Effect of chip thickness and tool wear on surface roughness and cutting power during up-milling wood of different density

The aim of this study was to determine the effect of average chip thickness and blade wear on the cutting power consumption and surface quality obtained in up-milling wood of different densities. The surface roughness was investigated using the contact method, recording the roughness parameters Ra and Rz, and the cutting power was determined using a wattmeter. The research was conducted for two variants of blade wear, i.e., sharp and blunt, and three variants of chip thickness (0.10, 0.06, and 0.02 mm). Four wood species with very different densities were tested, i.e., balsa (Ochroma pyramidale (Cav. ex Lam.) Urb.), obeche (Triplochiton scleroxylon K. Schum.), alder (Alnus glutinosa L. Gaertn.) and beech (Fagus sylvatica L.) For the lowest density woods, a better surface quality was found when cutting with a blunt knife compared to a sharp knife, while for the higher density woods (alder and beech) an inverse relationship was observed, i.e., a blunt knife resulted in increased surface roughness. For obeche wood, the surface roughness was dependent on the chip thickness. In addition, for low-density woods (balsa and obeche), no differences in cutting power were shown as a function of blade condition. It was shown that both an increase in wood density and chip thickness resulted in an increase in cutting power.