Optimization of technological parameters of CNC milling of plywood depending on surface roughness

Attaining optimal milling conditions in industrial applications presents a significant challenge. This paper investigates the influence of feed speed and rotational speed in CNC milling on plywood surface quality. Furthermore, it aims to optimize these parameters to minimize surface roughness and associated defects. The roughness parameters (Ra, Rz, Rp and Rv) were quantified using a Keyence VHX-7000 digital microscope. In addition to surface roughness analysis, delamination of veneers and the origins of surface irregularities were microscopically analysed. The polynomial regression models for Ra and Rz were subsequently developed to identify optimal milling conditions. At rotational speed of 20,000 rpm and at feed speed of 10 m min⁻¹ the lowest roughness was achieved. However, very rough fuzzy surface with kinematic traces of the tool, delaminated veneers and torn fibres had occurred at rotational speed of 12,000 rpm and at feed speed of 18 m min⁻¹. These results were supported by investigating the effect of feed per tooth and chip thickness on surface roughness. The highest coefficient of determination was observed between feed per tooth or chip thickness and Rp parameter. The main outcome of this paper was the identification of the most optimal combinations of technological parameters, considering the overall condition of the plywood surface.