Recent developments in MQL machining of aeronautical materials:A comparative review

Minimum quantity lubrication(MQL),as a new sustainable and eco-friendly alternative cooling/lubrication technology that addresses the limitations of dry and wet machining,utilizes a small amount of lubricant or coolant to reduce friction,tool wear,and heat during cutting processes.MQL technique has witnessed significant developments in recent years,such as combining MQL with other sustainable techniques to achieve optimum results,using biodegradable lubricants,and innovations in nozzle designs and delivery methods.This review presents an in-depth analysis of machining characteristics(e.g.,cutting forces,temperature,tool wear,chip morphology and surface integrity,etc.)and sustainability characteristics(e.g.,energy consumption,carbon emissions,processing time,machining cost,etc.)of conventional MQL and hybrid MQL techniques like cryogenic MQL,Ranque-Hilsch vortex tube MQL,nanofluids MQL,hybrid nanofluid MQL and ultrasonic vibration assisted MQL in machining of aeronautical materials.Subsequently,the latest research and developments are analyzed and summarized in the field of MQL,and provide a detailed comparison between each technique,considering advantages,challenges,and limitations in practical implementation.In addition,this review serves as a valuable source for researchers and engineers to optimize machining processes while minimizing environmental impact and operational costs.Ultimately,the potential future aspects of MQL for research and industrial execution are discussed.

Elastohydrodynamic Lubrication Performance of Curvilinear Cylindrical Gears Based on Finite Element Method

The fixed-setting face-milled curvilinear cylindrical gear features teeth that are arc-shaped along the longitudinal direction.Some researchers hypothesize that this arc-tooth may enhance the lubrication conditions of the gear.This study focuses on this type of gear,employing both finite element analysis(FEA)and analytical methods to determine the input parameters required for elastohydrodynamic lubrication(EHL)analysis.The effects of assembly errors,tooth surface modifications,load,and face-milling cutter radius on the lubrication performance of these gears are systematically investigated.The finite element model(FEM)of the gear pair is utilized to calculate the coordinates of contact points on the tooth surface and the corresponding contact pressures at the tooth surface nodes throughout a meshing cycle.Subsequently,the normal load on specific gear teeth is determined using a gradient-based approach.Entrainment speed,slip-to-roll ratio,and effective radius near the contact points on the tooth surface are derived through analytical methods.The data obtained from FEA serve as input parameters for EHL simulations.The lubrication performance of the curvilinear cylindrical gear is evaluated through example studies.The findings indicate that using FEA to provide input parameters for EHL simulations can reveal the occurrence of edge contact phenomena during gear meshing,allowing for a more accurate representation of the gear’s lubrication conditions.The lubrication performance of the curvilinear cylindrical gear is shown to be independent of the face-milling cutter radius but is significantly influenced by the size of the contact pattern on the tooth surface.Curvilinear gears with larger contact patterns demonstrate superior lubrication performance.

CMQL和UEV下Incone1690镍基合金切削力和温度分析

低温微量润滑(CMQL)可以使切削阶段达到更优的切削摩擦性能,提升刀具耐磨性能并获得更优减磨效果;超声椭圆振动(UEV)能够提高难加工合金的切削性能。在超声椭圆振动基础上设置低温微量润滑条件,并通过实验分析其切削效果。研究结果表明:采用UEV和CCMQL模式时,切削力与进给力降低比例依次为62.3%与75.0%,在低温微量润滑过程能够实现更低温度控制效果,有效防止工件的热软化问题。普通切削时温度都接近445℃。UEV可以获得更低温度,同时运用UEV和CMQL处理方式,温度下降了16.1%,采用UEV和CCMQL方式时,温度下降19.5%。通过降低喷嘴角度的方式,获得更低切削雾滴温度,刀尖应力出现降低实现刀具保护,促进刀具寿命延长。该研究有助于改善合金切削工艺,对提高切削质量提供了一个思路。

Grindability Evaluation of Ultrasonic Assisted Grinding of Silicon Nitride Ceramic Using Minimum Quantity Lubrication Based SiO_(2)Nanofluid

Minimum quantity Lubrication(MQL)is a sustainable lubrication system that is famous in many machining systems.It involve the spray of an infinitesimal amount of mist-like lubricants during machining processes.The MQL system is affirmed to exhibit an excellent machining performance,and it is highly economical.The nanofluids are understood to exhibit excellent lubricity and heat evacuation capability,compared to pure oil-based MQL system.Studies have shown that the surface quality and amount of energy expended in the grinding operations can be reduced considerably due to the positive effect of these nanofluids.This work presents an experimental study on the tribological performance of SiO_(2)nanofluid during grinding of Si_(3)N_(4)ceramic.The effect different grinding modes and lubrication systems during the grinding operation was also analyzed.Different concentrations of the SiO_(2)nanofluid was manufactured using canola,corn and sunflower oils.The quantitative evaluation of the grinding process was done based on the amount of grinding forces,specific grinding energy,frictional coefficient,and surface integrity.It was found that the canola oil exhibits optimal lubrication performance compared to corn oil,sunflower oil,and traditional lubrication systems.Additionally,the introduction of ultrasonic vibrations with the SiO_(2)nanofluid in MQL system was found to reduce the specific grinding energy,normal grinding forces,tangential grinding forces,and surface roughness by 65%,57%,65%,and 18%respectively.Finally,regression analysis was used to obtain an optimum parameter combinations.The observations from this work will aid the smooth transition towards ecofriendly and sustainable machining of engineering ceramics.

钛合金铣削加工中MQL参数优化与切削性能研究

微量润滑(MQL)铣削过程中,系统工艺参数对刀具–切屑和刀具–工件间接触界面的冷却润滑效果影响显著。本文通过有限元仿真分析了铣刀高速旋转扰动的空气流场对MQL喷射角度的影响以及切削区压力影响下的切削液渗透机理。然后,以钛合金TC4为工件材料、油膜附水滴(OoW)为润滑介质,通过正交试验研究微量润滑系统喷射角度、喷射距离和润滑油流量对铣削力的影响规律,获得油膜附水滴微量润滑(OoWMQL)系统最佳工艺参数为:喷嘴俯角30°、喷射距离10 mm、润滑油流量135 mL/h。基于此,采用OoWMQL系统最优工艺参数,开展干式铣削和水基微量润滑(WMQL)铣削下切削速度、每齿进给量对钛合金切削性能的影响研究。结果表明,相比干式铣削,WMQL方法对铣削力的改善效果较弱,而OoWMQL方法在所有参数下均明显降低了铣削力,且降低幅度最高可达50%左右。此外,采用OoWMQL方法可显著降低表面粗糙度,抑制划痕和粘屑等表面缺陷的产生,有效提高钛合金的切削加工性。

Fluorographene with Narrow Lateral Size and Thickness Distributions Prepared for Enhancing Lubrication Performance of Bentonite Grease

Fluorographene(FG)with narrow lateral size and thickness distributions was prepared by a liquid-phase exfoliation method,based on liquid cascade centrifugation.The Rtec MFT-5000 tribo-meter was used to investigate the lubricating performance of bentonite grease enhanced by the as-prepared FG.The results showed that the coefficient of friction and the wear volume of bentonite grease with 0.3 wt%FG were decreased by 20.4%and 44.9%,respectively,as compared to those of the base grease.The main reason is that FG can promote the formation of the tribo-chemical reaction film consisting of complex carbon oxide,Fe_(2)O_(3)and FeF_(3)on the friction surface,which can remarkably improve the performance of friction reduction and prevent the appearance of severe wear.

航空发动机燃油泵动静压滑动轴承润滑特性与参数影响分析

航空发动机燃油齿轮泵的滑动轴承长期工作在高温、高压和低黏介质极端工况下,极易诱发润滑失效,其润滑性能演变规律尚未完全探明。本文通过建立动静压混合润滑条件下燃油泵滑动轴承流体润滑模型,采用超声测量原理测试了燃油泵真实服役工况下的油膜厚度,验证了多个载荷条件滑动轴承润滑模型的油膜厚度计算准确性。最后,基于试验验证的润滑计算模型,研究了宽径比、偏心率和油槽位置对轴承润滑性能的影响规律。研究结果表明:计算的油膜厚度随工况变化规律与试验测点十分吻合,两者的平均计算误差为2.3%,此外,燃油泵负载增大会使得油膜的最小厚度向进口油槽处偏转,进而导致动压能力减弱,轴承在大负载工况的承载能力主要由静压提供。宽径比B/D由0.4增大至1.2时,会导致油膜温度沿周向降低1.2℃,而沿轴向升高0.5℃,偏心率增大会导致油膜厚度变小,混合润滑轴承中间截面处的动压提升0.43 MPa,设计滑动轴承的油槽位置应开在收敛楔形结构前端或者开扩楔形结构处,能提升轴承承载性能。

含转动副润滑间隙的多连杆机构动力学优化设计

为改善含运动副润滑间隙多连杆机构的动力学特性,以二自由度七连杆机构为研究对象,建立转动副润滑间隙模型,采用拉格朗日乘子法推导出含润滑间隙机构的动力学方程,并通过试验验证了动力学方程的正确性。为优化变量,建立含润滑间隙机构动力学优化模型并利用遗传算法求解。结果表明动力学优化使滑块的加速度降低25%,转动副间隙A、B处的运动副元素之间的作用力分别减小14.8%、18.2%,有效提高了含转动副润滑间隙机构的动力学特性。

MQL加工技术的研究与进展

最小量润滑(Minimum Quantity Lubrication,简称MQL)是一种绿色环保切削加工技术。本文介绍了MQL加工的特点,归纳和总结了其应用研究成果,指出了MQL加工中的关键问题和尚待解决的主要问题,并探讨了其今后的发展趋势。

MQL加工中切削液的作用及性能

MQL加工是可持续发展战略在机械加工中的微观体现,微量切削液的使用可以达到甚至好于传统浇注切削液的加工效果,同时降低成本,减少环境污染。简述了生态效应对MQL切削液的要求,给出了具有生态效应的几种切削液基油和添加剂,并对其生态性能和切削性能进行了比较。为正确制定和实施MQL机械加工工艺提供了理论和工程依据。

MQL切削液的选择

基于化学试验和切削试验,对3种环境友好润滑剂(合成酯、植物油、聚乙二醇)的生物降解性、氧化安定性、储存稳定性、切削润滑性和经济性等方面的性能进行分析研究.运用层次分析法综合考虑切削液的切削效果、环境影响及使用成本等方面构建指标体系,建立研究模型,定性与定量相结合,确定各指标权重,给出3个层次间的模糊关系综合矩阵,对最小量润滑切削加工使用的切削液进行综合分析与评价,结果表明:对于工件45钢,植物油为首选切削液,合成酯其次,聚乙二醇最后;对于工件硬铝LY12,植物油为首选切削液,聚乙二醇其次,合成酯最后.

基于毛细管理论的MQL理论模型及应用

MQL切削加工技术是一项新型的绿色环保加工技术,使用极微量的切削液可以取得良好的加工效果,从而达到保护环境、降低成本的目的。分析了MQL切削加工中切削液的作用原理,基于毛细管理论建立了MQL的理论模型,并进行了MQL精密车削试验,为进一步丰富和发展MQL切削技术奠定了坚实基础。

EFFECT OF COOLING/LUBRICATION MEDIUM ON MACHINABILITY OF Ti6Al4V

To better understand and know the roles of cooling/lubrication medium in the cutting process and expand their applicability,uncoated cemented carbide tools are used in high-speed turning Ti6Al4V.Dry,cold air,minimal quantity lubrication（MQL）,cryogenic MQL,and ionized air as the cooling/lubrication conditions are studied.Experimental results show that at speed 120 m/min turning Ti6Al4V,the cutting force under ionized air is smallest under all lubricant conditions,and tool life is best,next is cryogenic MQL.MQL and cold air almost have the same effect,a little better than dry.Meanwhile the smallest surface roughness is also obtained under ionized air condition.Flank wear and crater wear are the dominant failure modes when high-speed turning Ti6Al4V by SEM analysis.Finally the conclusion is drawn that ionized air and cryogenic MQL have better cooling/lubrication effects and can effectively improve the tool life.

环氧树脂自润滑滑动轴承摩擦磨损性能及其仿真分析

在环氧树脂(EP)中加入一定量的r-GO和不同比例的TiO_(2),研究其对EP材料摩擦磨损性能的影响,并基于滑动轴承接触理论,利用ABAQUS有限元软件对添加r-GO/TiO_(2)/EP自润滑层的滑动轴承进行仿真分析,结果表明,加入r-GO或r-GO/TiO_(2)能显著改善EP材料的摩擦学性能,TiO_(2)质量分数为30%的r-GO/TiO_(2)/EP复合材料的摩擦磨损性能最佳;r-GO/TiO_(2)/EP自润滑层的引入能改善轴承的应力和应变分布。

低温冷风微量润滑技术对TC6钛合金加工特性的应用研究

目的探究机加工中低温冷风微量润滑技术对切削温度、材料塑性变形以及已加工表面质量的影响。方法针对TC6钛合金进行低温冷风微量润滑切削加工应用试验,对比常温干切削和–27℃低温冷风微量润滑切削以及改变加工参数对TC6材料已加工表面缺陷、微观形貌及粗糙度的影响规律,分析低温冷风微量润滑加工应用特点。结果相较于常温干切削,低温冷风微量润滑切削可以明显降低TC6材料在加工中因热量累积而导致的塑性变形,抑制了切削变形区材料与刀具因内摩擦加剧而导致的咬焊现象,减少了已加工表面黏屑、划痕、凹坑、撕裂、侧流等缺陷,有效提高了加工表面质量,与常温干切削加工相比,低温微量润滑切削的表面粗糙度值降低了19%;在加工参数为变量的切削中,提高进给量使已加工表面粗糙度值增加了49%,进给量对已加工表面质量的影响最大;提高背吃刀量使已加工表面粗糙度值增加了43%,背吃刀量对表面质量的影响次之;切削速度对表面质量的影响最小,但背吃刀量和切削速度的增加易使工艺系统产生振动,造成不稳定切削现象。结论将低温冷风微量润滑技术应用在TC6材料的加工上对提高加工质量、满足低碳工业的需求具有一定的帮助。

低温MQL技术在TA15铣削加工中的应用研究

通过在冷却液与低温MQL两种方式条件下,对TA15钛合金材料进行切削试验研究发现:低温MQL状态下加工工件使用的刀具切削寿命更长,工件的切削效率更高,加工的表面质量更好,变形更小。但是其在加工过程中,浅切冷却具有不适应性、加工中产生附加产物对环境的影响、深腔结构的加工冷却不充分等方面具有一定局限性,需进一步研究。

最少量润滑切削技术(MQL)——经济有效的绿色制造方法

综述了由切削液引起的人体病理现象;综合分析了替代或减少切削液用量的干切削、低温冷却、冷风冷却等绿色加工技术的加工效率、经济性及环境友好性;提出最少量润滑切削技术(MQL)是实现清洁、高效制造的最佳工艺方法。

Superlubricity behaviors of Nitinol 60 alloy under oil lubrication

The tribological tests were performed using Nitinol 60 alloy pin sliding over GCr15 steel disc in the tribometer system. Four kinds of oils were experimentally investigated as lubrication oils for lubricating Nitinol 60 alloy in the boundary lubrication regime. The experimental results were compared with a reference dry friction. It was found that Nitinol 60 alloy can be lubricated significantly and has shown remarkable lubrication performance. A superlubricity behavior of Nitinol 60 alloy was observed under castor oil lubrication. An ultra-low coefficient of friction of Nitinol 60 alloy about 0.008 between Nitinol 60 alloy and GCr15 steel was obtained under castor oil lubrication condition after a running-in period. Accordingly, the present study is focused on the lubrication behaviors of castor oil as potential lubrication oil for Nitinol 60 alloy. In the presence of castor oil, coefficient of friction is kept at 0.008 at steady state, corresponding to so-called superlubricity regime （when sliding is then approaching pure rolling）. The mechanism of superlubricity is attributed to the triboformed OH-terminated surfaces from friction-induced dissociation of castor oil and the boundary lubrication films formed on the contact surface due to high polarity and long chain of castor oil allowing strong interactions with the lubricated surfaces.

Lubrication properties of Nitinol 60 alloy used as high-speed rolling bearing and numerical simulation of flow pattern of oil-air lubrication

The friction and wear tests were performed using Nitinol 60 alloy pin sliding over GCr15 steel disk in a pin-on-disk tribometer system under PAO oil lubrication conditions. It was found that Nitinol 60 alloy can be lubricated well and has shown remarkable tribological performance. Average coefficient of friction （COF） of Nitinol 60 is 0.6 under dry friction; however, average COF decreases to 0.1 under PAO oil lubrication. SEM image of the worn surface shows that Nitinol 60 exhibits excellent wear resistance and the wear mechanism is mainly adhesive wear. Flow pattern of oil-air flow in oil pipe was simulated by FLUENT software with VOF model for acquiring working performance of oil-air lubrication. The optimum velocity of oil and air at the inlet was achieved, which provides the great proposal for the design of experiment of oil-air lubrication of Nitinol 60 alloy. The simulation results showed that the optimum annular flow of flow pattern was obtained when air velocity is 10 m/s and oil velocity is 0.05 m/s. The formation mechanism of annular flow was also discussed in the present study.

MQL条件下新型枪钻钻尖断屑性能实验

开发了一种新型的枪钻钻尖——MG钻尖,该钻尖由三段切削刃组成,利用切屑之间相互作用力提高断屑效果。采用分段切削的方法进行钻削试验,发现外刃单独切削产生带状切屑,外刃和圆弧刃同时切削产生切屑变短,三段切削刃同时切削产生的切屑最短。这一现象表明,相邻两段切屑之间的相互作用力能够使切屑变形。通过MG钻尖与标准枪钻钻尖的对比实验,证明MG钻尖的断屑效果优于标准钻尖。