International Conference on Advance Mechanical Engineering (ICAME09), 22~25Jun, Concorde Hotel, Shah Alam, Selangor, 2009. Drilling on Fibre-Glass Composite using CO 2 Laser M.M.Noor, T.T.Mon, K.Kadirgama, M.R.M.Rejab, M.S.M.Sani, R.Rafizuan, W.A.W.Yusof Faculty of Mechanical Engineering Universiti Malaysia Pahang, 26300 UMP, Kuantan, Pahang, Malaysia Phone: +609-5492223 Fax: +609-5492244 E-mail: muhamad@ump.edu.my / montt@ump.edu.my Abstract Fibre-glass composite has been increasingly used in automotive, aerospace and electronics industries, where hole making on this material is a major process. In this paper, non-traditional machining method was employed to drill the fibre-glass composite sheet of 2 mm in thickness having four layers of glass-fibre with orientation <0, 90, 0, 90>. The machining setup consists of computer-controlled laser source and air supply by a compressor that acts as assist gas for cooling. The type of laser source was CO 2 with a maximum power of 30W. The machining parameters under consideration were laser power and pulse duration. A total of 12 holes were drilled varying laser power and pulse duration. Laser power was varied from 15 to 25W while pulse duration from 2 to 5 minute. Laser-drilled holes were investigated under optical microscope. The hole quality was evaluated with the hole size, hole geometry, burn mark and heat-affected zone. Hole quality were then compared for each parameter combination. It was found that the laser power had predominantly affected the quality of the hole in fibre-glass composite material during laser-drilling. Keywords: laser-drilling, CO 2 laser, fibre-glass composite, heat-affected zone Introduction Manufacturing process nowadays demands advanced machining techniques to fulfil the stricter design requirements and to machine difficult-to-machine materials such as tough super alloys, ceramics, and composites. Traditional machining processes also tend to be obsolete when dealing with advanced design and materials. As a result, manufacturers and machine design engineers are turning to advance machining processes. One of the most-useful advanced processes is laser machining where modified light energy is used to fabricate any geometry on difficult-to-machined materials. Particularly, hole making by laser or laser drilling of composites is one major process that may be found in automotive, aerospace and electronic industries [1]-[9]. Basically, there are two common techniques used in laser drilling: percussion and trepanning. Percussion drilling is a process where multiple pulses are applied per hole to achieve the desired results. Trepanning is a process by cutting large holes or contouring shaped holes. The one that interests the authors in this research is the percussion hole drilling on glass-fibre composite as this material has been increasingly used in above-mentioned industries [2], [4], [8], [10], [11]. Looking back at the past study, unfortunately only limited work on laser drilling have been reported. Their research were mainly focus on indentifying possible parametric optimization in laser drilling, modelling the laser drilling mechanism and studying the effect of laser drilling on different types of materials. The materials tested are mostly metals. The process parameters considered were laser pulse width, pulse energy, beam intensity, and material thickness. Based on quantitative and qualitative analysis method, the hole quality was identified in term of barrelling size, re-solidified material, surface debris, inlet cone, exit cone, and mean hole diameter. From the parametric study in laser drilling of stainless steel, nickel and titanium, it was stated that the material thickness were the most significant parameter that affect the quality of hole [12]-[17]. One remarkable research on laser drilling of composite was conducted by [6] whose focus was laser drilling of carbon-fibre composite. It was reported that common defects occurred in laser drilling of such composite were overheating, fibre swelling and large affected zone. The substantial fibre swelling observed around laser-drilled holes was associated with rapid volatilization of impurities within the fibre occurring simultaneously with the structural reordering expected when high temperatures (1300–2000°C) were attained. The objectives of this research are to experimentally analyze the effect of laser parameters on drilling of fibre- glass composite and to investigate the quality of hole associated with the laser parameters under consideration.