Characterisation of thermal influences after laser processing polycrystalline diamond composites using long to ultrashort pulse durations

• ps-, ns- and μs-pulsed laser processing of PCD composite cutting tools.
• Raman spectroscopy of clearance face before and after laser processing.
• Cross section at the clearance face generated using focussed ion beam techniques.
• Cross section used to measure and analyse graphitic carbon layers and HAZ.
• Graphitisation mechanisms due to thermal influences are presented.

The laser processing of cutting tool edges is growing rapidly due to its flexibility, short cycle times and negligible waste. However, the quality of the tool and its cutting edge can vary greatly with different laser parameters and processing strategies. The generation of a graphitic carbon layer and a heat affected zone (HAZ) could occur during laser processing which is expected to reduce the quality and lifetime of the cutting tool. By using focussed ion beam (FIB) techniques to generate a cross section, the graphitic carbon layer and heat affected zone are characterised quantitatively and qualitatively for laser processes and as a reference, lapping and wire electro-discharge machining processes, used in the generation of polycrystalline diamond composite cutting tool edges. A focus is put on laser based techniques which vary in pulse duration from long microsecond pulses down to ultrashort picosecond pulses. A deep insight into the focussed ion beam techniques used and extensive analysis through Raman spectroscopy and energy dispersive X-ray spectroscopy (EDX) into the laser–material interactions are presented.

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