金属结合剂金刚石砂轮的修整研究(Ⅱ)——修整金属结合剂金刚石砂轮的机理

在上一篇文章中。笔者提出了一种新的测量磨粒突出高度的方法,并就磨粒突出高度同砂轮磨削性能的关系进行了研究。本文探讨了结合剂密实型金刚石砂轮的修整机理,着重讨论修整时磨粒周围结合剂的会除过程。证明了去除结合剂的机制是杯形砂轮上脱落下来的GC磨粒的研磨作用。主要结论如下:(1)修整时,GC磨粒从杯形砂轮上脱落并研磨结合剂,从而产生修整效果。因此,杯形砂轮修整器在对金属结合剂金刚石砂轮进行整形的同时,也对其进行修锐。(2)控制冷却液流量使GC砂轮表面附有一层游离磨粒,可以使修整比最高。(3)只要修整次数足够多,平均磨粒突出高度只取决于修整条件。(4)游离GC磨粒的尺寸越大,研磨作用越强,因此修整比越高,平均磨粉突出高度越大。     

陶瓷结合剂金刚石砂轮的修整研究(Ⅱ)——杯形砂轮修整器的修整性能

本文详细讨论了杯形砂轮修整器修整陶瓷结合剂金刚石砂轮时的性能。主要结果如下:(1)修整器以横向进给方式修整时,金刚石砂轮断面形状为一斜线。使用其它修整器时,只要以横向进给方式进行修整,所得断面形状亦为一斜线。(2)修整器以切入送进方式修整时,只要把修整器旋转轴线调整到垂直于工作台面,则金刚石砂轮断面形状为一水平直线。若把旋转轴线调整到同工作台面成非90°夹角,则断面形状为一圆弧线或者斜线。(3)以切入送进方式修整时,金刚石砂轮速度越低或工作台速度越高,修整比越高。杯形砂轮旋转速度对修整比没有明显影响。(4)金刚石砂轮速度过快容易使砂轮表面磨粒钝化。     

钎焊金刚石砂轮修整实验研究

单层钎焊金刚石砂轮的圆度轮廓精度由于受磨料粒径和钎焊结合剂层高度不均匀等因素的影响而使其难以在工程陶瓷等硬脆材料精密磨削中应用.然而单层钎焊金刚石砂轮的修整是直接对金刚石磨粒进行微量的磨损,修整难度大、效率低,因此,探讨快捷且精密的整形方法就成了解决其应用问题的关键技术之一.在本文研究中,分别采用铁基金刚石烧结磨块、钎焊细粒度金刚石板和氧化铝磨块三种整形工具对钎焊金刚石砂轮进行了磨削法整形实验研究,实验结果表明利用氧化铝磨块进行磨削修整效率极低;钎焊金刚石板磨削修整虽然效率高,但是对砂轮表面金刚石磨粒造成大量破碎磨损;铁基金刚石烧结磨块在整形过程中可稳定地以磨平方式磨损砂轮表面金刚石磨粒,经精密整形后的砂轮圆度轮廓精度较高,用其磨削工程陶瓷时工件表面的犁沟和裂纹明显减少.     

GC杯形砂轮修整碟形金刚石砂轮实验研究

本文对GC杯形砂轮修整树脂结合剂碟形金刚石砂轮进行了实验研究，实践了一种新的端面修整方式。实验从磨削几何学的角度研究了杯形砂轮端面修整金刚石砂轮端面的影响，分析了端面磨削时接触弧长的特点；对不同主轴转速、砂轮参数、进给速度几方面做了对比试验，结果表明：GC杯形砂轮对超硬磨料砂轮有良好的修整作用，并以脱落的GC磨粒对结合剂桥的冲击与研磨为主要方式；修整效率决定于GC粒度、主轴转速，在粗粒度、中等转速下修整效率最高，进给速度对修整效率影响不大；在磨削过程中，应根据其他参数的变化调节GC砂轮与金刚石砂轮的中心偏移量H，偏移量小，修整效率高。     

金属结合剂金刚石砂轮的修整研究(Ⅲ)——修整后结合剂形态对磨粒把持情况及砂轮磨削性能的影响

用杯形砂轮修整器整形和修锐结合剂密实型金刚石砂轮时,笔者发现在磨粒后方存在一部分结合剂残留物,并把它称之为结合剂三角洲。本文首先描述结合剂三角洲形成机理及其特性,然后讨论它对砂轮摩削性能的影响。主要结论如下:(1)结合剂三角洲形成在杯形砂轮和金刚石砂轮速度矢量差之方向(修整方向),当修整方向同磨削方向不一致时,它在磨削过程中可能和工件发生接触。(2)用杯形砂轮的两边交替进行修整,不仅可以保证结合剂三角洲的方向同磨削方向一致,并且还可以通过调整金刚石砂轮同杯形砂轮的速度比来控制结合剂三角洲的后背角φ。(3)结合剂三角洲越大,对金刚石磨粒的把持力也越大,使得修整后磨粒突出高度增大。(4)结合剂三角洲纵截面积增大会降低砂轮最外表层上的切削刃密度并使磨削力增加率减小。     

陶瓷结合剂金刚石砂轮的修整研究(Ⅰ)——各种修整方法的修整效果比较

金刚石砂轮欲获得满意的磨削效果必须进行适当的修整。目前一些常用的金刚石砂轮修整方法中,单点式金刚石修整笔和聚晶金刚石修整笔有较高的修整效率,但所修金刚石砂轮的磨削性能难以令人满意,SEM观察表明,此时砂轮表面的磨粒顶端大都被修平。制动式修整器所修金刚石砂轮的磨削性能好,但砂轮的不圆度仍有2～3μm,为了改进修整效果,本文提出了一种使用GC杯形砂轮的修整方法和装置。实验证明,此方法在修整效果和效率方面效果良好。     

陶瓷CBN砂轮的修整对磨粒分布状态和磨削效果的影响

陶瓷ＣＢＮ砂轮的修整对磨粒分布状态和磨削效果的影响４５０００７机械部郑州磨料磨具磨削研究所崔恒泰，夏悦，邱丽花，刘一来陶瓷结合剂ＣＢＮ砂轮具有气孔，易于修整，因此普遍认为只需采用金刚石笔像对普通磨料陶瓷砂轮那样进行修整即可，也有一些学者认为修整后再用...     

W-Mo-Cr合金对金刚石砂轮磨块的摩擦化学修整

为解决粗磨粒金刚石砂轮磨块的修整问题,使用W-Mo-Cr合金材料作为修整工具对磨粒粒度尺寸为297~420μm的金刚石砂轮磨块进行修整,修整前后分别测量砂轮表面磨粒的等高性和磨粒的微观形貌,并且分别用修整前后的砂轮磨块进行WC硬质合金的磨削试验。结果表明:W-Mo-Cr合金材料对金刚石砂轮修整效率高,修整后砂轮表面磨粒的等高性提升了60%左右。利用修整后的金刚石砂轮磨削WC硬质合金,工件表面质量得到很大的改善,表面粗糙度达到R_a0.149μm。      

D杯形砂轮修整碟形金刚石砂轮试验研究

本文采用了D杯形砂轮与碟形砂轮对磨法来修整大直径树脂结合剂碟形金刚石砂轮。在分析研究杯形砂轮修整碟形砂轮的修整原理及修整方式的基础上，用自行研制的专用修整装置，从主轴转速、修整深度、修整工具结合剂类型等方面进行了对比工艺试验研究，总结了杯形砂轮修整碟形砂轮的不同工艺参数与修整效率、修整质量之间的工艺规律。试验结果表明，在本试验条件下主轴转速500r／min，修整深度0．02mm的修整效率较好；细粒度、中等浓度的青铜结合剂杯形金刚石砂轮与粗粒度、高浓度的杯形砂轮修整碟形砂轮相比，后者具有较好的修形效果和修整效率；D杯形砂轮与GC杯形砂轮交替配合使用可以大大提高碟形金刚石砂轮的修形效率和修锐效果。     

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。     

先进光学磨削中杯形修整技术开发及应用

对于金刚石砂轮修整,尤其是有高精度要求的圆弧金刚石砂轮,杯形砂轮修整技术可以获得较好的砂轮磨削性能以及修整效率。本文开发了配套超精密平面磨床使用的杯形修整器,分析了其机械误差影响,并完成了修整实验及砂轮表面测量及半径拟合处理,从宏观上考察了该修整器对砂轮磨削性能的提高,结果证明该修整器可以进行有效修整,提高了加工工具精度,能满足金刚石砂轮修整使用要求。     

金刚石砂轮V形尖端的数控对磨微细修整技术

针对金刚石砂轮V形尖端的微细修整困难的问题,开发出一种对磨成型的V形尖端修整技术。在数控修整中,砂轮作V形的直线插补运动与修整工具对磨,逐渐被修整成V形尖端。本实验中修整工具分别是#600和#180绿碳化硅(GC)油石,砂轮分别为SD 400和SD 600金刚石砂轮。实验结果表明,较细粒度的修整工具不仅可以将砂轮V形尖端修整出更小的圆弧半径,而且也能够将微小磨粒修锐得更锋利,从而使加工的单晶硅微沟槽形状更加整齐。此外,采用修整后的圆弧半径小于20μm的SD 600金刚石砂轮V形尖端可以实现光纤石英微阵列沟槽的微细加工,也可以在SiC陶瓷和WC合金基板上加工出微锥塔阵列空间的功能表面。因此,数控对磨在位修整的工艺可以用于金刚石砂轮V形尖端的微细修整,实现硬脆性基板的微细磨削加工。     

A novel laser-assisted truing and dressing technique for vitrified CBN wheels

The preparation of vitrified CBN or diamond wheels by truing and dressing has a large influence on the grinding performance. A worn diamond dresser cannot produce sufficient protrusion of cutting grain edges. To reduce the wear of diamond dressers and hence guarantee a desired wheel surface, a novel truing and dressing method, namely, laser-assisted truing and dressing, is proposed and tested to achieve good dressing quality and efficiency. A systematical experimental feasibility study on this newly proposed laser-assisted truing and dressing technique is conducted by investigating truing efficiency, truing accuracy, dresser wear, dressed wheel profiles, and specific forces in comparison with those of the conventional single diamond methods. Experimental results show that the new laser-assisted truing and dressing technique offers a number of advantages over the conventional single-tip diamond dressing and truing method. In addition, the underlying mechanism of the laser truing and dressing process is investigated through the careful analysis of the properties of chips and the microscopic structural characteristics of wheels.     

Wire electrical discharge machining of metal bond diamond wheels for ceramic grinding

The application of cylindrical wire Electrical Discharge Machining (EDM) for profile truing of metal bond diamond wheels is presented. Instead of using the mechanical force to break the diamond and matrix in the grinding wheel, the wire EDM process uses the thermal energy or electrical sparks between the wire and rotating grinding wheel to remove the metal bond and form the wheel. The design and manufacture of a corrosion-resistant, precise spindle with the high-electrical current capability for wire EDM truing of grinding wheel is first introduced. Three truing configurations were designed to study effects of wire EDM process parameters and to investigate the level of form accuracy and corner radii achievable by the wire EDM truing of diamond wheels. Results show that the wire EDM process can efficiently generate the μm-scale precision form on the diamond wheels. The wheel, after truing, was used to grind the silicon nitride workpiece. Grinding forces and wheel wear rate were measured. In the beginning of the grinding, high wheel wear rate was identified. The subsequent wheel wear rate was considerably lower and stabilized.     

Computer simulation of sub-micron-scale precision truing of a metal-bonded diamond grinding wheel

A new simulation mode of wheel profile generation was proposed in precision truing of a metal-bonded diamond grinding wheel by considering the mutual wear of grinding wheel and truer in sub-micron scale. The aim is to understand how truing parameters influence truing accuracy and truing efficiency, namely wheel profile flatness and truing number. In order to assure the sub-micron-scale accuracy of a trued wheel profile, dry electro-contact discharge was employed in arc envelope truing. First, an arc-shaped truing profile replicated on wheel profile was defined and analyzed theoretically and then identified by truing experiment; second, the micro-truing ratio describing the mutual wear of a grinding wheel and truer related to the depth of cut was investigated by micro-truing experiment; then the simulation mode of the truing grinding wheel was established by using dispersed profile coordinates of the grinding wheel and truer with reference to the micro-truing ratio; finally, simulation analysis was conducted to trace on-line formation of the trued wheel profile in truing process. It is confirmed that this simulation method is valid and applicable to visualize the sub-micron-scale truing process. It is also found that by decreasing the depth of cut or plunge truing number wheel profile flatness decreases but truing number increases. It is concluded that there exist minimum wheel profile flatness and minimum truing number in a truing process, which can be used to optimize truing parameters for efficient precision truing.     

Application of rare- earth and nano elements on diamond cup wheels

Diamond cup wheel is used widely as an important tool for machining ceramic tile. In this paper, nano rare - earth oxide and nano carbide were added in the segments of seven kinds of diamond cup wheels. The performance of diamond cup wheels were tested on a special designed test machine by grinding two kinds of ceramic tiles. The surface morphology of the segments was examined by Scanning Election Microscopy （SEM） and the micro-hardness of segments was measured. The results showed that nano rare-earth oxide and nano carbide can fine segment micro structure, make grain boundary clear and increase grasping of diamond grits. They can increase also the wear resistance of diamond cup wheels as well as the grinding ratio.     

Comparison between vitrified bond and resin bond diamond grinding wheel in grinding PDC

In this research, the advantages and disadvantages of the cylindrical grinding process of Polycrystalline Diamond Compacts (short for PDC) with vitrified and resin bond diamond grinding wheel are compared. The research results show that the vitrified bond diamond grinding wheels, which use Ti-coated diamond grains as abrasive and glass ceramic as bond, have many advantages in grinding PDC . Compared with resin diamond grinding wheel,vitrified bond wheels lead to 35% grinding cost reduced, 40% grinding time of each PDC saved, and the size precision of PDC improved (from ±0.03mm to ±0.01mm). When grinding feed is ＜0.10 mm, the grinding ratio increases with increased grinding feed. However, when the grinding feed exceeds 0.10 mm, the grinding radio decreases rapidly with the increasing of grinding feed. The disadvantage of this kind of grinding wheel is that the brightness of the ground PDC cylinder is not as shining as that processed by resin bond diamond grinding wheel.