be divided into three phas such as increasing pha, constant pha and finally decreasing pha. During the increasing pha, sharp increa in thrust force is due to the punching action of the drill as its chil edge gets engaged with the top ply of the laminate as shown in Figure2.
Possible problems that might ari during this stage are skidding, wandering, or deflecting of the drill bit and all of this affect the positioning of the hole. This is followed by a steady increa in the force at a slower rate as the cutting lips enters the work piece. In the constant pha the thrust force remains at an almost constant value as the drill sinks into the work piece. The maximum force occurs during this pha. At the end of this pha the tip of the tool breaks through the bottom ply of the laminate. The risk of delamination is very high during this stage due to the high values of thrust force and torque as the last plies of the laminate are pushed by the chil edge. Finally in the decreasing pha a sharp reduction of the thrust force takes place due to the fact that the tip of the tool has broken through the back face of the work piece and the chil edge has come out of the laminate. When the drill exits the work piece, the thrust force drops to zero or sometimes to a negati
ve value as reaming takes place (Fernandes and Cook, 2006; Davim, 2008; Teti, 2002).
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I.P.T. Rajakumar et al.
小鸡卡通Figure 2
Mechanism of generation of thrust force as a function of drilling time
2 Drilling factors
The factors such as cutting parameters, tool geometries, tool materials, thrust force and torque greatly influence the drilling of CFRP laminates and quality of the drilled hole.
2.1 Cutting parameters
The cutting parameters such as cutting velocity and feed rate have greater effect on the drilling of CFRP laminates.
2.1.1 Effect of cutting velocity
滚球游戏The cutting velocity (m/min) has a greater influence on the thrust force, torque, delamination, power, and specific cutting pressure while drilling the CFRP composite laminates. When cutting speed increas the thrust force decreas as shown in Figure 3. Hence it is better to u higher speeds in drilling CFRP laminates (Jin et al., 2008; Malhotra, 1990; Sardinas et al., 2006; Tsao and Hocheng, 2
007a; Tsao, 2008a, 2008c). Delamination factor both at entrance and exit increas with increa in cutting speed (Davim and Reis, 2003a; Davim et al., 2007).
A combination of lower feed rate and lower point angle with higher cutting speed is suitable in order to reduce delamination damage. This result can be explained by the fact that as the cutting speed is incread, the cutting edge action is reduced for the number of pass across the same region. Also, the friction between cutting edges and the laminates will cau temperature elevation and the softening of the matrix pha, thus reducing damage (Gaitonde et al., 2008).
Drilling of carbon fibre reinforced plastic (CFRP) composites 47 Figure 3
Effect of cutting speed on thrust force (e online version for colours)
手鞠本子2.1.2 Effect of feed rate
In drilling the CFRP composite laminates, the feed rate influences the thrust force, torque, delamination, power, and specific cutting pressure. Lower the feed rate, smaller the delamination and higher the feed rate, larger the delamination. Therefore, low feed is recommended for producing delamination free holes (Enemuoh et al., 2001; Davim and Reis, 2003a; Davim et al., 2007; Seif et al., 2007; Tsao and Hocheng, 2007a, 2007b; Zhang et al., 2003). A low feed rate can also cau delamination becau the cutting time at the same place is too long. A reduction in feed rate rais drill temperature and the
