高速钢材料的粗金刚石砂轮轴向进给数控磨削机理研究

根据正交试验确定了影响高速钢材料的粗金刚石砂轮轴向进给数控磨削表面粗糙度值Rα的最主要因素是进给速度Vfo。在此基础上，进行进给速度巧单因素数控磨削实验，对数控磨削后表面粗糙度值进行了分析。分析结果表明，要用粗金刚石砂轮进行轴向精密加工，采用具有较多的磨粒数且磨粒均匀分布在轴向和周向的砂轮和采用较低的进给速度对精密加工更有利。     

光学自由曲面反射镜模芯的镜面成型磨削

采用精密修锐修整的圆弧形粗金刚石砂轮在CNC精密磨床上进行了数控成型磨削加工,实现了高效镜面磨削。分析金刚石砂轮圆弧形轮廓的成型修整原理,建立了圆弧形修整的数控模式。通过建立曲面数控成型磨削的行走轨迹算法,实现了自由曲面的圆弧包络成型磨削加工。分析了磨削工艺参数和砂轮出刃形貌参数与超光滑表面形成的作用机制,进行了镜面磨削试验并检测表面微观形貌和粗糙度,分析实现镜面磨削的脆/塑性磨削转换机理。理论分析表明,降低砂轮行走速度,提高砂轮转速以及改善出刃形貌可以获得纳米级粗糙度的超光滑磨削表面。试验结果显示,先将砂轮修锐修整再控制砂轮行走速度小至15 mm/min时,表面粗糙度小于10 nm以下,且微观加工表面没有发生脆性破坏,形成镜面。加工高速钢自由曲面时,面形误差(PV值)可以达到10 μm以下,表面粗糙度R_a可以达到约16 nm。实验结果表明:利用数控技术和粗金刚石砂轮可以实现自由曲面模芯的高效镜面磨削加工,保证了高精度的光学自由曲面反射镜注塑模芯。     

树脂结合剂金刚石砂轮磨削铁氧体陶瓷表面粗糙度的试验研究

通过磨削对比试验研究了树脂结合剂金刚石砂轮的特性参数和磨削用量对铁氧体陶瓷表面粗糙度的影响;通过砂轮速度、磨削深度、横向进给速度和纵向进给速度等四因素及各因素之间交互试验的数据分析和金相显微图像比较,探讨了各因素对陶瓷表面粗糙度的影响规律,并优化了降低表面粗糙度的磨削参数。     

氧化铝陶瓷缓进给磨削机理的研究

本文通过扫描电子显微镜对氧化铝陶瓷缓进给磨削后的表面进行详尽的观察，对氧化铝陶瓷的磨削机理进行研究。研究表明对氧化铝陶瓷进行缓进给磨削时，主要以脆性崩碎方式去除材料，并伴随着一定量的塑性流动，给出了氧化铝陶瓷在缓进给磨削方式下无裂纹磨削方法。同时研究了磨削参数对表面粗糙度的影响，实践证明工程陶瓷材料以缓进给方式磨削和特定的磨粒粒度下表面粗糙度Ra值是稳定的。     

陶瓷结合剂金刚石砂轮磨削超细晶粒硬质合金的表面粗糙度研究

本文结合单因素实验和正交实验,研究了从低速到高速磨削条件下,砂轮速度、进给速度、磨削深度、最大未变形磨削厚度以及磨削方式(顺磨或逆磨)对陶瓷结合剂金刚石砂轮磨削超细晶粒硬质合金表面粗糙度的影响规律,分析了影响超细晶粒硬质合金表面加工质量的原因。研究表明,总体来说磨削参数的变化对超细晶粒硬质合金表面粗糙度的影响程度不大。高速磨削时的表面粗糙度相比低速磨削得到了比较明显改善。逆磨时的粗糙度比顺磨大,随砂轮速度增加下降更快。相比传统硬质合金,磨削WC颗粒更细、强度更高的超细晶粒硬质合金的表面粗糙度更低。磨削参数对表面粗糙度的影响程度从小到大依次是磨削深度、砂轮速度和进给速度,实际加工时为同时获得较高的磨除率和表面质量,宜采用高砂轮速度、低进给和大切深的磨削组合。     

单晶材料微磨削表面粗糙度与磨削力实验研究

为了探究微磨削对单晶DD98表面粗糙度与磨削力的影响,采用磨粒为500#和磨头直径为0.9mm的磨棒对单晶DD98进行微磨削实验。首先,设计三因素四水平正交实验,通过极差分析得到磨削参数在一定范围内对表面粗糙度影响的主次顺序,其中磨削深度影响最大,主轴转速次之,进给速度最小;并获得最优工艺参数水平组合:主轴转速为60000r/min,磨削深度为6μm,进给速度为20μm/s。其次,对单因素实验进行微磨削实验,得到在一定范围内,得到表面粗糙度值和磨削力值都随主轴转速的增大、磨削深度的减小、进给速度的减小而减小,并对这种影响规律进行分析。为单晶DD98的微磨削提供了重要的理论基础。     

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。     

滚珠丝杠粗糙度和螺距误差影响因素的正交分析

针对表面粗糙度和螺距误差对滚珠丝杠性能的影响,通过正交试验对磨削过程中影响滚珠丝杠粗糙度和螺距误差的因素:砂轮转速、修整进给速度、丝杠转速、磨削深度进行试验探究,确定各因素对滚珠丝杠性能影响的主次顺序和最佳组合。研究发现,磨削过程中,粗糙度最小的工艺参数组合为砂轮转速1 144 r/min,修整进给速度208 mm/min,丝杠转速16 mm/min,切削深度2μm。以上参数影响滚珠丝杠表面平均粗糙度的主次顺序为:砂轮转速→修整进给速度→磨床丝杠转速→切削深度。螺距误差最小的工艺参数组合为砂轮转速1 144 r/min,修整进给速度208 mm/min,丝杠转速16 mm/min,切削深度1μm。以上参数影响滚珠丝杠螺距误差的主次顺序为丝杠转速→磨削深度→修整进给速度→砂轮转速。     

数控曲线磨削精度分布规律研究

以正交试验设计理论为依据,结合数控加工技术的特点,给出了数控曲线磨削加工精度分布规律的正交试验设计方案,进行以薄板为加工工件的数控磨削加工试验。根据试验数据用MATLAB对薄板曲线部分的圆度误差进行模拟,验证了数控磨削加工的圆度误差符合正态分布规律;用极差分析法进行圆度误差分析,研究加工参数对精度影响的显著性差异。指出影响数控加工表面粗糙度精度分布趋势的主要因素,并在Matlab中模拟了数控曲线磨削表面粗糙度值的分布趋势。     

直线成形面数控展成磨削技术研究

研究在数控平面磨床上利用碟形砂轮对直线成形面进行精密磨削加工。综合直线成形面的常见磨削技术,采取数控展成加工的原理,利用数控平面磨床的两轴联动,用碟形砂轮或斜边砂轮对直线成形面进行展成磨削。分析数控展成磨削的磨削原理、表面成形机理、砂轮的修整技术以及砂轮的安装误差和形状误差、磨削的进给行距及数控系统等因素对成形面精度的影响,得到了直线成形面的数控展成磨削新技术。     

Recognition of diamond grains on surface of fine diamond grinding wheel

The accurate evaluation of grinding wheel surface topography, which is necessary for the investigation of the grinding principle, optimism, modeling, and simulation of a grinding process, significantly depends on the accurate recognition of abrasive grains from the measured wheel surface. A detailed analysis of the grain size distribution characteristics and grain profile wavelength of the fine diamond grinding wheel used for ultra-precision grinding is presented. The requirements of the spatial sampling interval and sampling area for instruments to measure the surface topography of a diamond grinding wheel are discussed. To recognize diamond grains, digital filtering is used to eliminate the high frequency disturbance from the measured 3D digital surface of the grinding wheel, the geometric features of diamond grains are then extracted from the filtered 3D digital surface, and a method based on the grain profile frequency characteristics, diamond grain curvature, and distance between two adjacent diamond grains is proposed. A 3D surface profiler based on scanning white light interferometry is used to measure the 3D surface topography of a #3000 mesh resin bonded diamond grinding wheel, and the diamond grains are then recognized from the 3D digital surface. The experimental result shows that the proposed method is reasonable and effective. __________ Translated from Journal of Dalian University of Technology, 2007, 47(3): 358–362 [译自: 大连理工大学学报]     

Precision cylindrical face grinding

The mathematical models and experimental validations of precision cylindrical face grinding using a narrow ring superabrasive wheel are presented. The high pressure seal in diesel engine fuel systems demands the μm-scale form tolerance specifications and has driven the development of precision face grinding using the superabrasive wheel. Two mathematical models were developed: one was applied to predict the convex or concave face profile and another was used to simulate the abrasive trajectories, which become the cross-hatch grinding marks on the ground face. Cylindrical face grinding experiments were conducted. Experimental measurements of face profile and abrasive trajectories were used to validate the theoretical results. For high-pressure sealing surfaces, the height of face profile and grinding trajectories were two critical characteristics for design and manufacturing. Two design tools, a linear approximate solution for the profile height and an atlas for grinding trajectories, were developed to assist the selection of process parameters for the machine setup.     

砂轮平衡及其在磨削工程中的应用

在机械制造领域,磨削加工以其不可替代的优势,通常作为机械零件的最后加工工序.但是,磨削加工过程中却时常出现振动,致使磨削振纹成为提高零件表面质量的主要障碍.为此,全面梳理了回转体不平衡、砂轮不平衡、磨削振动和砂轮平衡精度等相关内容;分析了砂轮平衡主要表征参数、砂轮不平衡影响因素和砂轮平衡测试技术等;最后,基于磨削工程应...     

普通磨床超精度磨削工艺及工艺参数选择

通过对超精度磨削机理的研究和分析，在ME1432B普通外圆万能磨床上．采用精、细修整砂轮．使砂轮上的同一颗粒等高微刃数增多的方法，达到磨削抛光作用，并对磨床导轨、砂轮主轴与轴瓦间隙进行修刮和调整，同时合理选择磨削工艺参数等方面达到超精磨削的目的。     

轴承零件磨削烧伤和磨削裂纹鉴别

分析磨削烧伤的基本特征,并通过显微组织和显微硬度的测定探讨磨削烧伤形成的机理,对四种不同鉴别磨削烧伤和磨削裂纹的方法进行研究。     

Experimental study of grinding fluids for abrasive-belt grinding of stainless steel

A number of ferritic stainless steels with high corrosion resistance have recently been developed, but these steels are known to be difficult to grind in coated abrasive-belt grinding operations. In order to formulate or select an optimum oil-based grinding fluid with which such stainless steels can be successfully ground, an optimum base oil was first experimentally selected, and then additives were evaluated for their effect in improving abrasive-belt grinding performance. A paraffinic mineral oil having a certain viscosity was found to be suitable for the base oil. Chemical grinding oil additives were found markedly effective in improving the abrasive-belt grinding performance for both 19Cr-2Mo ferritic stainless steel and SUS 304 austenitic steel, with those containing sulphur or chlorine being superior to those containing phosphorus, fatty acid or alcohol. Among all the additives tested, chemically active oils, such as sulphurized mineral oil, exhibited the best performance. Effects of chlorinated paraffins on the grinding performance could be perceived but were not so great as those of sulphur-series additives. The addition of TCP (tricresyl phosphate) to the grinding oil containing sulphur reduced metal removal in the case of 18Cr-2Mo ferritic stainless steel (SUS 444). In the case of SUS 430 ferritic stainless steel, however, TCP increased metal removal for a comparatively low sulphur concentration, but, above an optimum concentration of 0.4 wt% S, metal removal was reduced by TCP addition. A comparison of sulphur-series additives added to a sulphurized paraffinic mineral oil showed that nonyl polysulphide was superior to any other additives for improving the grinding performance in 19Cr-2Mo steel (SUS 444) and SUS 430. Excess addition of sulphurized fatty oil to a grinding fluid lowered the cutting ability of abrasive grains.     

套圈平面磨削方式的分析及应用

通过对几种套圈平面磨削方式的分析，阐述了各自的特点，并根据其特点提出了具体的应用办法。     

砂轮位置对成形磨齿齿廓偏差的补偿

为提高成形磨齿加工的精度,提出一种通过调整砂轮位置实现齿廓偏差补偿的方法.应用包络理论,建立已知砂轮轴向廓形和砂轮位置误差计算齿轮端面廓形的数学模型.通过数值研究发现,齿廓倾斜偏差与砂轮径向位置误差和切向位置误差成正比例关系而且满足叠加原理.应用这些规律,依据测量的齿廓偏差可以方便地计算出砂轮位置调整量.试验结果表明,该方法可以将齿廓倾斜偏差由7级精度(ISO1328-1:1997)提高到2级精度.     

Investigation on grinding temperature in ultrasonic vibration-assisted grinding of zirconia ceramics

The feasibility of ultrasonic vibration-assisted grinding (UVAG) in machining brittle materials, such as zirconia ceramics, has been preliminarily proved. The high temperature generated in grinding processes is a main factor responsible for thermal and surface/subsurface damage. However, there are few reports about grinding temperature for zirconia ceramics by UVAG. In this study, a grinding force model is used for the analysis of grinding temperature in UVAG based on kinematic principle of ultrasonic vibration and brittle material fracture removal mechanism. Then, the heat fluxes equation during grinding process is analyzed. And the grinding temperature model is developed based on theoretical grinding force model and heat fluxes. Finally, pilot experiments are carried out to analyze influence of vibration parameters and process parameters on UVAG temperature and verify the mathematical model. The comparison results show that ultrasonic vibration has an important influence on grinding temperature with the reduction of 10.6%. In addition, there is a good consistency between mathematical model and the experimental results. The average relative error is within 10%. Therefore, the mathematical model could be used to predict the UVAG temperature.     

21NiCrMo5H齿轮钢超声磨削力建模研究

磨削力的建模研究是认识超声磨削机理的重要基础。在超声磨削单颗磨粒运动特性分析基础上,基于工件上被切削掉的磨屑体积应等于砂轮磨削去除的体积的原则,推导出超声磨削平均未变形磨屑厚度公式,得到切屑变形力模型;考虑超声振动对摩擦因数的影响,建立磨粒与工件摩擦力模型。综合切屑变形力模型、摩擦力模型,推导出超声辅助磨削下的磨削力模型,进行21NiCrMo5H齿轮钢材料渗碳淬火后超声磨削试验研究,确定磨削力模型中相关材料系数,得到超声磨削力模型。与现有文献的计算模型相比较,给出的超声磨削力模型与磨削试验测量结果具有更好的一致性,并对超声磨削机理提出了新的认识,为后续研究提供更多的参考与基础。