Hole Quality and Damage in Drilling Carbon/Epoxy Composites by Electrical Discharge Machining

This study investigates the material removal mechanisms and machining damage in drilling of carbon fiber epoxy composite by electrical discharge machining (EDM). Detailed investigation of the morphology of the machined surfaces and elemental analysis were conducted inside a scanning electron microscope. Machining damage was characterized by the extent of delamination, hole taper, and the average width of the heat-affected zone (HAZ). The effect of pulse-on time and gap current on machining damage was also investigated. It was found that material removal occurred mainly in the form of decomposition of the polymer matrix and thermally induced fracture of the carbon fibers. Vaporization of the carbon fibers due to spark and Joule heating is also a possible mechanism. The width of HAZ was found to be influenced the most by pulse-on time where the minimum HAZ occurred for intermediate pulse-on time. Furthermore, the width of HAZ and hole taper in EDM were found to be comparable to or less than those obtained by laser cutting.

[1]  Juan Pou,et al.  Experimental study on the CO2 laser cutting of carbon fiber reinforced plastic composite , 2012 .

[2]  Ws S. Lau,et al.  Electrical discharge machining of carbon fibre composite materials , 1990 .

[3]  Michael F. Zaeh,et al.  Laser Cutting of Carbon Fiber Fabrics , 2013 .

[4]  A. Nagpal,et al.  Synthesis and Characterization of Phenoxy Modified Epoxy Blends , 2010 .

[5]  C. Emmelmann,et al.  Influence of laser cutting parameters on CFRP part quality , 2010 .

[6]  Islam Shyha,et al.  An Investigation into CO2 Laser Trimming of CFRP and GFRP Composites , 2013 .

[7]  Hatim Haloui,et al.  Laser ablation of CFRP using picosecond laser pulses at different wavelengths from UV to IR , 2011 .

[8]  Takeo Tamura,et al.  Measurement of impulsive forces and crater formation in impulse discharge , 2004 .

[9]  Valentina Lopresto,et al.  Solid state Nd:YAG laser cutting of CFRP sheet: influence of process parameters on kerf geometry and HAZ , 2009 .

[10]  Uwe Teicher,et al.  Micro-EDM of Carbon Fibre-Reinforced Plastics , 2013 .

[11]  Frank Schneider,et al.  High Power Laser Cutting of Fiber Reinforced Thermoplastic Polymers with cw- and Pulsed Lasers☆ , 2013 .

[12]  Akira Okada,et al.  Effect of cutting direction on machining of carbon fibre reinforced plastic by electrical discharge machining process , 2013 .

[13]  Masanori Kunieda,et al.  Temperature Distribution Measurement in EDM Arc Plasma Using Spectroscopy , 2004 .

[14]  S. Y. Liu,et al.  Effect of electrical discharge machining on the characteristics of carbon fiber reinforced carbon composites , 2001 .

[15]  H. Hocheng,et al.  The Feasibility Analysis of Electrical-Discharge Machining of Carbon-Carbon Composites , 1998 .

[16]  P. M. George,et al.  EDM machining of carbon–carbon composite—a Taguchi approach , 2004 .

[17]  Oliver Meier,et al.  Investigations on the thermal effect caused by laser cutting with respect to static strength of CFRP , 2008 .