Effect of Average Uncut Chip Thickness on the Colour of Beech Wood (Fagus sylvatica L.) During the Face Milling Process

Abstract

This study aimed to establish quantitative relationships between the average uncut chip thickness and the colour change of beech wood (Fagus sylvatica L.) during face milling. A comprehensive analysis of colour change was conducted based on measurements of chromaticity parameters, lightness, total colour difference, and hue angle variation. It was concluded that the average uncut chip thickness was a key factor in determining the surface’s visual quality. It was found that an increase in average uncut chip thickness (0.13 to 0.38 mm) correlated with a decrease in total colour difference and an increase in lightness, bringing the machined surface’s colour closer to the original wood. This effect was attributed to the minimisation of local thermal effects through optimizing the cutting process. This avoids thermally sensitive chemical reactions that cause colour changes. Results from various statistical analyses showed significant differences in total colour differences across average uncut chip thicknesses of 0.13, 0.25, and 0.38 mm.