塑料加工最新技术——激光加工

简要介绍了塑料加工技术——激光加工技术的起源、发展过程及应用领域。详细介绍了塑料的激光焊接技术、激光打孔技术、激光标志技术和激光切割技术的应用技术、方法特点和发展趋势。     

激光清洗原理与应用研究

利用激光清除污物、清洗微粒是近年来激光加工技术应用的一个新领域。本文介绍激光清洗的基本原理，讨论激光清洗的应用及发展方向等问题。     

激光精密加工的发展趋势

激光加工装备用途广泛前景广阔，代表精密加工的发展方向，激光按照光源分类可分为固体激光、半导体激光、气体激光等；按照产业分，通常国际上把激光产业分为通信用激光器件、数字化激光存储器件、激光加工装备、激光标记包装装备、激光照排和印刷、激光医疗设备、激光测距准直检测仪器仪表、文娱教育激光仪器设备、激光用材料元器件和部件等10大类。     

修补模具的新选择——激光沉积焊接技术

激光沉积焊接技术以其优于传统模具修补工艺的加工质量和精确度已成为注塑加工商在修补模具时的新选择。特别是在欧洲和美国，该技术目前已得到了广泛使用。     

激光技术在材料加工领域的应用探究

激光的出现改变了人们的生产生活,当前激光技术已经被广泛地应用于各行各业,并发挥着巨大作用。尤其是在材料加工领域,激光技术有着其他加工技术所无法企及的优势,从而被誉为"21世纪的加工技术"。本文在概述激光技术的基础上,探讨了激光技术在材料加工领域的应用,并据此提出了相关展望。     

脉冲激光技术在高分子材料加工中的应用

随着我国科学技术水平的不断提高以及诸多科研人员的努力,激光技术获得了飞速的发展,超短脉冲、超高强度、超短波长等成为了当前激光技术的代表特征,脉冲激光技术的出现更为高分子材料加工带来了革命性的进步。在分析脉冲激光技术在高分子材料加工中的应用时,首先对脉冲激光及其折射率改性情况进行了概述,在此基础上从激光烧烛产生表面多孔结构、周期结构以及块体材料加工对材脉冲激光技术的应用几个方面进行了详细的研究与探讨。     

日本制成下一代激光加工系统核心装置

日本理化研究所和产业技术综合研究所目前发布消息说，两家机构联合研制出高效率的超短脉冲激光发生装置，向下一代激光加工系统的产业化应用迈出了重要一步。 两家机构联合发布的新闻公报说，随着激光技术的进展，人们已经实现了激光发生时间仅l飞秒（1飞秒等于一千万亿分之一秒）的超短脉冲激光，激光的输出功率已达上万亿瓦。     

激光技术在化学加工业中的应用

<正> 诞生于一九六一年的激光技术已被公认为本世纪最伟大的成就之一,广泛应用于医学、建筑工业、机械加工业、微电子工业,同时也因其突出的优良特性而应用于化学加工业中,实现一些特殊的反应和加工一些特殊的材料。四十年来激光技术在化学加工业中的应用成就主要归纳如下: 一、激光分离技术利用激光来分离某些物质如同位素、稀土元素,就是激光技术在化学加工业中应用的最杰出的成就之一。利用激光来分离同位     

激光清洗轮胎模具新工艺

激光清洗轮胎模具的原理是利用模具基体物质与表面附着的污垢对某一频率的激光能量吸收系数的差别，使激光能量充分被表面附着的污垢所吸收，从而受热膨胀直至气化，所形成的气体被吸收利用而不损伤甚至强化模具基体，以达到绿色清洗的目的。本文从激光的特性、激光器简介、激光清洗原理以及激光清洗应用分析等方面对激光加工技术新应用进行了探讨。     

国内外模具制造技术的新发展

激光因具有单色性、相干性和平行性三大特点,特别适用于材料加工.激光加工是激光应用最有发展前途的领域,国外已开发出20多种激光加工技术.激光的空间控制性和时间控制性很好,对加工对象的材质、形状、尺寸和加工环境的适应性很强,特别适用于自动化加工.     

基于冻结浆料的分层实体制造法加工陶瓷坯体

提出了一种新型陶瓷增材制造方法,浆料由陶瓷粉末、有机粘结剂和去离子水构成,单层生坯的加工过程包括:铺料、冷冻和激光扫描,层层累积成型后,将冻结状态坯体置于冷冻干燥机中干燥,得到陶瓷生坯;分析了激光加工参数和浆料固含量对于激光扫描过程的影响.结果表明:采用激光扫描图形轮廓的方式,避免了激光辐照对材料内部结构的破坏;通过与冷冻干燥技术的结合,充分保留了片层状的孔隙结构;随着激光能量密度的增大,激光扫描线的宽度和激光切割的深度增大;随着浆料固含量的增加,受陶瓷颗粒对激光能量产生散射作用的影响,激光的切割深度减小.     

Process development for the laser powder bed fusion of WC-Ni Cermets using sintered-agglomerated powder

Although ceramic particle-metal matrix materials (i.e., cermets) can offer superior performance, manufacturing these materials via conventional means is difficult compared to the manufacturing of metal alloys. This study leverages the laser powder bed fusion (LPBF) process to additively manufacture dense tungsten carbide (WC)-17 wt.% nickel (Ni) composite specimens using novel spherical, sintered-agglomerated composite powder. A range of processing parameters yielding high-density specimens was discovered using a sequential series of experiments comprised of single bead, multi-layer, and cylindrical builds. Cylinders with a relative density >99% were fabricated and characterized in terms of microstructure, chemical composition, and hardness. Scanning electron microscopy images show favorable wetting between the Ni binder and carbide particles without any phase segregation and laser processing increased the average carbide particle size. Energy dispersive X-ray and X-ray diffraction analyses detected traces of secondary products after laser processing. For samples processed at high energy densities, complex carbides and carbon agglomerate phases were detected. The maximum hardness of 60.38 Rockwell C is achieved in the printed samples. The successful builds in this study open the way for LPBF of dense WC-Ni parts with a large workable laser power-laser velocity processing window.     

选择性激光烧结用聚合物基材料制备研究进展

选择性激光烧结（selective laser sintering, SLS）是一种重要的3D打印加工技术,可制备传统加工无法制备的任意复杂形状的制件,广泛应用于航空航天、国防装备、医疗器械以及汽车等高新技术领域。本文介绍了SLS技术的加工原理和优势,综述了SLS技术加工成形用材料种类及聚合物基粉体材料的制备方法,主要包括相分离法、机械粉碎法、溶液法和喷雾干燥法。重点对SLS技术制备聚合物基压电复合材料及制品的国内外研究现状进行总结。虽然SLS打印制造技术面临聚合物原料种类少、功能缺乏、粉体生产成本高以及难以批量制备等瓶颈问题,但经过不断地创新与发展,SLS打印技术将成为高性能多功能高分子复合材料及其大型复杂制件的极佳制造方法。     

陶瓷增材制造(3D打印)技术研究进展

高性能陶瓷是现代技术发展和应用不可或缺的关键材料。常规的陶瓷制造技术难以满足对个性化、精细化、轻量化和复杂化的高端产品快速制造的需求。新兴的增材制造技术(3D打印)在高性能陶瓷的成型制造领域具有巨大的发展潜力,有望突破传统陶瓷加工和生产的技术瓶颈,为陶瓷关键零部件的应用开辟新的途径。本文针对陶瓷材料及其快速成型和后处理工艺,重点阐述了三维打印技术、光固化成型技术、选择性激光烧结技术等主流陶瓷增材制造技术的研究现状,并指出了目前存在的问题及发展趋势。     

大型往复压缩机曲轴裂纹的激光熔覆修复

阐述了激光熔覆技术的原理与特点,介绍了应用激光熔覆技术修复大型往复压缩机曲轴曲柄销表面裂纹的简要过程及该曲轴修复后的运行情况。实践证明,激光熔覆技术具有覆层缺陷率低、组织细密、性能优异、与基体结合牢固及在加工过程中对基体的热影响极小、工件变形小等优点。     

Femtosecond laser micro-milling dental glass ceramics: An experimental analysis and COMSOL finite element simulation

Dental glass ceramic materials are widely used in all-ceramic restoration technology. In order to effectively solve the problems existing in the process of traditional diamond cutter milling dental glass ceramic materials, such as severe needle loss, large tool wear and general milling efficiency, a new method of ultrafast laser milling dental glass ceramics is proposed. In this paper, 1030 nm femtosecond laser with pulse width of 600fs was used to micro-mill dental glass ceramics. Confocal laser microscopy was used to measure the milling depth and surface roughness of single-layer milling under selected laser processing parameters. The pre-layered milling software was developed to control the z-axis lifting and to compensate the focal length synchronously. Scanning electron microscope (SEM), Raman spectrometer and Vickers micro-hardness tester were used to characterize the dental glass ceramics after femtosecond laser milling. The results showed that under the specific laser processing parameters, the infrared femtosecond laser milling system can achieve a good processing morphology without changing the surface composition and surface hardness of dental glass ceramics. This new dental glass ceramics processing method based on ultrafast laser technique indicated a new direction for further chair processing of dental all-ceramic restoration technology.     

Micromachining porous alumina ceramic for high quality trimming of turbine blade cores via double femtosecond laser scanning

Turbine blade cores are made of porous alumina ceramic and determine the molding accuracy of the cavity of turbine blades, which strongly affect thermal diffusion performance and service life of turbine engines. To get a high quality ceramic core, accurate trimming for a preliminarily processed core is needed and therefore, micromachining porous alumina ceramic, which differs from general alumina substrates, is crucial. This paper dealt with a processing technology for the special material via double femtosecond laser scanning. The materials ablation threshold was firstly determined through parameter fitting and then this material was machined at a combination of different laser processing parameters. Considering the produced debris blocks the lasers further propagation into the material, double femtosecond laser scanning was newly proposed and experimentally verified with the comparison of gas jet assist and underwater laser processing ways. The removal profiles of the machined material were characterized in terms of cutting width, cutting depth, deviation of linearity and surface morphology, which exhibited high dependence on the femtosecond laser processing parameters. The optimal laser operating window was identified and high quality laser cutting of the porous alumina ceramic was demonstrated. The developed processing technology has potential application in trimming for ceramic casting cores. In addition, it might also give a novel view for high quality laser micromachining another materials.     

塑料激光焊接加工技术

传统的塑料焊接技术包括最新的激光焊接技术都只能对二维部件进行焊接,新的三维塑料激光焊接技术却能突破两维的障碍,它可以使三维的物体天衣无缝地拼接起来,不仅提高了产品的质量,也降低了生产成本。阐述激光焊接技术的基本原理及其特点,综述了激光加工设备的新的应用领域,激光焊接塑料的工艺和设备;以及激光焊接塑料的材料;同时指出了激光焊接塑料的应用发展方向。     

Direct laser additive manufacturing of high performance oxide ceramics: A state-of-the-art review

The implementation of additive manufacturing for ceramics is more challenging than for other material classes, since most of the shaping methods require polymer binder. Laser additive manufacturing (LAM) could offer a new binder-free consolidation route, since it is capable of processing ceramics in a direct manner without post-processing. However, laser processing of ceramics, especially high performance oxide ceramics, is limited by low thermal shock resistance, weak densification and low light absorptance at room temperature; particularly in the visible or near-infrared range. An extensive review focusing only on LAM (powder bed fusion – laser beam and directed energy deposition) of high performance oxide ceramics is currently lacking. This state-of-the-art review gives a detailed summary and critical analysis about process technologies, part properties, open challenges and process monitoring in the field of oxide ceramics. Improvements in accuracy and mechanical strength are proposed that could open LAM of oxide ceramics to new fields.