In-process Detection of Wear and Fracture of Wood Cutting Tool.

刀具磨损或切削状态的在线监测技术对木材加工过程的自动化具有重要意义。本论文对声发射技术在刀具磨损和表面光洁度在线检测中的应用进行了基础性研究，主要研究结果如下：1.切削过程中产生的声发射信号与连续声发射类型比较相似.磨损刀具的声发射水平比锋利刀具的低.声发射水平随切削深度的增加而增加，随切削速度的增加而显著增加.采用振铃计数法得到的声发射计数率可以有效地表征切削过程中产生的声发射信号。5. AE信号的峰值主要在0.1-0.3 MHz的频率范围内检测到。对着磨粒切削时产生的声发射信号非常高，从上述结果可以看出，声发射信号对刀具磨损和磨粒倾角的变化非常敏感。因此，AE信号的使用是有希望的过程中检测刀具磨损或切削表面的缺陷（撕裂的颗粒和碎片颗粒）。

The in-process monitoring technique of cutting tool wear or cutting conditions is important for the automation of wood machining operation. In this study, the fundamental research on the in-process detecting method of cutting tool wear and surface finish have been carried out by making use of acoustic emission(AE).The results are summarized as follows:1. The AE signal generated during cutting is comparatively similar to the continuous AE type.2. The AE level for a worn tool decreases in comparison with that for a sharp tool.3. The AE level increases with increasing depth of cut and remarkably with increasing cutting speed.4. The AE count rate obtained by ringdown counting method is effective to characterize the AE signal generated during cutting. 5. The peak of AE signal is detected mainly in the frequency range at 0.1-0.3 MHz.6. The AE signal generated during cutting against grain is remarkably high.From the above results, it was found that the AE signal was sensitive to changes in the tool wear and the slope angle of grain. Accordingly, the use of AE signal is promising for in process detection of tool wear or defects of cut surface(torn grain and chipped grain).