金属结合层包覆单列磨粒小直径CBN砂轮端面磨削过程研究

金属结合层包覆单列磨粒小直径CBN砂轮在端面磨削过程中突出高度不同的CBN磨粒相继发生后面磨损、切削刃破碎和脱落,产生了砂轮自锐效应。砂轮磨削力呈现低频起伏和高频波动变化的特征,这是由于磨削过程中CBN磨粒后面磨损钝化使磨削力增大以及随后磨钝磨粒破碎变得锐利使磨削力减小的综合作用结果。砂轮磨削过程受到CBN磨粒性能及其切削刃状态的支配,多晶强韧CBN磨粒(BORAZON550,GE产品)耐磨性改善、磨粒微细破碎保持了砂轮的锐利性,延长了单个磨粒服务时间,突出高度不同的磨粒加入磨削过程的批次效应显著,磨削力低频起伏明显,单晶CBN磨粒(BORAZON500,GE产品)破碎范围大有效降低了磨粒切削刃突出高度、新磨粒加入磨削的过程具有连续性,磨削力高频波动明显。     

金属结合剂杯形小直径CBN砂轮端面磨削沟槽底面时砂轮的自锐效应

金属结合剂杯形小直径CBN砂轮端面磨削沟槽底面时 ,砂轮磨削力不随砂轮累积磨削行程的增加而增大 ,已加工表面粗糙度Rz 稳定在 4μm以下 ,处于持续稳定的正常磨削状态。这缘于磨削过程中CBN砂轮的自锐(Self-dressing)效应 ,即在砂轮磨削的同时砂轮结合剂被连续地去除 (CBN磨粒裸露体积增大 ) ,磨钝磨粒发生龟裂、破碎和脱落 ,不断产生新的磨粒切削刃 ,CBN磨粒切削刃密度保持动态稳定 ,砂轮维持在锋利状态。CBN砂轮自锐效应产生的机理是磨屑与冷却液形成的混合流体对砂轮结合剂产生冲击、冲刷和刻划作用产生了去除砂轮结合剂和梳理磨粒的效果     

小直径CBN砂轮的磨削特性研究

理论分析了小直径ＣＢＮ砂轮平面磨削的特征,弄清了小直径ＣＢＮ砂轮平面磨削时发生ＣＢＮ磨粒早期脱落,是由于磨削过程中单个磨粒最大吃刀量增大,磨粒磨削弧长减小,使磨粒磨削力过大所致。采用减小单个磨粒最大吃刀量和增大磨粒磨削弧长的磨削参数,即小磨削进给速度、大磨削吃刀量（蠕动磨削）和砂轮高密度化可以抑制ＣＢＮ磨粒的脱落,发挥小直径ＣＢＮ砂轮的磨削特性。     

电镀小直径CBN环形砂轮端面磨削沟槽底面

在对小直径环形砂轮端面磨削沟槽底面过程中的磨粒切屑厚度进行解析的基础上,设计了电镀小直径ＣＢＮ环形砂轮端部结构尺寸,作为提高砂轮寿命的措施,实验分析磨削冷却液供给方式和倾斜砂轮轴磨削法的效果。     

杯形CBN砂轮端面磨削的自锐过程分析及磨削效果改善

以曲线沟槽的磨削加工为目的 ,本文对金属结合剂杯形小直径 CBN砂轮端面磨削沟槽底面时的砂轮自锐 (Self- dressing)过程进行了研究。金属结合剂杯形小直径 CBN砂轮的自锐行为表现为磨粒磨损后的破碎产生新切削刃 ,磨钝磨粒的脱落和砂轮结合剂被磨屑去除产生新磨粒 ,保持了砂轮工作面上磨粒密度的相对稳定 ,维持了砂轮的锋锐性。通过提高砂轮硬度以期减缓磨粒脱落 ,增加单个磨粒的服务期限 ,试验结果表明已加工表面粗糙度 Rz小于 3.5 μm,砂轮磨损减小了 40 % ,磨削过程稳定 ,取得了良好的磨削效果     

陶瓷结合CBN砂轮磨削螺纹型面的研究

论述了陶瓷结合CBN砂轮磨削不同类型螺纹——精密滚球丝杠、螺纹丝杠、带表卡尺齿条、千分尺螺杆的试验研究,探讨了陶瓷立方氮化硼砂轮对螺纹型面加工精度、表面粗糙度、砂轮耐用度的影响。     

冷却液及粒度对电镀CBN砂轮端面磨削的影响

实验研究了电镀小直径ＣＢＮ砂轮端面磨削沟槽底面时磨粒粒度、冷却液供给方式对磨削效果的影响。砂轮磨粒尺寸较小时,在砂轮作业面上容易发生切屑粘结和电镀镀粒层剥离等异常损伤;选取较大尺寸的磨粒可以实现砂轮的正常磨削,采用轴心普通冷却液供给和外部高压冷却液供给并用的冷却液供给方法有较长的砂轮寿命,得到的已加工表面粗糙度在Ｒｚ４μｍ以下。     

国产陶瓷结合剂 CBN砂轮磨削45淬硬钢的试验研究

通过采用国产陶瓷结合剂CBN砂轮对45淬硬钢工件进行磨削试验，系统分析了磨削参数对CBN砂轮磨损的影响，获得了能够进行高速高效磨削的合理磨削参数。     

机床特性对陶瓷结合剂CBN砂轮磨削比的影响

通过用陶瓷结合剂CBN砂轮对45淬硬钢工件进行磨削试验,深入分析了机床特性对CBN砂轮磨削比的影响,获得了能够进行CBN砂轮高速高效磨削的机床特征参数。     

砂轮线速度对CBN砂轮磨损影响的磨削试验研究

通过用陶瓷结合剂CBN砂轮对45淬硬钢工件进行磨削试验,深入分析了砂轮线速度对砂轮磨损的影响,获得能够进行高速高效磨削的合理砂轮线速度。     

超硬磨粒CBN砂轮的磨削性能

本研究的目的是评价三种砂轮在磨削高速工具钢时的磨削性能。采用ABWOOD平面磨床,在不同磨削条件下对材料去除率,比磨削能和磨削表面的热损伤进行了实验研究,同时借助专用装置采集了磨削过程中砂轮的动态磨损数据。研究结果表明,超硬磨粒CBN砂轮磨削M2高速钢时磨性能最佳,这种砂轮在硬铁族金属加工领域具有良好的应用前景。     

MODELING OF DRESSING FORCES DURING ROTARY DIAMOND CUP DRESSING OF VITRIFIED CBN GRINDING WHEELS

This paper presents a mathematical model of dressing of vitrified CBN grinding wheels by a diamond cup dresser. It predicts the dressing forces during rotary diamond cup dressing of vitrified CBN grinding wheels. This model is based on the fracture of abrasive grits, the fracture of the bond and the contact forces between dresser and grinding wheel. It considers the kinematical influences and in particular speed ratio and overlap factor during the dressing process. A Weibull distribution is used to predict the probability of bond fracture and also the collision number between the diamond grits of a rotating dresser and the CBN grits. This model is validated by experimental results. The theoretical modeling values agree reasonably well with the experimental results. On the basis of this model the effect of different cup dressing parameters on dressing forces is theoretically discussed with the aim of establishing appropriate dressing process configurations. Furthermore the presented model provides a basis for further prediction of wheel topography and the grinding process.     

STUDY ON A NEW TYPE OF THROW-AWAY SOFT GRINDING WHEELS

0INTROD[JCTIONAbrasivebeltgrindinghasbeenutilizedextensivelyasahigh-efficiencygrindingmethod,especially,ithasmoreadVantagesonnonfermusmetalgrinding['].ComparingwithcommongrindingWheel,itsgrindingefficiencyishighanditsbandingtemperatureislow.Studiesinconnectionwiththismethodincludingseveralaspectsasfollowing:H.Ki.[Zjobtainedthebeltwearprincipleandmeasuredthedistributionofnormalandtangentialforcesbysimulatingbandingconditions;S.HigIJchi[3]presentedamethodwhichachievedhighbandingefficienc…     

AN INNOVATIVE CONCEPT AND ITS EFFECTS ON WHEEL SURFACE TOPOGRAPHY IN DRY GRINDING BY RESIN AND VITRIFIED BOND CBN WHEEL

In the dry grinding process, as there is no coolant lubricant to transfer the heat from the contact zone, minimizing the grinding specific energy and grinding forces is a matter of importance. Some of the results of the systematic research works, based on a novel concept to make a step forward for pure dry grinding, are presented. The new concept is based on the fact that the optimisation of the chip formation reduces the friction and rubbing in the process. Such optimisation was achieved by a special conditioning process. The result showed a drastic reduction in grinding forces and no burning or damages on the surface of workpiece using the novel method comparing to conventional wheel with the same material removal rate. A theoretical discussion is also presented to support the experimental results.     

ON THE CHARACTERISTICS OF HIGH-PERFORMANCE INTERNAL PEEL GRINDING USING ELECTROPLATED CBN WHEELS

The enhancement of material removal rates in hard machining is one major aspect of the applied cutting technologies; to increase the production rates. With respect to the required part quality, emphasis is put on the finishing process as a key element of the process chain. Especially internal finish operations constitute a challenging task because of the complex contact situation. This article presents a recent study on internal peel grinding, using the combined roughing-finishing procedure in combination with the excellent cutting performance of electroplated CBN wheels, to achieve highest removal rates with high surface finish.     

MICRO-DISCONTINUITIES OF THE GRINDING WHEEL AND THEIR EFFECTS ON ITS DURABILITY DURING INTERNAL CYLINDRICAL GRINDING

The article depicts the kinematic parameters of micro-discontinuities and how their shaping methods impact upon the active surface of grinding wheels. It also details the construction of a special device which makes it possible to obtain micro-discontinuities with specific and defined surface configurations and shapes. Experimental research into the effects of shaping the micro-discontinuities of the grinding wheel active surface was realized in the internal deep traverse grinding process. Grinding wheels with a ceramic bond, made from micro-crystalline sintered corundum grains, were utilized in the research. The research investigated the duration of the durability period of the grinding wheels. It also looked at the grinding power, as well as the machined surface roughness, when using grinding wheel with or without micro-discontinuities shaped upon the active surface. As a result of the research undertaken, it was determined that the implementation of micro-discontinuities extends the grinding wheel durability period by at least three times its original duration, while maintaining the desired quality of the machined surface.     

一种新型砂轮平衡装置及其工艺实验的研究

本文论述了砂轮在线液体平衡原理和研制的新型平衡装置。并对系统的微机控制进行了研究。实验结果表明：系统原理正确,平衡精度高,速度快,能显著地提高磨削质量。