铝合金Al6061微尺度磨削力热特性试验分析

微磨削加工是微尺度加工领域的一种重要的加工方法。基于铝合金Al6061建立微磨削力热特性的理论模型。设计铝合金Al6061材料的微磨削单因素试验,分析试验结果得出不同磨削参数对微磨削力和磨削温度影响规律。针对不同的磨削深度,研究微磨削表面温度和表面下不同深度位置的温度分布情况,并对加工表面进行热烧伤检测。根据试验数据结果对所建立微磨削力和微磨削温度的理论模型的准确性进行了验证,并通过试验测量得到微磨削后最高表面温度为78.5 ℃。试验研究结果也为进一步研究零件表面完整性和提高零件表面质量提供重要依据。     

硬脆材料微磨削表面形成机理试验研究

微磨削作为微尺度硬脆材料元器件的一种重要加工方法越来越受到重视,分析硬脆材料微磨削材料去除机理、提出其应为脆性去除与延性去除的综合作用,并就硬脆材料微磨削中材料去除过程与传统磨削方式的不同建立微磨削表面形成模型。为揭示硬脆材料微磨削过程的表面形成机理,验证所提出的微磨削未变形切屑厚度hm与微磨削表面粗糙度Ra计算模型的科学性和准确性,针对钠钙玻璃这一典型硬脆材料设计了正交微磨削试验,就试验结果进行硬脆材料微磨削表面形貌分析,讨论硬脆材料微磨削表面影响因素以及影响规律。基于试验数据结果对所建立微磨削模型的科学性进行了验证,并通过试验获得了微磨削后表面粗糙度Ra从78 nm至0.98 μm的一系列表面,为硬脆材料微磨削表面形成机理研究提供了理论参考与试验依据。     

硬脆材料微磨削延性域复合临界条件建模及试验研究

分析硬脆材料微磨削表面形成机理并建立了微磨削槽磨未变形切屑厚度hm数学模型,引入微尺度效应系数Md、延性域系数与延-脆性域系数ζ0与ζ1,针对硬脆材料特性提出微磨削延性域,延-脆性域复合临界条件模型。基于精密微磨削机床进行钠钙玻璃与单晶硅这两种典型材料的微尺度槽磨磨削试验,通过对试验结果分析得出两种材料微磨削表面裂纹变化规律。基于实际试验数据结果对提出的硬脆材料微磨削复合临界条件模型进行验证,证明了所提出模型的科学性。分别给出钠钙玻璃与单晶硅的延性域与延-脆性域微磨削加工参数a0与a1,为硬脆材料微磨削延性域临界磨削条件研究提供了理论参考与试验依据。     

基于响应曲面法的微磨削钛合金表面粗糙度预测分析

微磨削以极高的加工精度和灵活的加工特性在微宏制造领域越来越受到重视。针对钛合金工件的微磨削,运用二次回归正交旋转组合设计方法安排了19组试验,并结合响应曲面法(RSM),分析了微磨削过程中主轴转速、进给速度、磨削深度对表面粗糙度的影响规律。结果表明:在本文的工艺参数范围内,进给速度对微磨削表面粗糙度的影响最大,主轴转速次之,磨削深度影响最小。运用该预测模型,获得了Ra为163nm的磨削表面,为优化微磨削参数和控制表面质量提供依据。     

电镀金刚石微磨具磨损机理分析与试验研究

微磨削加工中磨粒的微观作用机理对研究微磨具的整体磨损和微磨具使用寿命的预测十分重要。分析电镀金刚石微磨具的磨损机理,针对微磨削区的复合作用过程与微磨具磨损形式的主要特征进行了几何与数学建模。通过考虑最小切屑厚度与尺寸效应等因素后提出并建立了微磨具磨粒微观磨损的数学模型,为了验证此模型的有效性,针对钠钙玻璃材料进行了不同磨削参数下的微磨削试验,分析微磨具磨损前后的磨头直径、磨损与破碎磨粒所占磨粒总数的比例和加工后试件表面粗糙度的变化规律。试验结果表明:加工后的试件表面质量越好磨损越缓慢;随着微磨削试验的进行,微磨具磨头直径经历了快速急剧减小和缓慢稳定减小两个阶段。磨损和破碎磨粒所占比例与磨损速度随主轴转速与进给率增大而增大,磨损和破碎磨粒的比例整体呈线性增长趋势。为提高微磨具的加工性能和延长微磨具的使用寿命提供了理论参考和试验依据。     

磨削参数对合金材料加工过程中磨削力及表面粗糙度的影响

针对合金材料磨削加工中磨削参数对磨削力和加工表面粗糙度的影响,以轴承合金材料为例,设计了GCr15和42CrMo两种高碳铬轴承材料的平面磨削试验。采用白刚玉砂轮完成三因素四水平正交试验,使用切削力测量系统、三维轮廓仪和超景深三维显微系统进行磨削力和表面粗糙度的数据采集,用于后续分析磨削力和表面粗糙度受磨削参数的影响规律。对试验设备采集数据进行均值分析发现：磨削参数对于磨削加工过程中产生的磨削力和表面质量的影响程度分别是磨削深度>砂轮转速>进给速度。本文研究结果对实际磨削加工的磨削参数优化有一定指导意义。     

超硬涂层磨削工艺实验研究

针对核主泵关键部件材料镍基碳化钨涂层,采用三种磨粒粒度金刚石砂轮进行平面磨削试验,研究工艺参数、磨粒粒度对涂层材料磨削力、表面粗糙度和表面残余应力的影响规律。实验结果表明:不同粒度砂轮磨削时,随着磨削深度和工件进给速度增加,法向磨削力和切向磨削力均逐渐增大,表面粗糙度值呈现先增大、后减小再增大的趋势,平行和垂直磨削方向的表面残余压应力逐渐增大,且垂直磨削方向应力值更大。综合考虑磨削力、表面粗糙度、磨削表面残余应力和磨削加工效率,600目砂轮具有较好的加工效果,其对应的优化磨削参数为:磨削深度为10μm,工件进给速度为8 m/min。     

工程陶瓷镜面磨削新方法及其机理的研究

基于各种磨削参数对氧化铝砂轮磨削氪化硅工程陶瓷材料表面粗糙度影响的试验研究．提出了氧化铝砂轮加工工程陶瓷时的作用过程可分为氧化铝砂粒与工件表面的凸峰碰撞破碎去除，碰撞与摩擦共同作用及摩擦抛光三个阶段，并建立了各阶段的去除模型。而后通过对不同磨削参数的工件加工表面进行微观观察，证明了上述加工机理的存在，并能获得良好的表面质量，达到了镜面加工要求，实现了在普通磨床上对陶瓮材料的高质量加工。     

轴承套圈ELID磨削参数研究

采用在线电解(ELID)磨削技术对轴承套圈进行精密磨削实验,研究了在相同的磨削时间内不同导电率的磨削液对工件表面粗糙度的影响规律,以及同一导电率的磨削液随着磨削时间变化对工件表面粗糙度的影响规律,利用正交试验法对轴承套圈的工艺参数进行优化设计,试验结果表明,当磨削液导电率在合理的范围内时,磨削液的导电率越大,工件的表面粗糙度就越小,对于同一导电率的磨削液,随着磨削时间的增加,工件表面粗糙度呈现小幅度的增大,利用正交试验优化得出的方案提高了轴承套圈的加工精度。     

2.5D Cf/SiC刹车材料浮动磨削工艺试验研究

为研究2.5D C_f/SiC刹车材料的浮动磨削加工性能,设计单因素试验探究了砂轮转速、工作台调定压力和磨削深度对磨削力、表面粗糙度和表面形貌的影响规律,分析了磨削表面典型加工缺陷及材料去除机理。结果表明：砂轮转速、工作台调定压力和磨削深度对法向磨削力影响显著,对切向磨削力影响不大;工作台调定压力对表面粗糙度的影响程度最大。2.5D C_f/SiC刹车材料以脆性断裂去除方式为主,不同纤维方向上的加工缺陷形式存在差异,其主要加工缺陷为界面脱粘、微裂纹、基体破碎、纤维剥离及破碎。试验通过单因素方法分析得到了较好的表面质量,表面粗糙度Sa可达0.6μm左右。     

Modeling and evaluating of surface roughness prediction in micro-grinding on soda-lime glass considering tool characterization

The current research of micro-grinding mainly focuses on the optimal processing technology for different materials. However, the material removal mechanism in micro-grinding is the base of achieving high quality processing surface. Therefore, a novel method for predicting surface roughness in micro-grinding of hard brittle materials considering micro-grinding tool grains protrusion topography is proposed in this paper. The differences of material removal mechanism between convention grinding process and micro-grinding process are analyzed. Topography characterization has been done on micro-grinding tools which are fabricated by electroplating. Models of grain density generation and grain interval are built, and new predicting model of micro-grinding surface roughness is developed. In order to verify the precision and application effect of the surface roughness prediction model proposed, a micro-grinding orthogonally experiment on soda-lime glass is designed and conducted. A series of micro-machining surfaces which are 78 nm to 0.98 ~tm roughness of brittle material is achieved. It is found that experimental roughness results and the predicting roughness data have an evident coincidence, and the component variable of describing the size effects in predicting model is calculated to be 1.5x 107 by reverse method based on the experimental results. The proposed model builds a set of distribution to consider grains distribution densities in different protrusion heights. Finally, the characterization of micro-grinding tools which are used in the experiment has been done based on the distribution set. It is concluded that there is a significant coincidence between surface prediction data from the proposed model and measurements from experiment results. Therefore, the effectiveness of the model is demonstrated. This paper proposes a novel method for predicting surface roughness in micro-grinding of hard brittle materials considering micro-grinding tool grains protrusion topography, which would provide significant research theory and experimental reference of material removal mechanism in micro-grinding of soda-lime glass.     

强化研磨时工件转速对轴承套圈表面加工质量的影响

强化研磨是一种基于复合加工方法的抗疲劳、抗腐蚀、抗磨损金属材料精密加工技术,利用该技术可加工出具有残余应力的轴承套圈。为了提高强化研磨轴承套圈的加工质量,在其他工艺参数保持不变的情况下,对工件转速进行了单一变量试验,通过检测轴承套圈内圈沟道表面粗糙度与硬度的变化,分析了工件转速对加工质量的影响及作用机制。     

微细磨削技术及微磨床设备研究现状分析与探讨

采用微磨床及微磨具的微细磨削技术,可以实现多种材料复杂形状三维微小零件的加工,且设备体积小、能耗少、成本低,已受到国内外研究人员的广泛关注。但是目前微细磨削技术的研究还处于起步阶段,在微细磨削机理、微磨床及微磨具等方面存在大量问题需要解决。因此非常有必要深入分析微细磨削技术的研究现状、存在的问题及发展趋势。明确了微细磨削技术的内容范畴;全面总结了微细磨削机理及工艺、微磨床及其关键部件、微磨棒等方面的研究现状;在此基础上,深入探讨了微细磨削技术在磨削机理及工艺、微磨床和微磨棒等方面存在的基础性问题,并进一步指出微细磨削技术还应关注其向多种材料应用、复合化加工、高效高精及智能化柔性化的发展方向,以期促进微细磨削技术在我国的推广应用,提升我国超精密微小零件的加工制造水平。     

Study on minimum quantity lubrication in micro-grinding

This paper discusses the performance of the minimum quantity lubrication (MQL) in micro-grinding based on ground surface roughness and tool life. The effects of grinding and lubricating parameters on machining performance are studied. Experiments for dry grinding and grinding with pure air are also conducted for comparison. It is observed that surface roughness and tool life are improved with the application of MQL in micro-grinding. Experimental results show that efficient chip removal from the cutting zone in micro-grinding is important for achieving good surface finish and adequate tool life. The application of a small amount of cutting oil in MQL can significantly extend the tool life. In this study, the tool life in MQL is seven times longer than that in dry grinding and five times longer than that in grinding with air cooling. If the oil flow is surplus to requirements or the air flow is inadequate, excess oil will stay on the grinding tool after the grinding test. As a result, poor surface roughness is observed. The optimal lubrication conditions in this experimental exploration are the combination of an oil flow of 1.88?ml/h and an air flow of 25?L/min.     

Experimental study on fabrication and evaluation of a micro-scale shaft grinding tool

This paper presents a micro-grinding experiment on AISI 1020 steel and Ti-6Al-4V to study micro-grinding principle and the change rule of the force and surface with different grinding parameters. A novel micro shaft grinding tool is fabricated by cold sprayed with CBN grains, the manufacturing is carried out on a desktop micro machine developed by NEU. Influences caused by particle size on surface quality has been discussed, it has been tested that low surface roughness could be achieved on 3000 particle size of micro shaft grinding tool, the roughness of AISI 1020 steel accomplished in the experiment is about 0.086 μm. Measured micro-grinding force of Ti-6Al-4V decreases with the increasing spindle speed and the decreasing cutting depth. The surface roughness decreases with the increasing spindle speed and the decreasing feed rate. The minimum surface roughness is 325 nm with the spindle speed of 48000 r/min and the feed rate of 20 μm/s.     

Modeling and simulation of grinding surface topography considering wheel vibration

Grinding is an important means of realizing precision and ultra-precision machining. Vibration caused by an unbalanced grinding wheel in grinding process has a significant impact on the quality of workpiece surface. However, the effect of wheel surface topography and/or the relative vibration between grinding wheel and workpiece are not considered in most researches. Taking the relative vibration between grinding wheel and workpiece into account, alongside the abrasive grain trajectory equation, a new analysis and simulation model for surface topography of the grinding process is established. The model for the topography of the grinding wheel surface is first studied, and subsequently, a new simulation model for surface topography of the grinding process is proposed. Case studies are performed at the end, and the influence of grinding wheel vibration amplitude, wheel grit number, as well as grinding parameters on the surface waviness and roughness is discussed. The simulation results could be used to optimize the actual grinding process to improve the ground surface quality or predict the surface topography by given grinding parameters.     

Cu-3镍铜合金砂带磨削试验研究

分析了Cu-3镍铜合金砂带磨削加工过程中,砂带粒度和磨削用量的不同对磨削加工效率、工件表面质量和砂带磨损的影响。采用氧化铝磨料砂带在不同的砂带线速度或磨削压力下对镍铜合金进行了工艺试验,对材料去除量、工件表面粗糙度和砂带磨损量进行了测量。研究表明:增加砂带线速度和磨削压力可在一定程度上提高材料去除率和磨削比;随着磨削压力的增大,工件表面粗糙度呈增大趋势;随着砂带粒度的增大,工件表面粗糙度呈减小趋势;砂带线速度为25m/s,磨削压力为43N,砂带粒度为P240时,镍铜合金综合磨削效果最好。     

Experimental study on ductile-regime micro-grinding character of soda-lime glass with diamond tool

This paper proposes a model to predict the material removal mode in soda-lime glass micro-grinding. This model defines material removal process to three stages which conclude ductile type, ductile-brittle type and brittle type by the quantization of undeformed chip thickness h _m . The model for computing undeformed chip thickness in micro-grinding has been built considering tool topography, grit distribution and size effect in this paper. Micro-grinding experiments with different cutting depth on soda-lime glass have been designed and conducted. From experiment results, it was found that the edge crack length tends to have a wide range with different h _m . Three types of chip have been investigated in results, and coolant has been verified to be an important factor to soda-lime glass ductile-regime micro-grinding. Critical depths of soda-lime glass micro-grinding have been found to be 2 and 5 nm, grinding forces in experiment provide the proof to predictive model proposed by this paper.