Thermographic Study on Temperature of Tool-Chip-Work System in Wood Cutting

为了研究切割系统中刀具、切屑和工件的热行为，利用热像仪，在500 mm/min的切割速度和一定的切割深度下，用几种不同间隙和前倾角的刀具对小径白桦进行了正交切削，获得了刀具、切屑和工件侧面的近距离热像。在此基础上，对实际切屑速度量级的较高滑动速度下的刀具温度进行了数值计算。结果表明：1.对于0类和II型切屑，刀具温度在50 mm长的切屑形成过程中迅速升高并达到稳定状态，而对于I型切屑，由于切屑的周期性断裂，刀具温度在切屑形成时呈周期性变化。0型和II型切屑的温度沿长度方向是均匀的，最高温度出现在靠近切边的前刀面上。然而，类型I的芯片只在断裂点显示出明显的温度上升。从数值分析中发现，即使在实际切割速度下，刀具温度也必须升高数百度，且在靠近刀具刃口的前刀面上出现最大值。

In order to examine the thermal behavior of a cutting system, including tool, chip and work, closeup thermal images of the side face of tool, chip and work were obtained using a thermographic device during the orthogonal cutting of mizume (Betula grossa) with a few tools of different clearance and rake angles at a cutting speed of 500 mm/min and at some depths of cut. Furthermore, the tool temperature near the cutting edge in frictional rubbing against wood were numerically calculated for higher sliding speeds of the order of practical cutting speeds.Results are summarized as follows:1. The tool temperature rose rapidly at the beginning of cutting and reached steady states during the cutting of a 50 mm length showing concentric distributions around the cutting edges for the chip formations of Types 0 and II, while it varied periodically for the Type I chip formation due to the cyclic breakage of chips.2. The temperature of chips was uniform along the length of the chips of Type 0 and II and the maximum temperatures appeared on the rake face close to the cutting edge. Chips of Type I, however, showed a distinct temperature rise only at the breaking points.3. It was found from the numerical analysis that the tool temperature must rise several hundreds degrees even in frictional rubbing against wood at practical cutting speeds showing the maximums on the rake face near the cutting edge.