The effect of the technological and construction parameters of a milling tool for cutting across the grain (0° - 90°) was studied. Air - dried beech was cut, whereby the orientation of the material (0°, 30°, 60° and 90°), the tool rake angle (10°, 20°, 30°, 40° and 50°), as well as the thickness of the chip (0,05 mm, 0,10 mm and 0,15 mm) were altered. For each combination two cuts were made and then the profile of the new surface was measured. Using the profile measured, the parameters for evaluating the roughness of the surface: Ra - the arithmetic mean roughness, Rz - the mean depth of roughness, Rq - standard deviation, Rsk - skewness, Rku - kurtosis and Abbot - Firestone curve parameter were calculated. In the study was found that the best surface quality when cutting across the grain is achieved at 40°, the smallest chip thickness and material orientation at 90°, which corresponds to the radial surface. Therefore, as the aforementioned study indicates, for cutting wood across the grain (0° - 90°) it is best to use a purpose - built milling tool with larger rake angles than those milling tools that are available on the market (which have an angle of approx. 20°)
|
