Comparative assessment of the laser induced plasma micromachining and the micro-EDM processes

Micro-electro-discharge machining (micro-EDM) is a well-established micromanufacturing process and has been at the center of research for the last few decades. However, it has its own limitations. The limitations are primarily due to the requirement of a tool and electric potential between the tool and the workpiece. The laser induced plasma micromachining (LIP-MM) is a novel tool-less multimaterial selective material removal type of micromachining process. In a manner similar to micro-EDM, it also removes material through plasma-matter interaction. However, instead of a tool and electric potential, it uses an ultra-short laser beam to generate plasma within a transparent dielectric media and thus circumvents some of the limitations associated with micro-EDM. The paper presents an experimental investigation on the comparative assessment of the capabilities of the two processes in the machining of microchannels in stainless steel. For comparative assessment of their processing capabilities, microchannels were machined by the two processes at similar pulse energy levels, while other process parameters were maintained at their optimal values for their respective process technology requirements. The comparative assessment was based on the geometric characteristics, material removal rate (MRR), effect of tool wear, and the range of machinable materials.