ACOUSTIC-EMISSION CHARACTERISTICS IN WOOD SANDING .1. EFFECTS OF THE GRAIN SIZES AND THE SANDING TIMES ON ACOUSTIC-EMISSION IN BELT SANDING

The monitoring technique of the wood machining process is important fo r the automation of wood machining operations, Therefore, the developm ent of a sensing system for the wood machining process has been requir ed. Acoustic emission (AE) refers to the elastic stress waves generate d by the sudden release of energy in deforming or fracturing materials . Therefore, the wood machining processes such as cutting and sanding all generate acoustic emissions. Thus, although fundamental data on th e AE generated in the wood cutting process have been accumulated gradu ally, few investigations on the AE in the wood sanding process have be en conducted. In this study, the AE signals generated during wood sand ing with a belt sander were measured, and the relationship to the stoc k removal rate was examined. The results are summarized as follows: (1 ) The AE signal in wood sanding has a high-frequency component in the range of 0.1-0.3 MHz. (2) The AE count rates increase with increasing grain size. (3) The AE count rates for each grain size decrease with i ncreasing sanding time. (4) The variations with sanding times in the A E count rate and the stock removal rate show similar tendencies. (5) T he AE technique is promising for the monitoring of the performance of belts with sanding times in the wood sanding process.