石英玻璃的化学机械磨削加工

为了实现石英玻璃基板的高效、高质量加工,进一步改善光掩模设备的性能,进行了石英玻璃化学机械磨削(CMG)加工技术的研究。通过在磨削过程中主动增强磨粒、结合剂以及磨削液与工件的化学反应,并使化学反应与机械去除作用形成动态平衡,从而消除因材料脆性去除而造成的表面损伤等,实现了大口径玻璃工件的高表面质量、高形状精度的加工。针对石英玻璃CMG加工的特点,开发了CMG专用砂轮及磨削液,利用正交实验法优化了石英玻璃CMG加工工艺参数,分析了CMG加工过程中磨削压力、砂轮转速、磨削液流量、pH值等因素对加工表面粗糙度及加工效率的影响,并利用优化后的工艺参数加工得到了Ra为0.795nm的石英玻璃表面。加工后基板的光学性能和化学机械抛光(CMP)加工基板的光学性能相同,能够满足光掩模设备的性能需求。     

Development of binder-free CMG abrasive pellet and finishing performance on mono-crystal sapphire

Chemo-mechanical-grinding (CMG) is a fixed abrasive process by integrating chemical reaction and mechanical grinding for sapphire wafer finishing, and shows advantages in surface integrity, geometric controllability and waste disposal. However, the material removal rate (MRR) obtained by the traditional CMG wheel is not high enough to meet the requirement from the mass production of sapphire wafers. As a potential solution, a new CMG wheel with extremely high abrasive concentration has been proposed. This paper targets on developing of binder-free abrasive pellets (BAP) with 100 wt% abrasive as well as investigating the performance of BAP in sapphire wafer finishing. The results of CMG experiment reveal that the MRR and surface roughness (Ra) of sapphire wafer finished by BAP constructed CMG wheel are able to reach 1.311 μm/h and 0.993 nm respectively. The characterization by Raman microscope indicates that the finished sapphire wafer also owns excellent subsurface integrity.     

在线电解修整磨削与化学机械抛光相结合的蓝宝石基片组合加工技术

通过分析ELID磨削和CMP抛光两种加工技术的原理和特点,充分结合两种技术的优点,对蓝宝石基片进行超光滑纳米级精度的组合加工。从理论上分析和计算了蓝宝石的临界切削深度,以及在不同粒度砂轮下的脆性和延性磨削方式;采用不同粒度的砂轮对蓝宝石基片进行超精密ELID磨削实验,快速地获得高质量的加工表面,同时采用磁流变斑点法对加工面的亚表面损伤进行测量;利用CMP抛光技术对磨削加工后的表面进行光整,以减少磨削时产生的加工缺陷,使工件的表面质量得到进一步改善与提高,最终获得亚纳米级的表面粗糙度。     

外圆表面磁性研磨加工的研究

以加工外圆表面为例，分析对影响磁性研磨这一种新的表面光整加工工艺中的和种工艺参数进行佤分析，探求外圆表面磁性研磨加工的最佳工艺参数。     

Chemo-mechanical grinding by applying grain boundary cohesion fixed abrasive for monocrystal sapphire

This paper presents a novel fixed abrasive tool namely grain boundary cohesion fixed abrasive pellet (GBCFAP) which is able to provide higher finishing efficiency as well as better surface/subsurface quality of sapphire substrate during the chemo-mechanical grinding (CMG) process. The manufacturing procedures of GBCFAP are introduced in detail in this paper. It is found that the sintering temperature plays an important role to the strength of GBCFAP, and the strength of GBFCAP could be flexibly adjusted by sintering temperature. The experiment result suggests that the recommended sintering temperature ranges from 600 to 650 °C according to current CMG conditions. Meanwhile, comparing with conventional resin bound CMG wheel, 600 °C sintered GBCFAP CMG wheel performs better in terms of material removal rate and surface/subsurface quality since the chemical effect and mechanical effect during CMG process are well balanced. Meanwhile, the solid phase reaction between sapphire and Cr₂O₃ abrasive is demonstrated by TEM observation and XPS quantification.     

微细游离磨粒借助流体动压力实现的超精密加工技术

精密加工是先进制造方法的重要组成部分，利用微细游离磨粒进行陶瓷、玻璃、半导体等光学零件的超精密加工，不仅可获得高的表面质量，微米级的形状精度和纳米级表面粗糙度值，而且还可得到无加工变质层超精密加工表面。这里主要论述了流体动压力实现的条件及动压浮起平面研磨、浮动抛光、弹性发射加工以及砂轮约束磨粒喷射加工等微细磨粒借助于流体动压力实现超精密加工技术。     

硅片低损伤磨削砂轮及其磨削性能

针对传统金刚石砂轮磨削硅片存在的表面/亚表面损伤问题,研制了一种用于硅片化学机械磨削加工的新型常温固化结合剂软磨料砂轮。根据化学机械磨削加工原理和单晶硅的材料特性,设计的软磨料砂轮以氧化铈为磨料,二氧化硅为添加剂,氯氧镁为结合剂。研究了软磨料砂轮的制备工艺,分析了软磨料砂轮的微观组织结构和成分。通过测量加工硅片的表面粗糙度、表面微观形貌和表面/亚表面损伤,进一步研究了软磨料砂轮的磨削性能。最后,与同粒度金刚石砂轮磨削和化学机械抛光(CMP)加工的硅片进行了对比分析。结果表明,采用软磨料砂轮磨削的硅片其表面粗糙度Ra1nm,亚表面损伤仅为深度30nm的非晶层,远好于金刚石砂轮磨削硅片,接近于CMP的加工水平,实现了硅片的低损伤磨削加工。     

ABRASIVE-BASED NANO-FINISHING TECHNIQUES: AN OVERVIEW

The surface finishing techniques can be divided into two categories: traditional and advanced. To overcome some of the problems of traditional finishing techniques, hybridized processes have been evolved by the researchers. Some of the advanced finishing processes that have been reviewed are abrasive flow machining (AFM), magnetorheological finishing (MRF), magnetorheological abrasive flow finishing (MRAFF), magnetic abrasive finishing (MAF), chemo mechanical polishing (CMP), etc. Most of these processes have been developed in the recent past and they can be employed to produce optical, mechanical, and electronic components with micrometer or sub-micrometer form accuracy and surface roughness within nanometer range with hardly any surface defects. However for large size flat components, MAF seems to be the most suitable finishing process. In MAF, DC power supply is given to the electromagnet hence intermixing of ferromagnetic abrasive particles during the process does not take place and the worn out cutting edges keep interacting with the workpiece surface. As a result, the finishing rate is quite low. The use of pulsed DC power supply to the electromagnet results in pulsating flexible magnetic abrasive brush (P-FMAB), which substantially enhances the finishing rate. The on-line measurement of the forces has helped in understanding the mechanism of material removal during Static-FMAB (S-FMAB) and Pulsating-FMAB. The magnitude of normal magnetic force (originating indentations) in P-FMAB has been found to be dynamic in nature and substantially high in magnitude as compared to S-FMAB.     

超精密加工现状综述

超精密加工是获得高形状精度、表面精度和表面完整性的必要手段.精密光学、机械、电子系统中所用的先进陶瓷或光学玻璃元件通常需要非常高的形状精度和表面精度(如0.1 nm级表面粗糙度)及较小的加工变质层.掌握超精密加工过程中材料去除规律和损伤层特性对提高加工的稳定性与经济性十分重要.对超精密加工中的超精密切削、超精密磨削和超精密研磨抛光技术进行综述,重点介绍各种典型加工方法及其材料去除机理.从加工精度和加工效率角度对上述几类超精密加工方法进行比较,介绍以实现高效精密加工为目的的半固着磨粒加工技术.对超精密加工的发展趋势进行预测.     

A review on the progress towards improvement in surface integrity of Inconel 718 under high pressure and flood cooling conditions

Self-conditioning performance of polishing pad is an important characteristic to influence processing efficiency and service life in chemical mechanical polishing (CMP). The slurry can react with the pad surface, which affects its self-conditioning performance in fixed abrasive polishing process. Wear ratio of wafer material removal rate (MRR) and pad wear rate is introduced to evaluate self-conditioning performance of fixed abrasive pad (FAP). To clear the effect of chemical additive on FAP self-conditioning, wear ratio, FAP surface topography, friction coefficient, and acoustic emission signal of polishing process were investigated in fixed abrasive polishing of quartz glass with ferric nitrate, ethylenediamine (EDA), and triethanolamine (TEA) slurry, respectively. Results indicate that TEA slurry can provide excellent self-conditioning of FAP in fixed abrasive polishing of quartz glass. MRR and wear ratio maintain high levels during the whole polishing process. Friction coefficient and acoustic emission signal are more stable than that of the other two chemical additives. An appropriate amount of TEA, which is beneficial to enhance MRR and extends service life of FAP, is added in the polishing slurry to improve FAP self-conditioning in fixed abrasive polishing process.     

游离磨粒精密光整加工方法综述

指出了磨粒精密光整加工是先进制造技术的重要组成部分之一,是保证产品精度和表面质量的重要方法.磨粒光整加工在改善表面精度和提高表面层力学机械性能的同时,又提高了加工精度和表面完整性.论述了磨粒精密光整加工技术的原理、特点、关键技术及在工业生产中的具体应用,其目的是在装备制造业中,利用磨粒进行光整加工实现低成本、高表面完整性、高效率精密加工.     

电镀金刚石砂轮高效精密修整及熔融石英磨削试验研究

大尺寸光学玻璃元件主要采用细磨粒金刚石砂轮进行精密/超精密磨削加工,但存在砂轮修整频繁、工件表面面形精度难以保证、加工效率低等缺点。采用大磨粒金刚石砂轮进行加工则具有磨削比大、工件面形精度高等优点,然而高效精密的修整是其实现精密磨削的关键技术。采用Cr12钢对电镀金刚石砂轮(磨粒粒径151 μm)进行粗修整,借助修整区域聚集的热量加快金刚石的磨损,可使砂轮的回转误差快速降至10 μm以内。结合在线电解修锐技术,采用杯形金刚石修整滚轮对粗修整后的电镀砂轮进行精修整,砂轮的回转误差可达6 μm以内,轴向梯度误差由6 μm降至2.5 μm。通过对修整前后的金刚石砂轮表面磨损形貌成像及其拉曼光谱曲线分析了修整的机理。对应于不同的砂轮修整阶段进行熔融石英光学玻璃磨削试验,结果表明,砂轮回转误差较大时,工件材料表面以脆性断裂去除为主;随着砂轮回转误差和轴向梯度误差的减小,工件表面材料以塑性去除为主,磨削表面粗糙度为Ra19.6 nm,亚表层损伤深度低至2 μm。可见,经过精密修整的大磨粒电镀金刚石砂轮可以实现对光学玻璃的精密磨削。     

砂轮约束磨粒喷射加工外圆表面创成机理及三维形貌

磨粒喷射精密光整加工是重要零件在磨削后进行去除表面缺陷层、降低粗糙度和波纹度为目的光整加工新工艺。试验在MB1332A外圆磨床上完成,加工试样为表面粗糙度0.6 m左右的45钢。加工表面形貌和微观几何参数分别用扫描电子显微镜和Micromesvre2表面轮廓仪测量。应用自相关函数对磨削加工表面和光整加工表面进行分析,并研究材料去除机理和微观表面形貌的创成机理。在楔形区游离磨粒获得能量对工件进行抛磨、滑擦、和微切削是材料去除机理的核心因素,磨料流体侧向挤出是均化和降低表面波纹度的主要因素。试验结果表明,试样表面从连续的方向一致的沟槽被随机不连续的微坑所代替,表面粗糙度明显得到改善。随着加工循环的增加,工件表面的粗糙度值由0.6 m下降到0.2 m左右。此外,光整加工可以获得各向同性网纹交错的表面,表面轮廓的支撑长度率提高,对工件的耐磨性有利。     

开式砂带振动磨削

实验表明,在适当的加工条件下,砂带振动磨削不仅可降低工件的表面粗糙度,而且可以提高工件的形状精度。对一些砂轮磨削难以加工的工件,在普通床上安装磨削头架后就可以对其进行精加工。     

研磨压力对固结聚集体磨料垫自修正影响

固结磨料研磨过程中磨料的微破碎是实现固结磨料垫自修正特性的主要途径,研磨压力是影响磨粒微破碎的关键参数。选用单晶金刚石和聚集体金刚石作为磨粒制备固结磨料垫,在15 kPa压力下以石英玻璃为加工对象进行研磨实验,比较两者的材料去除率及加工稳定性;制备了4种陶瓷结合剂含量的聚集体金刚石,并制备成固结聚集体金刚石磨料垫,探索了不同压力下的固结聚集体金刚石磨料垫的自修正性能;分析了研磨后的工件表面粗糙度和表面微观形貌。结果表明:采用固结聚集体金刚石磨料垫,研磨后工件表面粗糙度低,去除效率稳定;在15~21 kPa的压力下,结合剂含量次高的聚集体金刚石研磨效率高,材料去除率达到8.94~12.43μm/min,加工性能较稳定,研磨后的工件表面粗糙度R a在60 nm左右;在3.5~7 kPa压力下,结合剂含量次低的聚集体金刚石研磨性能较稳定,材料去除率在2.67~3.12μm/min,研磨后的表面粗糙度R a在40 nm左右。高结合剂含量的聚集体金刚石磨粒更适合高研磨压力条件,而低结合剂的聚集体金刚石磨粒更适合于低研磨压力。     

电化学磁粒光整加工实验

从电化学磁粒光整加工对材料去除量和表面粗糙度影响规律的实验结果表明,由于磁粒加工过程中不断地去除钝化膜,使表面露出的新基体,从而进一步加速了电化学过程,实现表面整平,磁粒光整加工和电化学过程的复合,使光整加工效率和表面质量得到提高。     

多线砂轮复合自动修磨装置的设计与精度检验

多线砂轮复合自动修磨装置采用CNC数控系统,利用两个独立金刚石滚轮休整器,实现单支和多支砂轮的高精度修磨,极大地降低了人工操作带来的加工误差,提高了产品加工精度和效率。通过表面粗糙度检测数据可知,具有多线砂轮复合自动修磨装置的数控丝锥螺纹磨床完全符合加工精度要求。同时,采用多元回归方程建立基于砂轮修整参数的表面粗糙度预测模型,并设计单因素试验,得到砂轮修整参数与表面粗糙度之间的关系。由显著性分析结果得出,径向修整进给量是影响表面粗糙度的主要因素。     

MACHINING OF SODA LIME GLASS USING ABRASIVE HOT AIR JET: AN EXPERIMENTAL STUDY

Abrasive Jet Machining is becoming one of the most prominent machining techniques for glass and other brittle materials. In this article, an attempt has been made to combine abrasive and hot air to form an abrasive hot air jet. Abrasive hot air jet machining can be applied to various operations such as drilling, surface etching, grooving and micro finishing on the glass and its composites. The effect of air temperature on the material removal rate applied to the process of glass etching and grooving is discussed in this article. The roughness of machined surface is also analyzed. It is found that the Material Removal Rate (MRR) increases as the temperature of carrier media (air) is increased. The results have revealed that the roughness of machined surface is reduced by increasing temperature of carrier media. The mechanism of material removal rate has been discussed with aid of SEM micrographs.     

基于不同磨料的氮化硅陶瓷球精研工艺研究

为探究磨料对氮化硅陶瓷球精研加工的影响,从而提高氮化硅陶瓷球的表面质量和材料去除率,以基液种类、磨料种类和研磨盘转速为主要影响因素设计正交试验,并分析各因素对表面粗糙度Ra的影响程度。以表面粗糙度Ra和材料去除率为评价指标,通过单因素试验优化研磨参数。根据正交试验结果,得到精研加工过程中各影响因素对于表面粗糙度Ra的影响程度,从大到小排列依次为:磨料种类>基液种类>研磨盘转速。综合考虑陶瓷球精研加工的要求,确定最佳的研磨参数组合为:煤油基液、碳化硅磨料以及150 r/min的研磨盘转速。在金刚石、碳化硅、氮化硼、氧化铬和氧化铁这5种磨料中,氧化铁磨料修复粗研过后的氮化硅陶瓷球表面缺陷的效果最好。     

超声磁力复合研磨钛合金锥孔的试验研究

为了提高钛合金锥孔的研磨质量和研磨效率,提出了采用超声波振动辅助磁力研磨的复合加工方案。加工时,磨粒在磁场束缚下切削锥孔表面,并对其进行不断撞击,且因为磁场力、超声振动力和离心力等综合影响的原因,磨粒的切削轨迹呈现明显的多向性。针对钛合金锥孔,与传统磁力研磨法进行试验对比,并分析研磨后试件的材料去除量、表面粗糙度和表面形貌等来验证超声磁力复合研磨的效果。结果表明：超声磁力复合研磨加工效率得到提高;锥孔的材料去除量增加至1.6倍;研磨后锥孔平均表面粗糙度由原始的R_a1.23 μm降至R_a0.25 μm,下降率是传统工艺的1.3倍;试件表面的微波峰、凹坑和加工纹理均被去除,锥孔表面质量得到显著提高,且试件形状精度得到改善。