RECOGNITION OF WOOD CUTTING CONDITIONS TH ROUGH CUTTING SOUNDS III - CORRESPONDENCE BETWEEN BREAKING SOUNDS IN WOOD BREAKING TESTS AND CUTTING SOUNDS IN SEVERAL TYPES OF CHIP FORMATIONS

The purpose of this study was to clarify the effects of wood breaking sounds on the cutting sounds in the ultrasound frequency range (20 k-1 00 kHz). The wood breaking tests simplifying the process of chip forma tions were made to examine the frequency characteristics of breaking s ounds in splitting, bending, and shearing. The orthogonal cutting test s also were made to examine the frequency characteristic of cutting so unds in the five types of chip formations (flow, split, compressive, s hear, and tear). The correspondence between the above-mentioned two fr equency characteristics in the ultrasound frequency range was investig ated. The results were as follows: 1) The frequency characteristics of the breaking sounds in both bending and splitting showed a constant s ound pressure level in the frequency range of 40 kHz to 100 kHz. Howev er, the sound pressure level of the breaking sound in bending was high er than that oi the breaking sound in splitting. 2) The frequency char acteristic of the breaking sound in shearing showed a decreasing of so und pressure level with increasing frequency, and this breaking sound included few components of frequencies above 80 kHz. 3) In the ultraso und frequency range, the frequency characteristics of the cutting soun ds correspond well with the breaking sounds of the main breaking types for each of the chip types. Consequently, it was clear that the wood breaking sound affects considerably the cutting sound of the ultrasoun d frequency range generated during chip formation.