游离和固结金刚石磨料抛光手机面板玻璃的试验研究

选取不同粒径的金刚石微粉,采用游离磨料和固结磨料两种抛光方法加工手机面板玻璃,比较其材料去除率和抛光后工件表面粗糙度。结果表明：在相同的抛光工艺参数下,磨粒粒径在游离磨料抛光中对材料去除率和抛光后表面质量作用显著,而在固结磨料抛光中作用不显著;采用金刚石固结磨料抛光垫抛光能获得表面粗糙度约为Ra1.5 nm的良好表面质量,并在抛光过程中较好地实现了自修整功能。     

基于BP神经网络与遗传算法的固结磨具制作工艺参数优化

目的 利用BP神经网络技术与遗传算法寻找固结磨具制作最优工艺参数组合,实现固结磨具制作工艺参数的快速寻优.方法 设计磨粒粒径、磨粒质量分数、成型压力、烧结温度的正交工艺参数表,按正交表工艺参数制作蓝宝石晶片加工用的Cr2O3固结磨具,并且设计不同固化温度下制作的固结磨具的硬度与抗压强度测试试验,验证自制的固结磨具加工的...     

铝合金型材聚氨酯柔性垫弯曲研究

型材聚氨酯垫弯曲是一种将超弹性的聚氨酯垫作为弯曲凹模的型材弯曲新技术。通过调节型材压入聚氨酯垫的深度,可得到具有不同曲率半径甚至变曲率半径分布的零件。文章首先设计并制造了聚氨酯垫柔性弯曲装置。利用研制的聚氨酯垫柔性弯曲装置,以槽形截面铝合金型材为对象,通过实验,研究了压入深度和型材曲率半径的关系,以及型材截面形状对曲率半径的影响。结果表明,对于所研究型材,其曲率半径随压入深度的增加而减小。当压入深度较小时,曲率半径迅速减小;随着压入深度的继续增加,曲率半径的缓慢减小。当采用不同弯曲方式时,型材截面抗弯模量的变化以及截面中性层位置的变化,都对弯曲件的曲率半径有重要影响。截面抗弯模量越大弯曲越困难,截面中性层与压辊轴线的距离越大,曲率半径越小。     

Development of fixed-abrasive tool with spiral groove for decreasing the loading

The authors propose a fixed-abrasive tool with spiral groove on its surface, to eliminate or decrease the loading of swarf. The spiral groove, which is produced by a spiral wire wound around the tool, allows continuous evacuation of swarf and elongates the tool life. Through grinding experiments, it was confirmed that our spiral groove tool makes almost no loading of swarf while conventional fixed-abrasive tools easily make it. It was also shown that the spiral groove tool realizes a mirror finish even with ultra fine abrasive grains.     

Waviness removal in grinding of wire-sawn silicon wafers: 3D finite element analysis with designed experiments

Silicon wafers are used to fabricate more than 90% of integrated circuits. Surface grinding has been used to flatten wire-sawn silicon wafers. A major issue in grinding of wire-sawn wafers is that conventional grinding cannot effectively remove the waviness induced by wire-sawing process. Soft-pad grinding is a promising method to effectively remove waviness. This paper presents the results of three-dimensional (3D) finite element analysis of soft-pad grinding of wire-sawn silicon wafers. In this investigation, a four-factor two-level full factorial design is employed to reveal main effects as well as interaction effects of four factors (Young’s modulus, Poisson’s ratio, and thickness of the soft pad, and waviness wavelength of the wafer) on the effectiveness of waviness reduction. Implications of this study to manufacturing are also discussed.     

修整技术及提高固结磨料研磨垫自修整性的研究

随着化学机械研磨的持续进行,垫表面特征会发生变化,从而使其研磨能力大大降低。修整垫可改善表面轮廓,进而提高被加工晶片表面质量,而且可以减少表面缺陷,延长使用寿命。本文着重介绍固结磨料研磨垫常见修整技术,分为非自修整和自修整两种类型,非自修整法有高压水射流修整、超声波振动法修整、金刚石修整器修整。并重点阐述通过合理选用研磨液、添加成孔剂以及优化研抛工艺参数等措施来促进亲水性固结磨料研磨垫自修整。      

Fixed-abrasive grinding of brittle hard-disk substrates

An industry shift from aluminum-based hard-disk substrates to ceramic or glass substrates presents new challenges in high-precision machining. In this paper alternative brittle substrate materials are described. A fixed-abrasive grinding process is implemented using a specially configured precision grinding apparatus, and this process is proposed as an alternative to lapping and polishing for brittle substrates. Ductile-regime grinding techniques are used to machine ceramic substrates in one brittle material—glassy carbon—to optical quality on a two-axis, twin air-spindle grinding machine with nanometer-scale in-feed control. The machine's design and performance is described, as are a series of grinding experiments to fabricate glassy carbon hard-disks. Process innovations have resulted in a machine capable of finishing 0.9 mm-thick ceramic hard-disk substrates to 8 nm rms roughness and 8 μm flatness without lapping or polishing.     

应用弹性砂轮对铝合金镜面磨削工艺研究

目的解决铝合金手机外壳传统抛光工艺中存在的抛光效率低等问题。方法采用聚氨酯弹性砂轮对6061铝合金进行了磨削加工,使用正交试验研究了磨料粒度、进给速度、切削深度、砂轮线速度对加工表面粗糙度及材料去除率的影响。试验中使用折线走刀方式进行加工,可减轻磨料分布不均带来的影响。使用白光干涉仪测量了加工后表面的粗糙度,通过计算单位时间内工件的质量变化得出了去除率,并通过对结果的综合优化得出了最优工艺参数。结果在选取的16组磨削工艺参数中,可获得的最低表面粗糙度为44.87 nm,最大去除率为0.329 g/min。对表面粗糙度影响最大的因素为磨料粒度,影响最小的因素为进给速度;对材料去除率影响最大的因素为切削深度,影响最小的为进给速度。经过综合优化,最佳工艺参数组合为:砂轮600#,转速2000 r/min,切削深度0.04 mm,进给速度20 mm/min。结论弹性聚氨酯砂轮应用于铝合金磨削可提高加工表面质量,可简化工艺流程,节省备料和安装调整时间,从而提高效率。     

Fabrication and abrasive wear properties of metal matrix composites reinforced with three-dimensional network structure

1. Introduction Metal matrix composites (MMCs) have some re- inforcements such as particle, whisker, and fiber [1-3] as well as the three-dimensional network structure [4]. In recent years, metal matrix compos- ites reinforced with three-dimensional network structure (3DNRMMCs) have been paid consider- able attention, since they possess a rather high spe- cific strength, stiffness, and wear-resistance and can be attractive candidates for structural and functional materials [5]. There are s…     

固结磨料研磨与抛光的研究现状与展望

分析了传统游离磨料研磨抛光存在的缺点和固结磨料的研磨抛光的优点;阐述了固结磨料研磨抛光的材料去除机制以及固结磨料研磨盘抛光技术在氮化硅陶瓷加工、半导体制程中的应用;介绍了多种固结磨料研磨盘、抛光垫的制作方法;并展望了固结磨料的研磨抛光的发展趋势。     

Force control grinding of gamma titanium aluminide

This paper addresses the grinding of ordered intermetallic compounds and their brittleness at ambient temperature. The depth of plastic deformation is supposed as the measure of surface integrity. The current paper expands the work of a previously reported indentation model that correlated the depth of plastic deformation and the normal component of the grinding force. This paper studies the indentation model using force control grinding of gamma titanium aluminide (TiAl-γ). Reciprocating surface grinding is carried out for a range of normal force 15–90 N, a cutting depth of 20–40 μm and removal rate of 1–9 mm³/sec using diamond, cubic boron nitride (CBN) and aluminum oxide (Al₂O₃) abrasives. The measured depths of plastic deformation are in the range of 150–300 μm. The deviations from the indentation model are explained by changes in the ductility during the grinding process. Furthermore, a force-based model for specific energy is developed and evaluated. The measured specific energies are in the range of 40 J/mm³ (diamond) to 400 J/mm³ (CBN).     

Spiral-structured fixed-abrasive pads for glass finishing

Loose-abrasive machining with cerium oxide (ceria) slurry is traditionally employed for finishing glass. However, the use of slurries can have a detrimental impact on the environment. Fixed-abrasive machining has received attention as an alternative technology; however, conventional fixed-abrasive tools are inefficient. In this study, spiral-structured pads with fixed-abrasive layers and abrasive holding layers are introduced to increase the quality and efficiency of fixed-abrasive tools. The finishing experiments revealed a much higher finishing efficiency and good surface quality compared to those obtained in conventional polishing with ceria slurry.     

High Wear-Resistant Aluminum Matrix Composite Layer Fabricated by MIG Welding with Lateral B<Subscript>4</Subscript>C Powder Injection

In this work, a low-cost technique combining MIG welding and lateral powder injection was developed to fabricate B₄C particles-reinforced aluminum matrix composite (AMC) layer on a T6 heat-treated 7075 aluminum alloy (AA7075-T6) substrate. The AMC layer was 6-7 mm thick and well bonded to the substrate. The B₄C particles were dispersed throughout the AMC layer with an average content of approximately 7 vol.%. No significant reaction products existed either at the particle–matrix interface or in the Al-matrix. In pin-on-disk dry sliding wear tests against Al₂O₃ grinding wheels, the AMC layer exhibited excellent wear resistance with volume wear rate approximately 1/10-3/10 that of the quenched AISI 1045 steel and only approximately 2-7% that of the AA7075-T6 alloy under the same wear conditions. A small addition of ceramic particles can greatly improve wear resistance, suggesting that this technique has good prospects for a wide variety of applications.     

薄片零件的冲裁

用常规钢制冲模冲裁薄片零件,断口常有毛刺。聚氨酯冲裁模能自动调整间隙,同一副模具可冲制不同厚度的薄片零件,制件平整光洁、无毛刺,模具结构简单、制造容易,适宜薄料的冲裁。     

立方氮化硼砂轮的研究与发展

介绍了国内外立方氮化硼（CBN）砂轮的性能和金属结合剂（含电镀和钎焊结合剂）、树脂结合剂和陶瓷结合剂CBN砂轮的特点,论述了CBN砂轮中磨料的处理及气孔组织的调控技术。阐述了目前国内在CBN砂轮制造水平方面与国外存在的差距,提出CBN砂轮的未来制造应向着超高速、绿色制造等方向发展。      

Effect of tool rotating rate on foaming properties of porous aluminum fabricated by using friction stir processing

A1050 porous aluminum is fabricated by the FSP route and the effect of the tool rotating rate on the porosity and morphology of the pores is investigated. To fabricate high-porosity porous aluminum with a uniform pore size distribution, a certain amount of stirring action is necessary; however, excessive stirring action is ineffective. A sufficiently uniform mixture is realized by traversing the FSP tool two times at a tool rotating rate exceeding 2200 rpm. The results indicate the minimum necessary amount of stirring action and will provide a guideline for improving productivity. Also, to improve the morphology of pores, optimizing the amount of Al₂O₃ is effective. Closed-cell porous aluminum with a porosity of about 80% was successfully fabricated by 2-pass FSP at 2200 rpm with the addition of 7 mass% Al₂O₃, a holding temperature of 998 K and a holding time of 10 min.     

Development of discontinuous grinding wheel with multi-porous grooves

Conventionally, grinding of aluminium, copper and stainless steel is difficult owing to the mechanical properties such as low hardness and high toughness which result in the wheel loading and poor surface finish. In order to grind these materials easily, a discontinuous grinding wheel with multi-porous grooves has been recently developed. The multi-porous grooves were formed during wheel manufacturing. The discontinuous grinding wheel dramatically increases the grinding performance. It is desirable to use discontinuous grinding wheel when grinding materials with high efficiency and accuracy which is impossible using conventional wheels.In this paper, the construction and manufacturing method of discontinuous grinding wheel with multi-porous grooves are explained. The grinding characteristics of the discontinuous grinding wheel is also illustrated.     

Modeling of contact behavior between polishing pad and workpiece surface

The polishing pad is one of the most significant components within a polishing system. It influences both the material removal rate and the surface finish. Furthermore, the wear behavior of the polishing pad is responsible for the shape accuracy. Nevertheless despite extensive research activity in recent years, there are still gaps of knowledge in terms of the working principle of a polishing pad. In this paper, the contact behavior of a polishing pad (polyurethane foam) with the workpiece surface is examined. For this, the polishing pad is modeled using a finite-element modeling (FEM) program and the deformation by pressing it against the rigid workpiece surface is investigated. Consequently, the local tensions are calculated, which are the basis for the penetration depth and therefore also for the material removal rate. The investigations presented in this paper were carried out within the research project SFB TR/4 funded by the German Research Association, Deutsche Forschungsgemeinschaft (DFG).     

Hot profile extrusion of AA-6060 aluminum chips

Analyses of energy consumption in manufacturing processes have shown that most of the energy is needed for the production of material such as aluminum or steel and not for further manufacturing steps like forming or cutting. To reduce energy consumption and also a reduction of CO₂ emissions in manufacturing processes, a reduction of the amount of primary material, made from first melting after mining, as well as secondary material, made from melting of recycled scrap material, is needed. In this work, the re-use of aluminum AA-6060 scrap based on milling and turning chips, by direct hot extrusion is presented. To prevent further use of primary aluminum or melting of the chips the process aims at using compacted chips as billet material. The production of the chips as well as the compaction of billets, the extrusion process and the properties of the final profile is presented. In addition to the use of chips based on one alloy the mixture and extrusion of aluminum and SiC particles is presented. The investigations have shown that using billets made of AA-6060 chips can lead to similar mechanical and microstructural properties as using of conventional cast aluminum billets. Investigations on an additional cutting or drilling of the extruded profiles have shown even improved properties due to a reduced chip length.     

Ultra-thinning Processing of Dielectric Substrates by Precision Abrasive Machining

The ultra-thin dielectric substrate was obtained by precision grinding and lapping/polishing. In the precision grinding, the substrate was thinned until 50 μm in thickness using fine-grained diamond wheels and a polishing pad. The substrates in the lapping and polishing were thinned to 17 μm in thickness with good flatness. The good flatness was produced by hard polishing pad made of polyvinyl chloride resin owing to their mechanical properties of high fixed grain density. These were confirmed by detailed AFM observations. Finally, the substrates were segmentalized to produce five thousand small tips (2 mm × 0.4 mm) by a precision dicing device.