Slot Grinding of Steels and Ceramics with Superabrasive Wheels

Slot grinding (a kind of creep feed grinding) was conducted on SKD-11 and S50C steels and alumina ceramic with different CBN and diamond grinding wheels, using a specially designed abrasive cut-off apparatus. The wheel speed ranged from 33 to 58m/s, where wheel size is 150mm dia. and 1.0mm or 3.0mm width. The maximum wheel depth of cut is 7.0mm and the maximum table speed is 50mm/min. The metal bond CBN wheels of different specifications were used for the slot grinding of steels, while the metal bond diamond wheels were used for the ceramic grinding. Thus, grinding forces were mainly studied under different wheels and operating conditions, and also stress distribution along contact arc, grinding temperature, and chipping of edge were discussed.     

Profiled Superabrasive Grinding Wheels for the Machining of a Nickel Based Superalloy

Machining data are presented for small diameter, profiled (fir tree root form), single layer/electroplated CBN (B46, B76 and 91) and diamond (D46) grinding wheels, when cutting Udimet 720. Spindles operating at 60,000 and 90,000 rpm were employed, with a synthetic polyalphaolefine (PAO) oil based fluid in a down grinding mode on single sided specimens. Operating parameters were selected to reflect finishing conditions. Measured tool wear was lower for CBN grit as compared to diamond however workpiece roughness was lower with Ra approaching 0.75 μm when using D46 wheels. Higher rotational speed produced lower grinding wheel wear. No workpiece burning was observed irrespective of grit type at the conditions tested.     

结构化超硬磨料砂轮设计与制备研究进展

从减摩降力、导屑促排、储液换热的角度出发,探索结构化砂轮在降低磨削力及磨削温度、抑制工件表面热损伤、提高工件加工表面完整性等方面的有效方法。以砂轮表面/基体结构的几何形状、三维尺寸及排布方式等因素对磨削性能的影响为主线,对结构化砂轮设计、制备的基本原理与最新进展进行了全面的论述和总结,重点揭示了结构表征参数-砂轮磨削性能-工件表面质量的内在关联,深入剖析了结构化砂轮在磨削中的优越性,并预测了其未来发展趋势,旨在为推进超硬磨料结构化砂轮的设计及制备技术发展提供理论指导和实践经验。     

陶瓷结合剂CBN砂轮磨削表面粗糙度的试验研究

本文通过一系列的试验，研究了陶瓷结合剂CBN砂轮磨削表面粗糙度的变化规律及其特点，建立了相应磨削表面粗糙度的经验公式。     

Surface Generation with Engineered Diamond Grinding Wheels: Insights from Simulation

Engineered wheels are a recent innovative development towards consistent and exceptional performance in fine grinding operations. Abrasive grains in an engineered wheel are positioned in a specific spatial pattern, as opposed to random locations in a conventional wheel. The present work relates to the formulation of a theoretical framework for the design of engineered wheels In terms of maximizing their performance with respect to their surface generation characteristics. Computer simulations Indicate that: (I) The distribution of abrasive protrusion height, rather than Its absolute maximum value, determines the roughness of the ground surface and controls the associated variability, and therefore by tailoring the distribution appropriately, the performance of the wheel can be improved significantly, (II) With an ordered arrangement of abrasive grains, the finish obtained is a strong function of the axial offset between adjacent rows of grains, but the best finish achieved thus is only on the order of that obtained with a conventional wheel, and (III) The effect of grain shape on the roughness of the ground surface is comparable to the Inherent process variability.     

超硬磨料砂轮修整与激光修整新进展

本文介绍了超硬磨料砂轮修整的现状和特点，指出超硬磨料砂轮修整的关键和亟待解决的问题。重点介绍一种很有前途的修整技术－－激光修整，分析了其国内外近年来的研究情况。作者用声光调QYAG激光对树脂结合剂CBN砂轮进行了修锐试验，得出了声光调QYAG激光适宜修锐树脂结合剂砂轮的结论。对今后的超硬磨料砂轮激光修整的发展方向作了展望；建立材料热去除模型和气体动力学模型，完善激光修整机理的研究；实现激光整形和修锐过程同时进行；深入研究激光精密修整技术；开发成形砂轮激光修整技术；开发自适应控制修整系统，实现激光在线修数；提高修整效率。     

表面放电辅助金刚石砂轮复合修整的可行性研究

针对金刚石砂轮修整困难的问题,提出了基于表面放电辅助的金刚石砂轮的复合修整法,并通过测量放电时的表面温度对该方法的可行性进行了研究,最后基于研究结果进一步提出了改进方案.     

An Investigation of Grinding with Electroplated CBN Wheels

Grinding of hardened bearing steel with electroplated CBN wheels was Investigated with particular attention to how the wear of the abrasive grains affects the wheel topography and grinding performance during the wheel ire. Power, surface roughness, and wheel topography data were obtained throughout the wheel life for internal cylindrical grinding. Dulling of CBN gratis by attrition was found to cause an increase in the grinding power, but the degree of dulling was restricted mainly by grain fracture and also by grain pullout. Grain fracture and pullout had a much smaller effect on the progressive increase in active grain density, which caused the surface roughness to progressively decrease. Wheel failure tended to occur by stripping of the abrasive layer when the radial wear reached about 70% - 60% of the grain dimension     

高速钢工件表面物理化学气相沉积TiN

介绍了等离子化学气相沉积氮化钛技术在高速钢刀具和飞机用高速钢精密轴承上的应用，经ＰＣＶＤ－ＴｉＮ处理的高速钢刀具可以提高其表面强度，降低摩擦系数，从而提高其使用寿命，处理过的高速钢轴承精度高，具有抗高温氧化和抗热震性能，满足了使用要求。     

Factors Affecting Grinding Performance with Electroplated CBN Wheels

An experimental investigation was conducted to evaluate the effect of CBN crystal characteristics and plating thickness on the performance of electroplated CBN wheels. Wheels containing tougher CBN crystals generally exhibited less wear and a higher G-ratio, and also required less power. Furthermore, contrary to expectations, less wear and higher G-ratio were also obtained for wheels with a thinner layer of nickel plating despite an increased tendency for large-scale crystal loss. This would indicate that the overall wheel wear depends more on crystal exposure than on active grain density, which could facilitate chip removal and grinding fluid access. Extended grinding tests up to wheel failure ascertain the improved grinding performance with tougher crystals and thinner electroplated layers.     

陶瓷结合剂CBN砂轮磨损与磨削比的研究

通过对国产陶瓷结合剂CBN砂轮磨削45淬硬钢的试验,研究了磨削参数对CBN砂轮磨损与磨削比的影响规律,获得了磨削参数的最优水平,并建立磨损与磨削比的经验公式,探讨了冷却液流量对磨损与磨削比的影响规律。     

自锐性金刚石树脂砂轮磨削性能的研究

本文通过对比磨削试验，研究了自锐性金刚石(CSD)树脂砂轮的磨削性能。试验结果表明，由于CSD形状小规则，有许多凹入角和粗糙表面，树脂结合剂对CSD的把持力较普通金刚石强，所以在磨削各参数相同的条件下，自锐性金刚石砂轮与普通金刚石砂轮相比，其磨削比提高60％以上。且由于CSD的内部为许多单个亚晶粒所组成的镶嵌的颗粒，因此在应力作用下，只有很小的不规则的碎片崩掉，从而在每个颗粒的表面上留下许多新的小切削刃，故其加工工件的表面粗糙度值较低。     

Development of a Superabrasive Grinding Wheel With Defined Grain Structure Using Kinematic Simulation

This paper presents the concept of superabrasive electroplated grinding wheels based on defined grain structures. The aim is to improve process stability, minimize heat generation and achieve a high surface quality while preserving a high material removal rate. Based on geometrical models, different patterns of grit settings have been investigated by means of kinematic simulation. Applying the results of the simulation, a prototype grinding wheel with an optimized defined grain structure has been constructed. The performance potential of the prototype has been analyzed through experimental examinations.     

薄壁零件的铣削加工稳定性研究

为控制薄壁结构零件加工过程中的变形和切削振动,在考虑刀具和工件两个方向的自由度的基础上,分析、建立了薄壁零件的动态铣削模型.针对2A12铝合金薄壁结构零件,利用Mikron高速加工中心和相关仪器,通过铣削力实验和模态实验,分别测得特定刀具和工件系统的动态铣削力系数和模态参数,从而绘制出高速铣削薄壁零件的稳定性叶瓣图,得到了不同径向切深条件下的极限轴向切深,并通过试验进行了验证.这种方法可用于相关薄壁零件加工时合理选择切削用量.     

不同结合剂金刚石砂轮在硬质合金刀片磨削中的性能对比

本文采用树脂结合剂金刚石砂轮与金属结合剂金刚石砂轮分别加工WC-10%Co硬质合金数控刀片,研究了这两种结合剂的金刚石砂轮对工件尺寸精度一致性、表面粗糙度和磨削比的影响。实验结果表明相对于树脂结合剂金刚石砂轮,金属结合剂金刚石砂轮磨削的工件能达到同等水平的尺寸一致性、具有更高的表面粗糙度值和更高的磨削比。在尺寸精度一致性、粗糙度达到工件技术要求的基础上,具有更高磨削比的金属结合剂金刚石砂轮磨削硬质合金刀片中具成本优势。