硬脆材料专用ELID磨削液的研制

本文在已有新型通用ELID磨削液(HDMY-20型)的基础上，根据硬脆材料的磨削特点和ELID磨削过程中磨削液的电解修锐生膜缓蚀作用、结合通用ELID磨削液的研制经验．通过增添表面活性剂、稳定剂、防锈剂、油性极压剂和调整无机盐等成分的比例关系．优化出适合硬脆材料ELID磨削最佳状态的专用ELID磨削液。应用此磨削液磨削硬质合金表面粗糙度可达Ra0．007μm比通用型磨削液磨削的硬质合金Ra值降低了0．005μm。     

W-Mo合金精密镜面加工工艺的实验研究

为了研究W-Mo合金材料精密加工的新途径,采用在线电解修整(ELID)精密磨削和超精密研抛技术,对其进行了精密镜面加工实验,分析了此材料超精密镜面表面的形成机理。通过ELID磨削加工得到了表面粗糙度Ra0.020μm加工表面,再以研抛压力为0.1~0.3 N/cm2,转速为60~100 r/min等优化研抛参数进行研抛加工,获得了表面粗糙度为Ra0.012μm精密镜面加工表面。实验表明:ELID精密磨削加工是保证工件表面质量的基础,超精密机械研抛时研抛压力及转速等参数对工件表面质量起主要影响作用。     

基于ELID磨削机理的GCr15轴承钢内圆工艺试验研究

针对GCr15轴承钢内圆传统磨削加工方式存在的精度低、烧伤及裂纹等缺陷,文章采用ELID精密镜面磨削技术对其进行工艺试验研究。在ELID精密镜面磨削机理及钝化膜数学模型的理论指导下,进行正交试验探究磨削深度、砂轮线速度、电解电压及占空比对表面粗糙度的影响及其最优参数组合,并采用极差法分析探究各因素对工件磨削质量影响程度的大小。研究结果表明在磨削深度0.5μm,砂轮线速度30m/s,电解电压50V,占空比50%的最佳工艺参数下可获得表面粗糙度为13nm的已加工表面     

SLM零件的磨粒流动辅助电化学复合抛光方法研究

针对增材制造金属零件表面质量较差的问题，提出一种磨粒流动辅助电化学复合抛光方法，在电解液中混入微小磨粒，使混合液在一定压力下流经工件表面，通过磨粒磨削和电化学溶解的复合作用改善工件表面质量。通过试验对比了纯磨粒磨削、纯电解加工和复合抛光的加工效果，分析了不同工艺参数对工件表面粗糙度和材料去除量的影响。试验结果表明：复合抛光方法能有效去除增材制造零件表面缺陷，改善其表面质量。通过选取合适的电压进行分阶段抛光，SLM工件的表面粗糙度由Ra8.162μm降至Ra1.226μm。     

硬质合金刀具材料的超精密磨削试验研究

本文引入了一种新型超精密镜面磨削方法——在线电解连续修整磨削(ELID磨削),介绍了该方法的机理和实现条件,并运用在线电解修整的金属结合剂超细磨粒超硬磨料砂轮,进行了硬质合金刀具材料YT14的超精密镜面磨削,取得了良好的结果,工件表面粗糙度直接可达十几个纳米。     

超声振动辅助ELID磨削淬硬12Cr2Ni4A合金钢表面特性的研究

目的 提高淬硬12Cr2Ni4A钢的加工质量,消除工件表面残余应力.方法 采用普通磨削(OG)、超声振动辅助磨削(UVAG)以及超声振动辅助ELID磨削(UVAEG)3种磨削方式,分别对淬硬12Cr2Ni4A合金钢进行加工,分析3种加工方式下被加工工件的表面粗糙度以及残余应力.结果 在超声振动辅助磨削、超声振动辅助ELID磨削下,工件表面粗糙度都低于普通加工,而超声振动辅助ELID磨削后的工件表面质量最高,相对普通磨削加工,超声振动辅助ELID磨削后的表面粗糙度降低了66％,相对于超声振动辅助磨削,超声振动辅助ELID磨削后,表面粗糙度降低了约41％.对工件表面进行残余应力测定发现,普通磨削加工后工件表面为残余拉应力,而超声振动辅助磨削、超声振动辅助ELID磨削后的工件表面都产生了残余压应力,超声振动辅助ELID磨削后,工件表面的残余压应力高于超声振动辅助磨削约30％.普通磨削加工中,随磨削深度的增加,残余拉应力一直变大,而超声振动辅助磨削和超声振动辅助ELID磨削的残余压应力总体呈现减小的趋势.在磨削深度达到22.5μm后,超声振动辅助磨削加工表面的残余压应力转变为残余拉应力.在超声振动辅助磨削和超声振动辅助ELID磨削后,随超声振幅的增大,表面残余压应力增大,超声振动辅助ELID磨削表面的残余压应力随占空比的增大而增大.结论 超声振动辅助ELID磨削加工后,能得到更小的表面粗糙度及更大的表面残余压应力.     

航天用SiCp/Al复合材料卫星输出轴精密磨削工艺研究

针对48%体积比SiCp/Al复合材料卫星专用输出轴的超精密加工难题,采用ELID精密磨削技术对其进行了工艺实验研究。首先,通过建立切入磨粒磨削模型,得到了48%体积比SiCp/Al复合材料的磨削机理及影响因素。然后探究了不同电火花参数对砂轮修整形貌的影响,并采用极差分析探究了各因素对工件磨削质量影响程度的大小。研究表明,当砂轮转速为1500r/min,进给量0.25μm,进给速度0.9m/min,电解电流10A,占空比60%时,磨削质量最好,得到了表面粗糙度Ra0.096μm,圆柱度0.85μm的48%体积比SiCp/Al复合材料输出轴精密磨削表面。     

航空铝合金高效精密电解铣磨加工试验

基于电化学溶解与机械磨削的复合作用对工件材料大余量去除的技术上,提出了针对航空铝合金的电解铣磨加工方法。试验研究表明:与电解铣削加工相比,电解铣磨加工可获得更高的加工速度,材料去除率从160.64 mm~3/min提升至192.58 mm~3/min,侧面平整度从434.1μm减至274.1μm,底面平整度从1154.1μm降至610.5μm。此外,在电解铣磨精密加工阶段后,侧面平整度的数值从274.1μm进一步降至77.4μm,表面粗糙度从Ra1.373μm减至Ra0.539μm。     

SLM成型零件型腔内表面电解辅助磁粒研磨加工研究

为了去除选区激光熔化技术成型的零件表面缺陷和降低表面粗糙度,并寻求最佳的加工参数。从理论上解析电解辅助磁粒研磨的加工机理,利用仿真软件模拟加工区域的磁感应强度分布,设计Box-Behnken试验方案,先对材料为Ti6Al4V的钛合金工件表面进行电解钝化,后进行机械磁粒研磨,根据试验结果建立表面粗糙度的二次响应回归方程并对建立的数学模型进行方差分析,最后用响应面分析法分析主轴转速、磨料粒径、电解温度和电解电压对表面粗糙度的影响规律,得到最佳的加工参数,在最佳工艺参数下对磁粒研磨和电解辅助磁粒研磨的加工效果进行比较和分析。建立的回归方程调整后的拟合优度为92.14%,经过优化后的电解辅助磁粒研磨最佳加工参数如下:电解液为浓度16%的硝酸钠溶液,电解温度28℃,电解电压12 V,磨料粒径180μm,主轴转速1 100 r/min,使用磁粒研磨加工60 min后,工件表面粗糙度由原始的Ra 10.7μm降为Ra 0.52μm,使用电解辅助磁粒研磨加工60 min后,工件表面粗糙度由原始的Ra10.7μm降为Ra 0.354μm。使用电解辅助磁粒研磨可以有效去除选区激光熔化技术成型零件型腔内表面的缺陷,并降低零件的表面粗糙度,通过响应面分析法可以有效优化加工参数,使用电解辅助磁粒研磨加工比单一磁粒研磨加工的加工效果好,加工效率高。     

修整参数对陶瓷cBN砂轮磨削效果的影响

本研究采用陶瓷cBN砂轮加工冷激合金铸铁凸轮,采用金刚石滚轮对砂轮进行在线修整。通过改变修整量、滚轮与砂轮的相对移动速度、修整速比,得出修整参数对砂轮磨削效果的影响规律。研究结果表明,当修整量从5μm×4降低到5μm×3时,工件表面粗糙度从0.25μm增大0.27μm,但仍可满足加工表面粗糙度要求,而砂轮修整量减少1/4,砂轮使用寿命延长;滚轮与砂轮的相对移动速度从0.1 mm/r增大到0.15 mm/r时,工件表面粗糙度值Ra从0.354μm上升到0.452μm,砂轮耐用度从750个工件降低到480个;修整速比增大,工件磨削表面粗糙度增大,当修整速比从0.61增大到1.35时,工件表面粗糙度值Ra从0.2μm增大到0.63μm。     

Surface finishing of Ni–Cr–B–Si composite coatings by precision grinding

A Ni–Cr–B–Si/10vol%WC coating material has been precision ground to an optical quality surface finish (<10 nm R_a) using a combination of a very stiff precision machine tool, Tetraform “C”, 76 μm CBN grinding wheels and electrolytic in-process dressing (ELID) assisted grinding. When grinding without ELID, surface finish has been shown to be limited by damage to primary and secondary carbides. This damage may be in the form of carbide pull-out or localised fracture and removal of the larger primary WC particulate. ELID assisted grinding helps maintain CBN grit protrusion and sharpness and thus promotes efficient cutting during grinding, minimising pull-out and localised damage to the harder phases within the coating microstructure. ELID therefore improves both the overall surface finish and surface integrity of the workpiece.     

ELID precision grinding of large special Schmidt plate for fibre multi-object spectrograph for 8.2 m Subaru telescope

To explore various scientific frontiers from nearby substellar objects to large scale structures of the high redshift universe, a Fibre Multi-Object Spectrograph (FMOS) is being developed as the second generation near-infrared measuring instrument for the prime focus of 8.2 m Subaru telescope in Hawaii, which employs a large special Schmidt plate element. The Schmidt plate consists of a large non-axisymmetric aspherical concave plate and a convex plate. This paper introduces its manufacturing process, focusing on its non-axisymmetric aspherical surface machining by utilizing synthetically ELID grinding and arc-enveloped grinding method. A new grinding system capable of fabricating large optical elements was developed with 10 nm resolution. In this ELID arc-enveloped grinding system, a Cast Iron Fibre Bonded (CIFB) diamond wheel was 3D controlled to scan the workpiece to generate required surface. Grinding characteristics such as attainable form accuracy, surface roughness were investigated. Furthermore, some measures to improve form accuracy were discussed and verified.     

钢结硬质合金在瓷粉料干压成型模具中的应用

分析了钢结硬质合金Gw50的热处理工艺,提出采用ELID精密镜面磨削技术代替原来的传统磨削工艺,对钢结硬质合金模具进行精密磨削,使其能够满足产品质量要求,并提高了劳动生产率.     

A study on ELID ultra precision grinding of optical glass with acoustic emission

ELID grinding of BK7 glass and Zerodur was investigated using acoustic emission. Experiments showed that the contacting area between the wheel and workpiece in a grinding process was critical to influence wheel loading for a fine grit size resin-bonded cup wheel. ELID can be used for efficient material removal when the wheel/workpiece contacting area is large. Correlations were observed between the dressing intensity on the ELID wheel and the detected AE signals. Aggressive ELID dressing parameters for grinding with finer grit size wheels corresponded to a lower AE level. With an increase in the processing time of an ELID wheel, low and stable AE amplitudes became large with fluctuations due to the deterioration of the grinding wheel. Results indicate that the AE sensing technique has the potential to be adopted as an effective method for monitoring an ultra precision grinding process, identifying the condition of the grinding wheel and investigating the mechanism of ELID grinding.     

超声振动辅助ELID复合内圆磨削系统中大负载变幅器的设计及应用

为解决超声振动辅助ELID复合内圆(UAEI)磨削陶瓷等硬脆材料的声学系统设计难题，对驱动几何尺寸大、质量重的金属结合剂金刚石砂轮用的小端较长的变幅器进行理论设计及优化。基于弹性波在介质中的传播规律，利用MATLAB确定变幅器取值方案，再根据加工要求并结合ANSYS模态分析筛选出符合要求的方案，然后采用零阶算法进一步优化处理，得到满足几何尺寸、应力及振动频率要求的变幅器尺寸。对设计出的变幅器进行振动特性测试，其谐振频率理论误差为0.192%～1.824%，符合预期设计要求。采用研制出的UAEI磨削系统进行加工特性测试，与在线电解修整砂轮(ELID)内圆磨削比较，其工件的表面粗糙度降低了44.2%，且工件三维形貌更加平整，砂轮表面状况获得改善。      

GCr15钢的ELID磨削性能实验研究

为了探讨GCr15钢的ELID（Electrolytic In-process Dressing）磨削性能，在基于大量实验的基础上，对GCr15钢采用ELID磨削时磨削力的变化规律进行了详细分析，并将磨削力、磨削表面粗糙度与普通磨削进行了比较。结果表明，采用铸铁结合剂CBN砂轮进行ELID磨削时磨削力几乎不随时间的变化而变化，而采用白刚玉砂轮进行磨削时的磨削力随时间的变化不断增大，在线电解修整使CBN砂轮在磨削过程中始终保持良好的磨削性能，有利于节省砂轮修整时间，提高加工效率。在ELID磨削中，采用微细砂轮进行磨削可以获得很低的表面粗糙度，实现对GCr15钢的超精密镜面磨削。     

陶瓷喷涂层精密镜面磨削技术的实验研究

在工件表面用喷涂方法形成陶瓷涂层,可以显著改善其性能。但是由于陶瓷喷涂层的硬脆特性,难以进行精密加工。本文引入金属基超硬磨料砂轮在线电解修整（ＥＬＩＤ）技术,对陶瓷喷涂层进行精密镜面磨削的实验研究。结果表明,该技术加工精度高、表面质量好,极具应用前景。     

A comparative study: surface characteristics of CVD-SiC ground with cast iron bond diamond wheel

Efficient precision machining of CVD-SiC (chemical vapor deposited silicon carbide) reflection mirrors in extremely low surface roughness and high form accuracy is greatly demanded by advanced industrial fields. The existing lapping methods have a great difficulty in satisfying these demands. Some researchers proposed ductile mode grinding technology, but it inevitably required a very expensive grinding machine, and its grinding process with such fine abrasive wheel was usually unstable. Dr. H. Ohmori put forward a new idea of application of ELID-grinding to ultraprecision grinding of CVD-SiC mirrors. The method had a potential to solve the above problem. In this paper, the precision grinding of CVD-SiC was performed by two kinds of methods. One is the ELID grinding; the other is the ordinary grinding with the saw-like-abrasive-stone-dressed cast iron bond diamond wheel. A comparative study of surface characteristics of ground CVD-SiC has been carried out. The following conclusions have been drawn below. (1) The surface characteristics of wheels dressed by these two methods are different. (2) The surface roughness ground by ELID grinding was only slightly better than the one produced by the ordinary grinding method. (3) The microscopic characteristics of CVD-SiC ground by these two methods differed largely. (4) ELID grinding is greatly recommendable in precision grinding of hard-brittle materials on ordinary machines of low rigidity.     

Precision internal grinding of bearing steel based on the state control of oxide layer with electrolytic in-process dressing

The oxide layer state directly relates to the grinding efficiency and machining quality in electrolytic in-process (ELID) grinding. However, no proper and detailed information has been found about internal grinding by controlling the state of the oxide layer. Therefore, in this investigation, some experiments have been conducted based on the active control of the oxide layer state to study internal grinding performance and ground surface qualities. The experimental comparison with the traditional ELID grinding has been carried out to prove the advantages of the proposed method in dynamic equilibrium. The influences of the grinding and electrical parameters on the workpiece surface quality, force characteristics and material removal rate of internal machining of bearing steel have been investigated in detail. The experimental results show that the new method can realize a stable internal grinding process even with finer abrasive wheels of W10 and W2.5.     

不同结合剂金刚石砂轮磨削氧化铝陶瓷工艺实验研究

本文利用树脂、青铜、铸铁三种结合剂金刚石砂轮,以氧化铝陶瓷为加工对象,通过研究各自的磨削比、磨削力、磨削表面粗糙度等指标,进行了三种结合剂砂轮的磨削性能比较,发现铸铁结合剂金刚石砂轮和ＥＬＩＤ（在线电解修整）磨削方法比较适合氧化铝陶瓷等硬脆材料的磨削（尤其是精密磨削）。