液体辅助激光加工硬脆材料及其应用

硬脆材料由于具有稳定的机械和化学性能、优良的光电特性等优势，在航空航天、光电工业等领域具有广泛的应用。激光加工由于具有高精度、高能量、非接触式加工等特点，是实现硬脆材料加工的理想技术。为了实现硬脆材料的去除加工，通常需要较高的激光能量，使得加工的结构精度较低，而且表面质量较差。本综述介绍了液体辅助激光加工技术在硬脆材料加工方面的研究进展，分别介绍了液相激光烧蚀、激光诱导背部湿法刻蚀和刻蚀辅助激光改性等三种液体辅助激光加工技术的原理，对比了各自的优势和不足，以及不同加工技术、辅助液体种类以及加工参数等对不同硬脆材料加工质量的影响，介绍了液体辅助激光加工技术目前主要的应用，最后，简要阐述了该技术存在的问题和未来的潜在发展。     

微磨削与超声振动复合加工技术研究现状与展望

微细切削技术是传统加工工艺向微观尺度的延伸,在微加工领域具有重要的作用,尤其适用于三维零件及微结构的加工。与其他微细切削技术相比,微细磨削技术具有加工零件棱边精度高、适于硬脆性材料加工等优势,但其存在加工效率低、磨削热量大、微砂轮易磨损等缺陷。已有研究表明,于机械加工辅加超声振动的复合加工技术可有效降低切削力、切削温度,增大脆性材料脆-塑转变临界切削深度,改善加工表面质量等。因而超声振动辅助微磨削技术被认为是一种可有效解决微磨削加工现存缺陷的技术。主要从微磨削技术研究现状、尺寸效应机理研究、脆性材料塑性域去除机理研究、超声振动切削实验研究、超声振动切削断续切削机理研究及微磨削动态有效磨刃密度建模研究六个方面,对微磨削技术及超声振动辅助切削技术相关领域研究进行综述,并探讨超声振动辅助微细磨削技术加工机理研究及未来发展需注重解决的问题。     

硬脆材料加工中超硬刀具的应用

在硬脆材料的加工中,对刀具材料的要求越来越高,硬度高、性能好的刀具已成为加工过程中理想的刀具。近年研制成功的超硬刀具,由于的性能好,耐用度高、综合成本低等特点,应用越来越广泛。本文主要针对超硬刀具在硬脆材料中的应用进行分析,使超硬刀具在今后能够得到更好的发展以及更加广泛的应用。     

高效加工技术及其应用研究

在机械加工领域,切削加工是应用最广泛的一种加工方法,其发展方向主要是研究高速切削,对超硬材料加工,主要是发展磨削、超声和放电等高效复合加工技术。章介绍对高效切削加工和高效复合加工技术的理论研究和技术开发与应用及所取得的重要成果,主要包括高速切削基础理论、陶瓷刀具材料研究新体系和超硬材料断续磨、超声和电火花的复合加工理论与技术的研究开发。生产实际应用结果表明,高效加工技术可以大幅度提高加工效率,改善加工表面质量,降低加工成本。     

超声振动辅助单晶硅划片的锯切力研究

采用金刚石超薄锯片对单晶硅划片的工艺会在划片时产生较大锯切力,从而导致较大的崩边损伤。而旋转超声辅助加工由于超声振动的作用可以减小加工时所产的切削力,同时获得较好的加工精度,越来越广泛地应用于硬脆材料的加工中。为了验证超声辅助对单晶硅划片中锯切力的作用,在实验中将超声振动添加到锯片上,使其产生径向的振动来完成对单晶硅的划片。并通过对比有超声振动辅助与无超声振动辅助的单晶硅划片的锯切力,对超声振动辅助划片中锯切力的特点进行分析。实验结果表明,超声辅助划片所产生的锯切力比无超声辅助划片所产生的锯切力小,说明超声振动的添加可以降低锯切力。同时在超声划片中产生的崩边要小于非超声加工条件下的崩边情况,说明超声振动降低锯切力可抑制硅片的崩边。     

超声振动辅助磁粒研磨技术的研究进展

超声振动辅助磁粒研磨技术是在磁粒研磨的基础上增加了超声波振动功能，可以在短时间内将表面抛光至纳米级别，因其具有辅助研磨效果佳、可控性和适用性好等优点，在越来越多的领域得到了应用。首先对超声辅助磁粒研磨加工技术的发展概况进行了简要介绍，分别从表面粗糙度、材料去除率、显微组织和残余应力等方面进行了重点分析和总结。其次，超声振动工艺参数是影响研磨效果的重要因素，优化选取振幅、振动频率、主轴转速以及磨料粒径等工艺参数可以明显提高研磨效果。此外还要考虑合适的加工时间和加工间隙，从而对复杂曲面进行精密研磨。最后，提出了超声振动辅助磁粒研磨加工技术研究中存在的一些缺陷，并对其未来的发展趋势进行了展望。     

超声振动辅助塑性成形及形性预测研究进展

随着微机电系统等领域的快速发展,对零件成形精度与性能的要求日益增加。超声振动辅助塑性成形是一种典型的能场辅助塑性成形工艺,相比于传统塑性成形工艺,具有流动应力低、材料成形能力高、界面摩擦少、成形质量较好等优势,被广泛应用于难成形材料加工、微成形、复杂构件成形等塑性成形过程。然而,由于不同塑性成形工艺中金属的变形行为特性存在较大差异,对塑性成形质量与成形性能进行预测有利于实现成形过程的形性协同控制。介绍了超声振动辅助塑性成形在体积成形工艺（镦粗、挤压、拉拔等）与板料成形工艺（拉伸、拉深、渐进成形、冲压等）中的应用及发展概况,讨论了超声振动对材料塑性变形过程中宏观表现与微观演化的影响。在已有研究基础上,重点分析了超声振动辅助塑性成形过程中成形能力预测（流动应力、成形极限等方面）和成形性能预测（表面性能、力学性能、微观组织等方面）的研究进展,为金属零部件成形高质量形性调控提供理论参考,并展望了超声辅助塑性成形工艺的发展趋势。     

超声辅助冷冻技术在食品浸渍式冷冻中的研究进展

目的 概述超声辅助冷冻技术在食品浸渍式冷冻中的研究进展,为今后新型技术辅助浸渍式冷冻提供研究方向.方法 研究超声辅助冷冻的成核机理和对冰晶生长的影响,以及超声对溶液性质的影响,并对超声辅助冷冻技术在食品浸渍式冷冻中的应用进行综述.结论 超声辅助浸渍式冷冻技术可以广泛应用在各类食品加工中,有很大的研究和发展空间.超声辅助冷冻技术能够进一步加快食品浸渍式冷冻的冻结速率,减小食品内部冰晶尺寸,较好地改善了冷冻食品的品质和风味,在食品加工中具有广阔的应用前景,可以高效应用于食品工业.     

精密测量和加工中的激光技术

激光具有高方向性、高单色性、高相干性以及普通光源达不到的能量密度等优点。近年来,由于激光技术具有高准确度、非接触、稳定性好等独特优点,在精密加工和测量领域受到了广泛关注。本文综述了激光技术在精密测量和加工领域的应用现状,并根据其测量原理和应用场景的不同进行分类和总结。在现有发展现状的基础上,对激光技术在精密测量和加工领域的发展趋势进行了分析和展望,为进一步推动激光技术在精密测量和精密加工领域的应用提供参考。     

直写成型无机非金属材料及其结构/功能应用进展

无机非金属材料因突出的力学、电学、磁学、声学、光学及热学性能而备受关注，但受制于其固有的低延展性和硬脆特性而加工困难。直写成型技术作为一种被广泛采用的3D打印技术，可利用粉体、前驱体等原料配制流变性能适宜的浆料实现复杂结构无机非金属材料零部件的成型，具有原料选材广泛、设备廉价、工艺简单等优势，能够有效提高所需产品设计—制造—测试—应用整个周期的效率，已被广泛应用于航空航天、医药、能源、建筑等领域的科研探索。基于直写成型技术在无机非金属材料零部件制备及结构/功能化应用方面的进展，概述了无机非金属材料3D打印技术的发展及直写成型的技术特征；分类介绍了直写成型在储能器件、建筑材料、组织工程、先进陶瓷等领域的应用特点及进展，并对其在相应领域的发展和挑战进行适当评述。     

Rotary Ultrasonic Machining: A Review

Rotary ultrasonic machining (RUM) is a mechanical type of nontraditional hybrid machining process that has been utilized potentially to machine a wide range of latest and difficult-to-machine materials, including ductile, hard and brittle, ceramics, composites, etc. In RUM, the basic material removal phenomenon of ultrasonic machining (USM) and conventional diamond grinding amalgamates together and results in higher material removal rate (MRR), improved hole accuracy with superior surface finish. In the current article, several investigations carried out in the domain of RUM for enormous materials have been critically reviewed and reported. It also highlights several experimental and theoretical ensues of RUM to improve the process outcomes and it is reported that process performance can be substantially improved by making the right selection of machine, diamond tooling, material and operating parameters. In recent years, various investigators have explored umpteen ways to enhance the RUM process performance by probing the different factors that influence the quality attributes. Among the various accessible modifications in RUM as employed in industries, rotary ultrasonic drilling is more strongly established compared to other versions such as rotary ultrasonic side milling, face milling, grinding, surface texturing, etc. The micro machining applications of RUM have also been discussed briefly. The final section of this paper discusses RUM developments and outlines the aspects for future research.     

Machining MMC engineering components with polycrystalline diamond and diamond grinding

Abstract

The high specific strength of metal matrix composite (MMC) materials is derived from the combined effects of light, ductile and hard, brittle materials being incorporated in a matrix composite. The hard, brittle phase in this composite can cause problems when machining such materials. The most commonly encountered problems are those involved in producing an acceptable surface finish, avoiding very rapid tool wear and achieving acceptable machining costs, through the use of higher machining speeds. However, in order for MMC materials to be widely accepted into the mainstream automotive, aerospace, and mechanical engineering industries, cost effective machining solutions will be required. Increasingly, machining with polycrystalline diamond (PCD) and grinding with diamond abrasives (two examples of ultra hard materials) are being utilised as the most effective machining methods in the manufacture of MMC components. The present paper explores the inherent problems involved in the machining of MMCs and the suitability of ultrahard tooling technology in overcoming many of these problems. The importance of PCD grade selection and optimised machining conditions are particularly important when machining MMCs, and these are reviewed in detail. The versatility of PCD for use in practically all metal cutting operations is also illustrated. The paper concludes with a number of case studies demonstrating how ultrahard tooling technology has been applied to produce economically a wide range of engineered MMC components in the automotive, aerospace, and mechanical engineering industries.     

Material selection for the tool holder working under hard milling conditions using different multi criteria decision making methods

Nowadays machining of materials in their hardened state, also called hard machining, is a challenge in production of tools and molds. It has some advantages such as lower process time and lower manufacturing cost when compared to conventional machining. In machining of hard workpiece materials, however, very high stresses act on the tool holder through the cutting tool. These stresses necessitate the tool holder to have some specific properties. Especially in hard milling, the tool holder should have high stiffness and should be able to dissipate the energy generated during interrupted cutting. Material cost of the tool holder is also important since lower costs provide a competitive advantage for manufacturers. The material selection for the tool holder should be conducted considering aforementioned requirements. To tackle the difficulty of the material selection with specific properties from a large number of alternatives, multi-criteria decision-making (MCDM) methods have been used. In this paper a decision model including extended PROMETHEE II (EXPROM2) (preference ranking organization method for enrichment evaluation), TOPSIS (technique for order performance by similarity to ideal solution) and VIKOR (VIšekriterijumsko KOmpromisno Rangiranje) methods were used for the selection of the best material for the tool holder used in hard milling. The criteria weighting was performed by compromised weighting method composed of AHP (analytic hierarchy process) and Entropy methods. The candidate materials were ranked by using these methods and the results obtained by each method were compared. It was confirmed that MCDM methods can be used for the solution of real time material selection problems. Tungsten carbide–cobalt and Fe–5Cr–Mo–V aircraft steel were found as the best materials for the tool holder production. The obtained results are found to be rather satisfactory and can be used in design stage of hard machining operations.     

Experimental Investigation on Rotary Ultrasonic Face Grinding of SiCp/Al Composites

SiCp/Al composites have been widely used in many fields such as aerospace, automobile, advanced weapon system, etc. But this kind of material, especially with high volume fraction, is difficult to machine due to the reinforced particles existing in matrix, which has limited its further application. Rotary ultrasonic machining (RUM) has many excellent features and it has never been used to machine SiCp/Al composites. In order to improve the machinability and application of SiCp/Al composites, the rotary ultrasonic face grinding experiments of SiCp/Al composites reinforced with 45% volume SiC particles were carried out to investigate cutting force, surface quality, tool wear, and abrasive chip shapes. The experimental results indicate that ultrasonic vibration could reduce cutting force, surface roughness, surface defects, and increase plastic removal ratio. The cutting force could be lowered by an average of 13.86% and the surface roughness could be lowered by an average of 11.53%. The examined results of tool wear patterns suggest that tool wear is mainly caused by grain breakage and grain fall-off. Grinding wheel blockage and grinding burn were not observed in machining process.     

Correlation between edge radius of the cBN cutting tool and surface quality in hard turning

cBN cutting tools with superior mechanical properties are widely used in machining various hard materials. The microgeometry of cBN cutting tools, such as the edge radius, has great influence on the surface quality of components and tool life. For optimized tool geometry, it is crucial to understand the influence of the cBN cutting tool microgeometry on the machined surface quality. In this study, the attempt has been made to investigate the correlation between the cutting tool edge radius and surface quality in terms of the surface roughness and subsurface deformation through a FE simulation and experiment. Machining tests under different machining conditions were also conducted and the surface roughness and subsurface deformation were measured. Surface roughness and subsurface deformation were produced by the cutting tools with different edge radii under various cutting parameters. Both results from the FE simulation and machining tests confirmed that there was a significant influence on the surface quality in terms of both the surface roughness and subsurface quality from the edge radius. There is a critical edge radius ofcBN tools in hard turning in terms of surface quality generated.     

Machining of high performance workpiece materials with CBN coated cutting tools

The machining of high performance workpiece materials requires significantly harder cutting materials. In hard machining, the early tool wear occurs due to high process forces and temperatures. The hardest known material is the diamond, but steel materials cannot be machined with diamond tools because of the reactivity of iron with carbon. Cubic boron nitride (cBN) is the second hardest of all known materials. The supply of such PcBN indexable inserts, which are only geometrically simple and available, requires several work procedures and is cost-intensive. The development of a cBN coating for cutting tools, combine the advantages of a thin film system and of cBN. Flexible cemented carbide tools, in respect to the geometry can be coated. The cBN films with a thickness of up to 2 µm on cemented carbide substrates show excellent mechanical and physical properties. This paper describes the results of the machining of various workpiece materials in turning and milling operations regarding the tool life, resultant cutting force components and workpiece surface roughness. In turning tests of Inconel 718 and milling tests of chrome steel the high potential of cBN coatings for dry machining was proven. The results of the experiments were compared with common used tool coatings for the hard machining. Additionally, the wear mechanisms adhesion, abrasion, surface fatigue and tribo-oxidation were researched in model wear experiments.     

Mechanische Bearbeitung sprödharter Körper und Grenzflächenwechselwirkungen

The effect of surface adsorption on the machining of brittle materials In the present paper is shown the importance of interfacial phenomena in the machining (grinding, cutting) of brittle materials. Especially influenced are the rate of the abrasion, the cutting forces and the roughness of the surface.     

Aktuelle Entwicklungen bei Schichtsystemen für die Trockenbearbeitung. Recent developments in coating systems for dry machining

In the recent years dry machining, i.e. machining without or with a minimal amount of coolants and lubricants has developed to an ecological and economical alternative to the conventional production methods, also under the impression of changes in the awareness. Temperature stability of the tool materials plays an important part at the implementation of this technology. With a number of recently developed hard material layers they try to increase high temperature stability of the cutting edges of tools under maintaining their hardness. The latest developments in the tools sector such as super nitrides and nanocomposite layers reveal considerable potentials especially for dry machining.