碟轮修整单层钎焊金刚石砂轮的试验研究

单层钎焊金刚石砂轮在制作完成之初由于砂轮基体加工存在误差以及磨粒粒径大小不一等原因造成磨粒等高性不一致,这使其难以在硬脆材料的精密磨削中得到广泛的应用。采用自制的钎焊碟轮对80/100#单层钎焊金刚石砂轮进行了修整试验研究。在修整试验前后跟踪了砂轮磨粒等高性的变化,进行了SiC陶瓷的磨削试验,并观测了工件表面质量的变化情况。试验结果表明:采用此方法能够实现单层钎焊金刚石砂轮的高效精密修整。修整试验结束后砂轮磨粒等高性较好,磨削SiC陶瓷的表面质量得到明显改善,表面粗糙度Ra值达到了0.1μm以下。     

单层钎焊金刚石砂轮的机械化学修整

单层钎焊金刚石砂轮的应用因其磨粒等高性不一致而在硬脆材料的精密加工中受到一定限制。本文采用机械化学复合法对80/100单层钎焊金刚石砂轮进行了修整试验研究。在修整实验前后,测量了砂轮工作面圆跳动,跟踪了磨粒的形貌变化,进行了砂轮磨削K9玻璃实验,观察并分析了工件磨削后的粗糙度值的变化。研究结果表明：机械化学复合法对单层钎焊金刚石砂轮的修整是有效的,磨粒的磨损以化学腐蚀为主,砂轮修整后磨粒等高性较好,磨削K9玻璃工件表面粗糙度明显降低。     

钎焊砂轮精密磨削K9玻璃的实验研究

K9玻璃广泛应用于高端光学元件,但K9玻璃是具有难加工性质的脆性材料。为了提高磨削效率,尽量减少磨削损伤以及减轻后加工工序的难度,降低加工成本,许多研究者都在开展K9玻璃的加工技术研究。钎焊砂轮具有磨粒出露高度大、磨粒易排序等特点,采用钎焊金刚石砂轮对K9玻璃进行精密磨削,研究砂轮在修整过程中的变化,并观察K9磨削表面质量随磨削工艺参数的变化。实验结果表明:砂轮修整时磨粒会出现平台磨损、棱边钝化等形态变化,磨削K9玻璃表面会出现有磨痕纹理的光泽区域和剥落破碎的坑点。     

钎焊金刚石砂轮高速磨削氧化铝陶瓷的磨损特征

利用真空炉中钎焊工艺制作了钎焊金刚石砂轮,并对氧化铝陶瓷进行高速磨削的磨损研究.实验中,监测了磨削过程中每道磨削的磨削力特征,观察和统计了不同磨削阶段的砂轮表面磨粒磨损状态及变化情况,同时测量了磨粒的出刃高度.结果表明:在高的砂轮线速度和高的材料磨除率下,容易造成大量的磨粒断裂和完全破碎.仅有1.23％的金刚石磨粒是经历“完整-磨平—微破碎—半破碎—断裂(全破)”的失效过程,即磨粒理想的失效路径.通过对钎焊工艺、磨粒承受的载荷以及砂轮表面磨粒浓度和排布方式等因素的分析,阐明了文中钎焊金刚石砂轮中磨粒失效的原因.     

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。      

粗磨粒金刚石砂轮精密磨削工程陶瓷的试验研究

为了实现粗磨粒金刚石砂轮延性域磨削加工SiC陶瓷材料,采用碟轮对粒径为297~420μm的粗磨粒金刚石砂轮进行了精密修整。然后,使用经过修整好的粗磨粒金刚石砂轮对SiC陶瓷进行磨削加工。在此基础上,对不同的砂轮线速度、工件进给速度、磨削切深对SiC陶瓷表面粗糙度和表面形貌的影响进行了研究。试验结果表明:经过精密修整的粗磨粒金刚石砂轮是能够实现SiC陶瓷材料的延性域磨削的,表面粗糙度值Ra达到0.151μm;随着砂轮线速度增大、工件进给速度和磨削切深减小,SiC陶瓷表面的脆性断裂减小,塑性去除增加。     

电镀金刚石砂端磨氧化铝陶瓷的机理研究

本文利用电子扫描电镜,观察了金刚石磨粒的微切削刃以及氧化铝陶瓷试件的磨削表面,已磨表面,对电镀金刚石砂轮端磨氧化铝陶瓷的机理进行了研究,指出氧化铝陶瓷已磨表面的缺陷以脆性裂纹为主,磨削温材料去除过程影响很大,有可能存在非裂主展的陶瓷去除方式。     

钎焊金刚石砂轮打磨钢轨的性能试验研究

针对树脂砂轮打磨钢轨时存在的火花大、粉尘污染等缺点，设计并制作钢轨打磨用单层钎焊金刚石砂轮。通过钎焊金刚石砂轮和树脂砂轮的钢轨打磨试验对比，对钎焊金刚石砂轮的综合性能进行评价。试验结果表明:在稳定打磨阶段，相比树脂砂轮，钎焊金刚石砂轮的磨削效率高、磨削电流小、磨削火花小，打磨后的工件表面粗糙度好；钎焊金刚石砂轮的主要失效原因是磨屑黏附。      

单层钎焊金刚石砂轮修整技术研究进展

对目前适用于单层钎焊金刚石砂轮的修整方法及其最新研究进展进行综述,指出各种修整方法在实际应用中所面临的问题。针对这些问题,提出单层钎焊金刚石砂轮修整技术的改进方法,为解决单层钎焊金刚石砂轮精密、高效、无损伤修整难题提供参考。      

钎焊金刚石砂轮磨削硬质合金温度的试验研究

根据半人工热电偶测温原理制备了磨削测温试样,利用感应钎焊金刚石砂轮和电镀金刚石砂轮进行硬质合金YG6的磨削试验,研究了磨削深度、工件进给速度对工件表面磨削温度的影响。试验结果表明:在相同的磨削参数下感应钎焊金刚石砂轮的磨削温度要远低于电镀金刚石砂轮,且随着磨削深度和工件进给速度的增大磨削温度上升较为平缓,钎焊金刚石砂轮磨粒出露高度高、容屑空间大,磨粒呈有序排布是磨削温度较低的主要原因。     

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.     

Precision grinding of structured ceramic molds by diamond wheel trued with alloy metal

Needs of micro structured components and its molds/dies are increasing in a solar cell system, an infrared night view and micro medical devices. In order to improve the accuracy of the structured molds/dies made of tungsten carbide, a new truing method of the diamond grinding wheel by alloy metals was proposed and the performance of the proposed truing method was evaluated. In the grinding test, Fresnel molds of tungsten carbide were ground by using the diamond wheel trued with the alloy metal. From the experiments it was clear that the form accuracy and surface roughness of the ground molds were improved.     

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。     

An experimental investigation of rotary diamond truing and dressing of vitreous bond wheels for ceramic grinding

Experiments of rotary diamond truing and dressing of vitreous bond grinding wheels were conducted to investigate the effects of feed, speed ratio, and overlap ratio on cylindrical grinding of zirconia. The applications of ceramic engine components with complex and precise form and the lack of technology for precision truing of diamond grinding wheels have driven the need to study the use of vitreous bond CBN and SiC wheels for form grinding of ceramics. Truing and grinding forces and the roundness and surface finish of ground zirconia parts were measured. By varying truing process parameters, a wide range of surface finish and roundness could be achieved. Experimental results showed that wheels trued at speed ratio below −1.0 could grind parts with fine surface finish and good roundness. The analysis of truing and grinding results showed the trend of increasing grinding force at higher specific truing energy and better surface finish at higher grinding force. The lack of speed control of the direct–drive, variable–speed truing spindle was observed and its effect on the reverse of direction of truing force at positive speed ratios was studied.     

CBN砂轮整形工具的优选

本文以试验为依据,系统地分析、比较了各种金刚石修整工具整形CBN磨具效果及整形后磨具表面地形状态,以此对CBN磨具整形工具进行优选,提出了以旋转型金刚石工具整形CBN磨具的优选工艺。     

金刚石砂轮的ECD修锐和整形研磨及其对硬脆材料的加工

为研究金属结合剂金刚石砂轮切削刃修锐整形对硬脆材料加工表面形态的影响,先通过接触放电法对SD600金属结合剂砂轮切削刃进行修锐,再用整形研磨方法对砂轮表面金刚石磨粒的不同切削刃高度进行整形研磨,最后用修整好的砂轮磨削加工用于光学设备的硼硅玻璃、石英玻璃、石英晶体和蓝宝石等几种硬脆材料。结果表明:硬脆材料粗糙度的改善程度取决于材料的种类,硼硅玻璃、石英玻璃、石英晶体、蓝宝石的最大粗糙度R_y比砂轮整形前的分别减少了44%、34%、30%、26%,且石英晶体材料几乎可以实现延性磨削。      

微粉金刚石钎焊砂轮磨削氧化铝陶瓷的磨削力和表面粗糙度特征

在不同磨削深度、砂轮转速和进给速度组合下,研究微粉金刚石钎焊砂轮磨削氧化铝陶瓷过程的磨削力及工件的表面粗糙度的变化规律,并筛选出低磨削力和低工件表面粗糙度的加工工艺参数。试验结果表明:在微粉金刚石钎焊砂轮的磨削过程中,氧化铝陶瓷主要通过脆性断裂的方式去除;随着磨削深度、进给速度的增加,砂轮在进给方向和切深方向的力以及工件表面粗糙度都上升;随着砂轮转速的增加,进给方向和切深方向的力以及工件表面粗糙度都下降。试验获得的低磨削力和低工件表面粗糙度精密加工工艺参数分别为:磨削深度为1.0 μm,进给速度为12 mm/min,砂轮转速为24 000 r/min和磨削深度为1.0 μm,进给速度为1 mm/min,砂轮转速为20 000 r/min。低磨削力磨削时,微粉金刚石钎焊砂轮受到的X方向和Z方向的磨削力分别为0.15 N和0.72 N;精密加工后的氧化铝陶瓷的表面粗糙度值可达0.438 μm。      

On-machine dry electric discharge truing of diamond wheels for micro-structured surfaces grinding

Precision grinding with diamond wheels gives a promising alternative to achieve high quality micro-structured surfaces on optical molds. However, it is difficult to true these diamond wheels efficiently, because of the remarkable resistance property and the geometrical limitation of small wheel profile. In this paper, an on-machine dry-EDT method to precision shape and prepare diamond wheels with various profiles was proposed for micro-structured surface grinding. Firstly, the fundamental truing errors were analyzed based on the dry-EDT kinematics. And then the capabilities of dry-EDT truing for high abrasive concentration metal bonded diamond wheels were presented. Next, the effects of kinematic parameters variables on trued wheel profile accuracy were investigated. Finally, the micro-structured surfaces on SiC ceramic and tungsten carbide WC were ground by these trued diamond wheels. The experiments results showed that the arc-shaped diamond wheel (diameter of 200 mm) with 4 μm profile error (PV) and 1.0023 mm profile radius, and the V-shaped diamond wheel with 22.5 μm V-tip radius and 120.03° profile angle could be obtained by on-machine dry EDT. The kinematic parameters of dry-EDT have an important influence on truing profile accuracy of diamond wheels, especially for the tip of V-shaped wheel. The subsequent grinding show that the edge radius of V groove array on SiC is less than 2 μm, while the radius of included corner is around 55 μm. The PV error of ground arc groove array on WC is less than 5 μm. The surface roughness of ground micro-structured surface R_a is 142 nm and 97 nm for SiC and WC, respectively.