Study of the effect of PCM process parameters on geometry type, Ra, depth of etch, undercut comparing FeCl3 and CuCl2 etchants on Monel 400

The study mainly focuses on geometrical topographies in photochemical machining (PCM) of Monel 400, using two etchants cupric chloride (CuCl2) and ferric chloride (FeCl3). The experiments were carried out at different etchant concentrations (including a number of chloride ions and weight) and temperatures. A comparative study was carried out on the responses such as depth of etch, undercut, surface roughness (Ra), and geometrical features, viz. etch factor and aspect ratio. This study also implicates the effects of perimeter and geometry type (circle, hexagon, square, rectangle, and triangle) on behaviour of PCM process in the perspective of loss of weight and depth of etching, wherein triangular shape shows 0.1547 µm depth of etching/min and 0.0737 g/min weight loss. The results show that FeCl3 gives 0.8 µm Ra and 13.59 µm/min etch rate with 0.851 etch factor at 80℃ compared to CuCl2. The overall conclusion shows that FeCl3 performs better than CuCl2 in the aspects of PCM for Monel 400.