【作者】 仲为武；

【导师】 赵东标；

【作者基本信息】 南京航空航天大学 ， 机械电子工程， 2012， 博士

【摘要】 自从二十世纪九十年代提出“绿色制造”概念以来，由于人们环保意识的增强和可持续发展战略的提出，绿色制造正在成为制造业的重要特征和基本生产模式。为了提高生产率、工件加工质量和刀具耐用度，传统的金属切削中大量使用切削液。但是切削液的大量使用会对人和环境造成严重的负面影响，而且切削液的使用费用相当高。无论从保护人身健康、生态环境的角度，还是从经济角度考虑，在金属切削过程中不使用或尽可能地少使用切削液都是极其必要的。本文在国家自然科学基金项目（50875120）资助下，对铝合金干切削和少量润滑切削进行研究。首先对干切削和少量润滑切削机理进行了深入研究。以往对金属切削过程的研究没有对振动和声发射信号给予足够关注，本文对干切削和少量润滑切削加工过程中的这两种信号在较抽象的物理信号层面进行系统深入地研究，旨在从一个新的视角揭示干切削和少量润滑切削机理。另外，对干切削和少量润滑切削效果进行了试验研究。最后，在对少量润滑研究的基础上，为了能够在金属切削过程中自适应地提供切削液，提出了基于少量润滑的切削温度监控的构想，并探讨了其可行性，最后进行了试验验证。本文主要研究内容包括：（1）运用传热学理论对干切削和少量润滑切削的热学机理进行了研究。利用普朗特的对流换热边界层理论揭示了少量润滑的冷却机理，提出了切削液处于液态强迫对流换热状态下切削液冷却能力最大时所需最少切削液流量、最大对流换热量计算方法，推导出对流换热量与切削液流量之间关系式；对Zorev提出的刀-屑摩擦模型针对少量润滑条件进行了改进，以对少量润滑条件下的摩擦行为进行更合理地解析；从热量传输角度研究了干切削和少量润滑切削的切削热传输机制；通过对切削液传热模型的研究得到了切削液供液方位和传热参数对切削热传输的影响规律。（2）建立了基于虚拟仪器的干切削加工过程信号采集平台，采样航空铝合金7050-T7451干铣削过程中的振动和声发射信号，从时域和能量角度研究了不同工艺条件下干切削过程的特点和规律。通过时域研究，得到了铣削工艺参数与振动信号、声发射信号的均方根值之间的关系。利用小波包分解，研究了干切削过程中不同工艺条件下振动和声发射信号在不同频带内的能量分布，发现了切削速度、每齿进给量和铣削宽度对信号不同频带能量分布的影响规律。（3）在基于虚拟仪器和VC6.0建立少量润滑切削加工过程信号采集平台和少量润滑切削液供应系统的基础上，对少量润滑切削进行了试验研究。对航空铝合金7050-T7451铣削过程中采样的振动和声发射信号，分别从时域、频域、时频域和信号能量的角度运用多种经典和现代信号处理方法研究了在少量润滑条件下不同切削液流量对切削过程的影响，得到了铣削过程中少量润滑对切削振动信号和声发射信号的均方根值、频谱分布、不同频带能量分布影响的规律。（4）通过航空铝合金和工具钢的铣削试验，对干切削和不同切削液流量的少量润滑切削加工效果从加工质量、对刀具的影响和切屑方面进行对比研究，研究结果表明少量润滑能有效提高加工质量和刀具耐用度。（5）提出并实现了基于少量润滑的切削温度监控的构想。考虑到切削温度与工艺条件之间的强耦合性，运用模糊控制理论设计并开发了基于少量润滑的切削温度监控系统，以期在保证加工质量的前提下尽可能地减少切削液的使用量。对基于少量润滑的航空铝合金7050-T7451切削温度监控进行了可行性研究、仿真和试验研究。仿真和试验结果表明：在少量润滑条件下，通过电液数字阀输出的切削液流量随着切削温度的变化能快速反应，切削温度的控制效果较好，可以实现控制切削温度和减少切削液用量的双重目的。通过加工实例表明了基于切削液的切削温度监控对提高航空铝合金加工质量和减少切削液用量的有效性。论文的研究工作丰富了绿色切削加工理论，研究结果对干切削和少量润滑切削在生产中的应用具有指导作用和实践意义。更多还原

【Abstract】 Due to the increased awareness of environmental protection and sustainable development, greenmanufacturing has been becoming an important feature and a basic production style in modernmanufacturing industry. In order to improve productivity, workpiece quality and to prolong tool life, alarge quantity of cutting fluid is used in metal cutting process. However, extensive use of cutting fluidwill cause serious negative impact on human health and the environment, and the costs of cutting fluidare heavy. From the aspects of human health, the environment, and economics, it’s necessary todecrease the use of cutting fluid as much as possible in metal cutting process.Dry cutting and LQL (A Little Quantity Lubricant) cutting of aluminum alloy are researched inthis paper, supported by the National Natural Science Foundation of China (50875120). Mechanism ofdry cutting and LQL cutting is studied. Compared with previous studies, the characteristic of this paperis that the research of dry cutting and LQL cutting is conducted in a more abstract level through theanalysis of vibration signals and AE (Acoustic Emission) signals. An experimental research isconducted in order to understand the effects of LQL on machining. In addition, in order to providecutting fluid adaptively in metal machining process, the feasibility of cutting temperature control basedon cutting fluid is discussed, and an experimental validation is conducted. The main achivements in thedissertation are summarized as follows:(1) The thermal mechanism of dry cutting and LQL cutting is discussed by applying heat trasfertheory. Cooling mechanism is revealed by applying convective heat transfer boundary layer theory ofPrandtl. The improvement of tool-chip friction model which is suggested by Zorev is conducted inorder to give a more reasonable explanation to the friction behavior between the tool and chip underlubricant condition in machining process, the formula of minimum cutting fluid flow rate when thecooling capacity is the maximm is derived out under the heat transfer condition of liquid forcedconvection. The cutting heat transfer mechanism is researched on dry cutting and LQLcutting from theaspect of heat transfer process. The effect of cutting fluid applying direction and heat trasferparameters on cutting heat trasfer process is researched through heat trasfer model of cutting fluid.(2) A signal acquisition platform is established based on virtual instrument platform. Thevibration signals and AE signals are sampled in milling process of aluminum alloy7050-T7451. Thecharacteristics of signals in dry cutting are researched through the methods of time domain and energydistribution under different process conditions. In time domain, the relationship between process parameters and RMS (Root Mean Square) values is obtained in milling process. By means of waveletpacket decomposition, the energy distribution in different frequency bands of vibration signals and AEsignals in dry milling process is analyzed under different process conditions, revealing the law ofenergy distribution in different frequency bands for different cutting speed, feed per tooth, and cuttingwidth.(3) In order to conduct an experimental research on LQL, a signal acquisition platform isestablished based on virtual instrument platform. A cutting fluid supply system for LQL is built basedon VC6.0. The effects on cutting process of cutting fluid flow rate in LQL milling process foraluminum alloy7050-T7451are researched through the analysis of vibration and AE signals in timedomain, frequency domain, time-frequency domain, and energy distribution in different frequencybands based on wavelet packet decomposition. The characteristics of effects of cutting fluid flow rateto vibration and AE signals are concluded through RMS value, frequency distribution, and energydistribution.(4) Based on the tests of milling of aluminum alloy7050-T7451and tool steel, the comparativeresearch of machining effects of dry cutting and LQL cutting under different cutting fluid flow rate isconducted from aspects of workpiece quality, tool, and chips. The research reveals the advantage ofLQL in metal machining process.(5) By applying fuzzy control theory, a cutting temperature control system for aluminum alloy7050-T7451milling process is established based on LQL in order to decrease the use of cutting fluidwhile assuring the quality of cutting process. A practicability study is conducted. Simulation andexperiment show that the proposed control system can conduct an effective control of cuttingtemperature, and has high control accuracy. The effectiveness of cutting temperature control based oncutting fluid on improving machining quality and decreasing the use of cutting fluid is verified throughmachining experiment.The promising achivements of this dissertation enrich green cutting theory and give a helpfulguide to the application of dry cutting and LQL cutting.更多还原