An Investigation on Cutting Tool Temperatures in Composite Machining Assisted With Heat-Pipe Cooling
An Investigation on Cutting Tool Temperatures in Composite Machining Assisted With Heat-Pipe Cooling
复制标题
DOI：
10.1115/imece2005-80323
复制
发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Jie Liu;Y. Chou;M. North;K. A. Bennett
中科院分区：
文献类型：
--
作者：
Jie Liu;Y. Chou;M. North;K. A. Bennett
金属基复合材料(MMC)是一种难加工的材料，但只有金刚石刀具被成功地用于这种加工应用。金刚石涂层刀具的磨损特征是涂层的灾难性失效(剥落)，这是由于后刀面磨损表面的工作材料粘在一起，以及涂层-基材界面由于高温而产生的高应力，因为热膨胀系数非常不同。因此，降低温度可以延缓涂层失效的发生，并延长刀具寿命。对一种被动散热装置--热管在金属基复合材料加工中的降温效果进行了试验。虽然热管可以强化换热并合理地降低工具温度，但热管也可能增加工具内的热分配，使其对散热和降温效率的影响复杂化。本文报道了用金刚石涂层刀具加工铝复合材料，并研究了热管对刀具降温的影响。对刀具系统中的热传导进行了数值模拟，以评估无热管和有热管时的刀具温度。建立了包括涂层、刀片基板和刀架在内的刀具系统的三维热模型。热源被描述为切屑-刀具接触区域上前刀面摩擦热流的一部分。为了确定热分配系数，建立了一个独立的2-D芯片模型，该模型包含一个热流密度，平衡了总的前刀面热流密度，并随芯片速度移动。对于刀具和切屑的热模型，通过匹配两个模型的刀具-切屑接触处的平均温度，可以数值确定热分配系数。该模型已被用来评估热管对刀具温度的影响。应用热管冷却不可避免地增加了工具内的热分配，尽管增强了散热。然而，根据加工条件的不同，热管仍然有效地降低了刀具-芯片的接触温度。在使用热电偶进行加工时，也测量了刀具温度。模拟结果与实验测量结果吻合较好。
Metal matrix composites (MMC) are difficult to cut materials, and yet only diamond tools have been successfully utilized for such machining applications. Wear of diamond-coated tools is characterized by catastrophic coating failure (peeling off) due to the adhered work materials at the flank wear-land surface and the high stress developed at the coating-substrate interface, associated with high temperatures, because of very different thermal expansion coefficients. Temperature reductions, therefore, may delay the onset of the coating failure and offer tool life extension. A passive heat-dissipation device, heat-pipe, has been tested for cutting temperature reductions in MMC machining. Though it is intuitive that heat pipes may enhance heat transfer and plausibly reduce the tool temperatures, heat pipes may also increase heat partitioning into the tool, and complicate its effects on the heat removal and temperature reduction efficiency. This paper reports aluminum composite machining by diamond-coated tools and investigates the heat-pipe effects on tool temperature reductions. Numerical simulation of heat conduction in the cutting tool system was performed to evaluate cutting tool temperatures without and with a heat-pipe. A 3-D thermal model of the cutting tool system including coating, insert substrate, and tool holder was established. The heat source was characterized as a heat flux, a portion of the frictional heat flux at the rake face, over the chip-tool contact area. To determine the heat-partition coefficient, a separate 2-D chip model was established with a heat flux, balanced the total rake-face heat flux, over the contact and moving with the chip speed. With the tool and chip thermal models and by matching the average temperature at the tool-chip contact of the two models, the heat partition coefficient can be numerically determined. The model has been used to evaluate how the heat-pipe modifies the cutting tool temperatures. Applying heat-pipe cooling inevitably increases the heat partition into the tool despite the enhanced heat dissipation. However, the heat pipe still effectively reduces the tool-chip contact temperatures, depending upon machining conditions. Cutting tool temperatures have also been measured in machining using thermocouples. The simulation results reasonably agree with the experimental measurements.© 2005 ASME