Experimental Study of the Woodworking Dynamics with End Milling Cutters

Abstract

Efficient operation of modern multifunctional woodworking centers with computer numerical control (CNC) is associated with the creation of rational designs of end milling cutters for multi-axis processing. The research purpose is an experimental study of the dynamic parameters of wood processing with end milling cutters and their influence on the surface roughness depending on the structural elements of the tool. The varying structural elements of the cutters are the cutting edge inclination, the teeth number, the circular pitch irregularity and the presence of chip separation grooves on the cutting edges. A set of experimental milling cutters with various structural elements was used in the research. Cutting experiments were performed under the production conditions with the use of vibration-measuring complex (Bruel & Kjaer). Factorial designs of studies, methods of vibration measurements and processing of vibroacoustic signals are given. The article presents the qualitative assessment of the degree of influence of various structural elements of end milling cutters on the vibractivity of processing pine and oak wood. On average, the vibration level during the processing of oak blanks is higher by 60-75 % in comparison with pine blanks; while the roughness of the treated surface differs only by 10-20 %. A steady correlation between the level of vibrations and the roughness of the treated surface was found. Increasing the cutting edge inclination, the teeth number, as well as the presence of chip separation grooves reduces vibrations and helps to improve the condition of the treated surface for both wood species. The influence of circular tooth pitch irregularity on the studied parameters is ambiguous.