CBN砂轮磨削薄壁球轴承内圈滚道的试验研究

提出了用立方氮化硼(CBN)砂轮代替传统的微晶刚玉砂轮磨削薄壁球轴承内圈滚道的方法,探讨了不同工艺参数对工件表面粗糙度和圆度精度的影响.试验结果表明,当CBN砂轮粒度变细时,可以明显改善磨削表面粗糙度,而对工件圆度值的影响较小;随着进给量增大,加工表面粗糙度值和滚道圆度误差值均增大;随着磨削速比降低加工表面粗糙度值增大.得出了最佳工艺参数为:磨削速比值ν工/ν砂=1/24,磨削进给量0.6 mm/min,砂轮粒度80#;其加工效果为:滚道圆度值由4μm稳定降低至2.5μm范围内,表面粗糙度由Ra 0.42 μm降低至Ra 0.28μm,尺寸一致性提高37%,无烧伤现象;生产率比微晶刚玉磨削提高40倍以上,砂轮耐用度提高50倍以上.     

微晶刚玉砂轮缓进给磨削镍基高温合金GH4169及花键研究

镍基高温合金GH4169作为一种典型的难加工材料,已被广泛应用于航空发动机各类零部件。微晶刚玉砂轮以其优异的自锐性正被逐渐用于磨削加工航空材料。为优选加工高温合金涡轮轴花键的砂轮,使用SG、5SG和TG三种磨料的微晶刚玉砂轮开展高温合金缓进给磨削试验,研究磨料种类对磨削力、磨削温度和表面粗糙度的影响规律。研究结果表明:缓进给磨削高温合金GH4169时,5SG磨料微晶刚玉砂轮的磨削力和温度最小,TG磨料砂轮次之,SG磨料砂轮最大。三种磨料砂轮磨削后的工件表面粗糙度值R_a均在0.3 μm以下。最后,选用5SG磨料微晶刚玉砂轮加工高温合金花键样件,各项检测结果均能满足指标要求。      

微晶刚玉砂轮磨削钛合金TC17磨削力研究

针对航空发动机常用材料钛合金TC17,采用白刚玉砂轮与微晶刚玉砂轮开展磨削试验,研究微晶刚玉砂轮对工件表面质量和磨削力大小的影响规律。试验结果表明:微晶刚玉砂轮磨削后工件表面质量更好,表面粗糙度值降低0.14 μm,磨削力降低10%左右。针对微晶刚玉砂轮进行磨削参数对磨削力影响规律的单因素试验,从磨削力角度分析微晶刚玉砂轮磨削钛合金的合理工艺参数。综合磨削力与加工效率因素,确定磨削钛合金TC17的合理参数为:砂轮线速度v_s=27 m/s、磨削深度a_p=0.01 mm、工件进给速度v_w=12 m/min;对磨削力试验数据进行多元线性回归分析,建立了法向磨削力和切向磨削力的回归模型。      

修整参数对陶瓷cBN砂轮磨削效果的影响

本研究采用陶瓷cBN砂轮加工冷激合金铸铁凸轮,采用金刚石滚轮对砂轮进行在线修整。通过改变修整量、滚轮与砂轮的相对移动速度、修整速比,得出修整参数对砂轮磨削效果的影响规律。研究结果表明,当修整量从5μm×4降低到5μm×3时,工件表面粗糙度从0.25μm增大0.27μm,但仍可满足加工表面粗糙度要求,而砂轮修整量减少1/4,砂轮使用寿命延长;滚轮与砂轮的相对移动速度从0.1 mm/r增大到0.15 mm/r时,工件表面粗糙度值Ra从0.354μm上升到0.452μm,砂轮耐用度从750个工件降低到480个;修整速比增大,工件磨削表面粗糙度增大,当修整速比从0.61增大到1.35时,工件表面粗糙度值Ra从0.2μm增大到0.63μm。     

凸轮加工中陶瓷cBN砂轮修整参数的优化研究

利用金刚石滚轮对陶瓷cBN砂轮进行在线修整,对陶瓷cBN砂轮的修整间隔和修整量进行了优化研究。研究表明:当砂轮修整间隔从50件增加到100件,工件加工表面粗糙度从Ra0.335μm上升到Ra0.350μm,仍然满足工件加工表面的粗糙度要求,可以提高砂轮耐用度一倍;当砂轮修整量从3μm×5降低到3μm×3时,工件加工表面粗糙度从Ra0.350μm上升到Ra0.390μm,但仍可满足工件加工表面的粗糙度要求,而减少砂轮修整量2/5;通过修整间隔和修整量两项修整参数的优化,避免了砂轮的过度修整,节约了成本。     

刚玉砂轮缓进深切磨削K444镍基高温合金研究

为评价K444高温合金的磨削加工性能,采用棕刚玉砂轮和白刚玉砂轮进行磨削试验,对比分析其磨削力、磨削比能、磨削工件的表面形貌和表面粗糙度以及砂轮磨损.结果表明:相比于白刚玉砂轮,棕刚玉砂轮的磨削力更小,磨削后工件表面粗糙度低,其表面粗糙度Ra在0.206～0.455μm,更易获得光滑的磨削表面.对表面粗糙度的敏感度分析...     

金刚石微粉砂轮软弹性修整研究（Ⅵ）──软弹性修整后砂轮的磨削特性

本文以Ｓｉ３Ｎ４工程陶瓷为磨削对象，讨论软弹性修整后金刚石微粉砂轮的磨削力特性及磨削工件表面粗糙度特性，并研究磨削过程中微粉砂轮损耗规律以及工件磨除规律。同时同常规ＧＣ杯形砂轮磨削法修整、电火花法修整进行比较。     

金刚石微粉砂轮软弹性修整研究（VI）：软弹性修整后砂轮的磨削特性

本文以Ｓｉ３Ｎ４工程陶瓷为磨削对象，讨论软弹性修整后金刚石微粉砂轮的磨削力特性及磨削工件表面粗糙度特性，并研究磨削过程中微粉砂轮损耗规律以及工件磨除规律。同时同常规ＧＣ杯形砂轮磨削法修整、电火花法修整进行比较。     

高速立方氮化硼砂轮与绿色制造

以磨削加工汽车发动机凸轮轴、曲轴为例,对陶瓷CBN砂轮与普通刚玉砂轮进行了加工效果对比。结果表明:高速陶瓷CBN砂轮的耐用度是普通陶瓷刚玉砂轮的100倍,寿命是普通砂轮的的44.4倍,而原材料消耗仅为其1/56;加工相同的工件数量,使用刚玉砂轮进行加工,磨料消耗是高速CBN砂轮的400余倍;采用高速陶瓷CBN砂轮代替刚玉砂轮可提高生产效率30%以上,综合生产成本比刚玉砂轮磨削降低60%。高速CBN砂轮具有高效率、高精度、低磨削成本,低环境污染的技术优势,其代表了当今世界磨具产品发展的一个主要方向,是实现绿色加工目标的有效手段。     

CBN砂轮和刚玉砂轮磨削45淬硬钢的对比试验研究

通过分别采用国产陶瓷结合剂CBN砂轮与刚玉砂轮对45淬硬钢工件进行磨削试验，对磨削过程中的参数：磨削比和砂轮磨损进行对比。试验结果表明：砂轮线速度对磨削比有显著影响。①当采用普通速度（Vs=35m／s）对45淬硬钢工件进行磨削时，陶瓷结合剂CBN砂轮的磨削比是白刚玉砂轮的36倍；②当把砂轮线速度Vs提高到50m／s时，陶瓷结合剂CBN砂轮的磨削性能得到了显著提高，其磨削比为白刚玉砂轮的300倍左右。试验结果说明，陶瓷结合剂CBN砂轮在高速磨削条件下，砂轮磨损率低，而且具有较高的磨削能力和效率。     

缓进深切磨削颗粒增强钛基复合材料磨削力的研究

磨削力是磨削过程中的重要参数,同加工效果之间关系密切。使用不同磨料的陶瓷结合剂砂轮进行缓进深切颗粒增强钛基复合材料的磨削试验,研究磨削力与磨削参数和磨料种类的关系。结果表明:普通刚玉砂轮的磨削力是微晶刚玉砂轮磨削力的3~4倍,被加工材料表面更容易产生缺陷。因此,在缓进深切磨削工艺条件下,微晶刚玉砂轮更适合钛基复合材料的磨削。      

钢轨打磨用钎焊金刚石砂轮研究

为解决传统树脂砂轮打磨钢轨时存在的打磨效率低、易烧伤钢轨和粉尘污染大等问题,分析利用钎焊金刚石技术的优势制备新型钢轨打磨用砂轮的可行性。结合磨粒有序排布工艺,制备具有开槽结构的新型钎焊金刚石砂轮,并对U71Mn钢轨钢进行打磨对比试验。结果表明：相较于树脂锆刚玉砂轮,新型钎焊金刚石砂轮能提高50%左右的打磨效率,并有效降低磨削温度,避免钢轨烧伤。在钢轨打磨过程中,新型钎焊砂轮排屑效果显著,基本不发生磨屑黏附现象;但砂轮开槽导致磨削振动增大,加剧金刚石磨粒破碎,并增大钢轨表面粗糙度。新型砂轮磨屑多为带状,磨屑体积大且无熔融小球。     

Rotary dressing model for grinding wheel active surface prediction

A kinematic model of rotary dressing of corundum grinding wheels is presented. Based on wheel and dresser specifications and process kinematics, effects of rotary dressing parametres on wheel topography are predicted. For model validation, wheel surface is characterized by areal roughness parametres, obtaining a deviation less than 15%. Besides, influence of wheel topography on ground part surface quality is investigated. Results highlight the significance of modelling the dressing process and show the model translates into a useful tool for selection of most suitable dressing parametres for achieving specific surface qualities. Moreover, it eases the way to predicting dressing originated defects.     

刚玉磨料显微试样的磨削工艺研究

采用超细树脂金刚石砂轮直接磨削及手工研磨2种方式,对锆刚玉(ZA)、微晶刚玉(SG)、棕刚玉(A)和黑刚玉(BA)4种刚玉类磨料试样制样,通过对其表面粗糙度、显微硬度及表面形貌的对比分析,研究了2种制样方式的质量和效率,并优化了4种刚玉类磨料试样直接磨削制样的工艺参数。结果表明:直接磨削的刚玉类磨料试样表面粗糙度R_a、R_z及显微硬度与手工研磨制样的基本一致,但前者的制样效率比后者高至少2倍;ZA、SG和A磨料直接选用粗磨、精磨工序即可满足显微硬度测试要求,而BA磨料则在粗磨、精磨工序基础上,再增加光磨2次工序,也可达到显微硬度测试要求。      

Influence of different grinding wheel and dressing roller specifications on grinding wheel wear

A targeted adjustment of the dressing results and the methodological influence of the dressing process on the non-stationary wear of a grinding wheel after dressing increases the productivity and the reproducibility of grinding processes. Despite the great economic importance of grinding processes with vitrified corundum grinding wheels and the great relevance of the dressing process for the application behavior of these grinding wheels, quantitative models are missing for the purposeful design of the dressing process. In previous studies, a dressing model was successfully developed which predicts the dressing force in the dressing process as well as the workpiece roughness and the grinding wheel wear behavior in a grinding process for a specific grinding wheel and form roller specification. However, a transferability of this model to other grinding wheel and form roller specifications is not possible because the influence of the grain size and the hardness of the grinding wheel as well as the dressing tool topography on the grinding wheel wear and thus on parameters of the dressing model are not known. The objective of this work was to extend the model to additional grinding wheel and form roller specifications to ensure a broad applicability of the model.     

钢轨材料高速进给干磨砂轮性能研究

钢轨修磨是修复钢轨损伤的主要方式。相比于普通磨削,钢轨修磨对砂轮的磨削加工性能提出了特殊的要求。依据钢轨铣磨车作业工况,设定磨削参数,对不同砂轮进行试验研究,优选符合作业要求的砂轮。试验结果表明:树脂结合剂混合刚玉磨料砂轮耐磨性较好,砂轮的表面有轻微黏附型堵塞;陶瓷结合剂白刚玉大气孔砂轮的磨削效率和耐磨性综合性能较好,砂轮的表面有轻微黏附型堵塞;陶瓷结合剂微晶刚玉砂轮的自锐性好,干磨削效率高,但耐用度极低。      

A new in-feed centerless grinding technique using a surface grinder

This paper deals with the development of an alternative centerless grinding technique, i.e., in-feed centerless grinding based on a surface grinder. In this new method, a compact centerless grinding unit, composed of an ultrasonic elliptic-vibration shoe, a blade and their respective holders, is installed onto the worktable of a surface grinder, and the in-feed centerless grinding operation is performed as a rotating grinding wheel is fed in downward to the cylindrical workpiece held on the shoe and the blade. During grinding, the rotational speed of the workpiece is controlled by the ultrasonic elliptic-vibration of the shoe that is produced by bonding a piezoelectric ceramic device (PZT) on a metal elastic body (stainless steel, SUS304). A simulation method is proposed for clarifying the workpiece rounding process and predicting the workpiece roundness in this new centerless grinding, and the effects of process parameters such as the eccentric angle, the wheel feed rate, the stock removal and the workpiece rotational speed on the workpiece roundness were investigated by simulation followed by experimental confirmation. The obtained results indicate that: (1) the optimum eccentric angle is around 6°; (2) higher machining accuracy can be obtained under a lower grinding wheel feed rate, larger stock removal and faster workpiece rotational speed; (3) the workpiece roundness was improved from an initial value of 19.90 μm to a final one of 0.90 μm after grinding under the optimal grinding conditions.     

一种新型磨胶辊砂轮制造技术

在专利ZL201510030023.1《一种新型磨胶辊砂轮及其制备方法》的基础上,对新型磨胶辊砂轮中的气孔作用机理进行理论探讨。新型磨胶辊砂轮与传统的磨胶辊砂轮相比,不易发生气孔堵塞问题,具有良好的工件加工能力,在磨削工件时不会产生振纹和划伤痕迹,有利于提升工件的加工品质、提高劳动效率。通过试验样品磨削应用反馈:该新型磨胶辊砂轮气孔率达到70%~80%,比一般大气孔碳化硅砂轮高16%以上;回转破裂速度达到120 m/s,比一般大气孔碳化硅砂轮强度提高20%以上;磨削后工件表面光洁度有所提高,修复周期延长2个月以上。并且,通过针对性地选择刚玉空心球粒度,能够制造出具有设计的性能的砂轮,能有效地避免传统磨胶辊多孔磨具的一些问题,比如大气孔碳化硅砂轮常见的烧成黑心、使用强度偏低、成孔剂不环保等问题,同时该新型磨胶辊砂轮的生产工艺性能稳定可靠,易于推广应用。      

Mechanisms in the generation of grinding wheel topography by dressing

For the process of dressing vitrified bonded grinding wheels with diamond tools it has been unknown how the wheel topography is generated. Moreover, the influence of the kinematical dressing parameters on the wheel wear behavior has not been quantified. In the course of this article the grinding wheel was dealt with as a porous ceramic composite. In FEM simulations common dressing forces and usual dressing tool geometries were applied. The results were verified by dressing tests and grinding wheel scratch tests which show the wheel wear mechanisms. The common practice of decreasing the grinding wheel surface roughness by a finishing dressing stroke has to be reconsidered, because previous dressing strokes with higher depths of cut can weaken the grinding wheel structure and lead to an unsteady phase with high grinding wheel wear after dressing.     

钢轨打磨用复合砂轮磨削温度场的研究

为研究钢轨打磨用钎焊金刚石插片复合砂轮磨削时的温度场,用复合砂轮和树脂锆刚玉砂轮在不同压力下磨削65Mn钢工件,并对比其磨削温度。基于试验数据,用有限元法分析复合砂轮磨削钢轨时的温度场。结果表明:随着磨削压力的增大,砂轮产热增大,但复合砂轮磨削产热相对较小。相对于相同条件下用树脂砂轮打磨时,用复合砂轮打磨钢轨时的磨削表面最高温度降低近10%。