SOME FUNDAMENTAL-ASPECTS OF WOOD CHIPPING

To improve chip quality with regard to chip and fiber damage, the mechanisms of chip formation must be better understood. Therefore, an experimental setup which can measure the cutting force in two dimensions in low-speed chipping was developed. The influence of clearance angel, bevel angle and chip length on cutting force, chip thickness:length ratio, and fracture mode was studied. It was discovered that the force component perpendicular to the movement of the knife could be quite high and that the clearance angle had a large effect on the resulting cutting force. The experiments revealed that chip formation is quite complicated, since the variables interacted in an unexpected manner. Thus a factorial experimental design is crucial in any study of wood chipping, because the response to a change in one variable depends on the values of the other variables.