共查询到17条相似文献,搜索用时 78 毫秒
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微量润滑油雾调控及雾粒传输方式直接影响油雾状态的变化,进而影响喷射至切削区域的雾粒特性。基于内置式微量润滑雾化技术和油雾内部传输应用特点,研究了不同微量润滑雾化参数和雾粒传输方式条件下油量调控性能和调控规律,并结合传输管路油雾出口雾粒特征,揭示了油雾传输管路内径和传输行程对雾粒特性的影响规律。研究结果表明,雾化室压差在传输油雾量调控上比进气压力作用显著,需要结合压差和进气压力二者影响来考虑雾化器开启数量以对传输油雾量进行调节,在传输过程中传输管路尺寸与行程是影响油雾雾粒特性的重要因素。 相似文献
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微量润滑(Minimum quantity lubrication,MQL)切削是现代机加工领域一项先进的准干式切削技术,但微量润滑切削过程中产生的切削油雾仍会影响切削现场的环境空气质量,危害切削场所人员的健康。基于重量分析法,对微量润滑条件下的切削现场油雾浓度进行了测量与分析,揭示了润滑油用量、供气压力、喷射靶距、射流温度以及润滑油特性等微量润滑系统参数对切削现场油雾浓度PM10与PM2.5的影响规律。研究结果表明,润滑油用量是影响切削现场油雾浓度的最主要因素,随着润滑油用量的增加,切削现场油雾浓度显著增大,应控制在15 mL/h以内;在射流温度较低的条件下,空气中悬浮的水汽会发生凝结与黏附现象,从而造成低温微量润滑条件下的油雾浓度检测结果较室温条件下明显增大,但低温微量润滑条件下切削现场油雾浓度会随着射流温度的降低而相对降低。 相似文献
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静电雾化微量润滑研究进展与应用 总被引:1,自引:0,他引:1
微量润滑作为替代浇注式供液冷却的可行性方案之一,得到了数十年的发展。然而,气动雾化微量润滑雾滴的表面能逐渐降低;射流的穿透力、吸附力和浸润性能不足,雾滴的漂移和飞溅丧失严重,加大了对环境的污染。静电雾化微量润滑是解决工业生产应用面临技术瓶颈和环保压力的有效方式。首先,系统综述了静电雾化微量润滑关键装置、赋能原理与绿色雾化介质(纳米生物润滑剂)。其次,揭示了微液滴的雾化性能对切削区浸润性能的影响机制,并从荷电液滴静力学的角度阐述了静电雾化微量润滑优异的雾化性能,通过表征雾化介质的荷电性能分析了不同参数对雾化能力的影响机制。进一步地,基于纳米生物润滑剂的脂肪酸分子结构、黏度等理化性质,以及荷电液滴表面状态、空间多能场等,揭示了静电雾化微量润滑改善液滴浸润、渗透以及成膜性能的作用机制,并综述了其在车削、铣削、磨削等工况下对降低刀具磨损、提高加工表面质量的优异性能。在此基础上分析得到:静电雾化优异的雾化特性以及纳米生物润滑剂独特的润滑传热机制,不仅降低了加工环境油雾浓度,还提升了微量润滑的加工性能,具体表现在,与传统微量润滑相比PM2.5/PM10降低约6.2%~68.3%,刀具寿命增加约48... 相似文献
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针对大量浇注式传统切削冷却润滑存在的主要问题,提出并构建了由供液系统、切削液和雾液回收装置所组成的适用于MQL加工的微量切削液冷却润滑系统,并阐述了微量冷却润滑系统对机床、工具系统和刀具兼容性的要求,为制造微量切削液冷却润滑系统和实施MQL加工工艺提供了理论和工程依据。 相似文献
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粗糙表面形貌参数对润滑特性的影响 总被引:1,自引:0,他引:1
在考虑粗糙度效应、时变效应、温升效应和润滑剂非牛顿特性的基础上,采用直接迭代法、逐排扫描法求解润滑方程组和温度控制方程,通过一定的数值计算.探讨了粗糙表面形貌参数对润滑特性的影响。 相似文献
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磨削接触区材料去除厚度是不一致的,同时,在微量润滑过程中,雾滴之间的运动特征存在差异且易受其他因素的影响,致使整个接触区的磨削温度分布呈现出非线性,换热机理也异常复杂。从雾化机理出发,对影响换热效果的两个关键因素--雾滴直径和雾滴速度进行了分析。依据雾滴在不同壁温处表现出的不同换热特性,将磨削区划分为无沸腾换热、核态沸腾换热、过渡沸腾换热和稳定膜态沸腾换热四个不同的换热区域,建立了微量润滑磨削区的换热系数数学模型。在此基础上,运用有限元技术对微量润滑磨削表面的温度场进行了仿真分析,采用单级热电偶技术测量了磨削温度,发现磨削区仿真温度值与实验测量值吻合较好,表明通过该理论获得的微量润滑磨削表面换热系数是可信的。 相似文献
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Minimum Quantity Lubrication (MQL) machining involves the application of a minute amount of an oil-based lubricant to the machining process in an attempt to replace the conventional flood coolant system. Understanding the correlations between fluid properties and MQL performance can help in selecting lubricants from a variety of choices without going through extensive machining tests. This study compared nine different MQL fluids in terms of their physical properties, wettability, tribological properties (lubricity and extreme pressure (EP) properties), mist characteristics and machinability to determine the correlation of measured properties and MQL drilling and reaming performance. Results show that low fluid viscosity, high mist concentration, large mist droplet diameter and high wettability were best correlated with good machinability. Although it is difficult to draw strong relationships, the optimal machining in a mild cutting condition was found with the low viscosity fluids, which may also have the highest mist concentration, largest drops and best wettability. 相似文献
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介绍了微量润滑(MQL)切削技术与传统冷却液加工的现状。对曲轴油道孔钻头在MQL及高转速、大进给的情况下对该钻头打刀进行的分析、优化,最终达到理想的状态。 相似文献
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在构建静电微量润滑(EMQL)磨削加工系统的基础上,分析了不同荷电电压下润滑液液滴的荷质比和润湿渗透性能,研究了正负荷电电压下静电微量润滑技术的磨削加工特性。通过分析工件表层的显微硬度和显微组织,揭示了静电微量润滑技术的磨削加工作用机理。结果表明:荷电液滴的表面张力与润湿角减小,液滴的渗透性和润湿性提高。与传统微量润滑(MQL)相比,荷电液滴更易在砂轮-工件接触面渗透铺展,提升了润滑与换热能力,在正荷电静电微量润滑条件下,工件表层显微组织中的铁素体相对含量增加,工件表层显微硬度降低,磨削加工性能更好。 相似文献
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采用电镀CBN砂轮,以镍基合金GH4169为工件材料,实验研究了两种离子液体的微量润滑磨削加工性能,分别是1-丁基-3-甲基咪唑四氟硼酸盐([BMIM]BF4)和1-己基-3-甲基咪唑四氟硼酸盐([HMIM]BF4),并采用分子动力学模拟,揭示了离子液体在磨粒/工件界面物理吸附膜的形成机制,进一步开展了工件已加工表面的X射线光电子能谱(XPS)分析,揭示了离子液体在磨粒/工件界面化学反应膜的形成机制。研究结果表明:上述两种离子液体适合作为磨削液应用于微量润滑磨削加工中,既能较干磨大幅降低磨削比能和磨削力比,提高工件已加工表面质量,又能较干磨大幅降低磨削温度达100 ℃以上,避免磨削烧伤;磨粒磨钝表面由于微破碎所形成的凹槽状断口是离子液体进入磨粒/工件界面的输运通道,离子液体分子通过吸附在凹槽状断口内形成边界润滑膜,通过减小磨粒工件之间的直接接触面积来减小摩擦力;在微量润滑磨削加工过程中,以上两种离子液体均与工件在磨削界面上发生化学反应,形成了氟化物与氧化物共存的化学反应膜。 相似文献
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Turning is one of the most commonly used cutting processes for manufacturing components in production engineering. The turning process, in some cases, is accompanied by intense relative movements between tool and workpiece, which is called chatter vibrations. Chatter has been identified as a detrimental problem that adversely impacts surface finish, tool life, process productivity, and dimensional accuracy of the machined part. Cooling/Lubrication in the turning process is normally done for some reasons, including friction and force reduction, temperature decrement, and surface finish improvement. Wet cooling is a traditional cooling/lubrication process that has been used in machining since the past. Besides, a variety of new cooling and lubricating approaches have been developed in recent years, such as the minimum quantity lubrication (MQL), cryogenic cooling, nanolubrication, etc., due to ecological issues. Despite the importance of cooling/lubrication in machining, there is a lack of research on chatter stability in the presence of cutting fluid in cutting processes. In this study, the chatter vibration in turning process for two cooling/lubrication conditions of conventional wet and MQL is investigated. An integrated theoretical model is used to predict both the metal cutting force and the chatter stability lobe diagram (SLD) in turning process. This model involves deriving a math equation for predicting metal cutting force for both wet and MQL conditions using experimental training force data and a Genetic Expression Programming (GEP)-based regression model. Also, the traditional single degree of freedom chatter model is used here for predicting the SLDs. The chatter model is discussed and verified with experimental tests. Then, the experimental results of the tool's acceleration signal, work surface texture, surface roughness, chip shape, and tool wear are presented and compared for wet and MQL conditions. The results of this study show that the cooling/lubrication systems such as wet or MQL have a considerable effect on the SLDs. Also, the predicted results of metal cutting force and SLD for both wet and MQL techniques are in good agreement with the experimental data. Therefore, it is recommended that for each lubrication condition including wet, or MQL, the SLD be determined to achieve higher machinability. 相似文献