金刚石磨粒工具增材制造技术现状及展望

金刚石磨粒工具是工程陶瓷、玻璃、半导体等硬脆材料高效精密加工的重要手段。日益提升的零件制造质量、成型要求和加工效率给金刚石磨粒工具带来了巨大挑战,工具结构改进已成为应对这一挑战的关键,但却给工具制造带来了难题。近年来,增材制造技术因其优异的复杂结构成型能力而备受关注。采用增材制造技术进行金刚石磨粒工具制备也已被业界视为解决复杂结构磨具高效成型的潜在手段并成为研究热点。立足于目前已有的相关研究报道,以光固化成型技术（SLA）、选择性激光烧结技术（SLS）、激光选区熔化技术（SLM）为主,总结现有增材制造技术在金刚石磨粒工具制备方面的研究进展,分析其在制造工艺上的不同特点,并对未来利用该类技术制备金刚石磨粒工具进行展望与建议。     

Geometrical metrology for metal additive manufacturing

The needs, requirements, and on-going and future research issues in geometrical metrology for metal additive manufacturing are addressed. The infrastructure under development for specification standards in AM is presented, and the research on geometrical dimensioning and tolerancing for AM is reviewed. Post-process metrology is covered, including the measurement of surface form, texture and internal features. In-process requirements and developments in AM are discussed along with the materials metrology that is pertinent to geometrical measurement. Issues of traceability, including benchmarking artefacts, are presented. The information in the review sections is summarized in a synthesis of current requirements and future research topics.     

增材制造金刚石工具研究现状及展望

随着金刚石工具朝着形状复杂化、结构精密化、性能高端化等方向发展,常规金刚石制造工艺受成形原理限制较难满足上述要求,亟须寻求新的金刚石工具制造工艺。增材制造是一项新兴的、降三维制造为二维制造的技术,近年来开始应用于复杂结构金刚石工具的制造。本文综述了激光选区熔化、激光选区烧结、立体光固化成形等目前主流增材制造工艺成形金刚石工具的研究进展,详细介绍了3种工艺的成形原理,重点阐述了不同工艺中金刚石与胎体材料的界面结合问题,简要对比了3种增材制造工艺成形金刚石工具的差异。最后,对未来增材制造金刚石工具的研究重点进行了展望。      

Advanced lattice support structures for metal additive manufacturing

Metal additive manufacturing (MAM) of complex parts with overhangs typically requires the use of sacrificial support structures to hold the part during the process. This structures which are built simultaneously with the part, anchors the overhang geometry to the base plate and prevent distortion/curling resulting from thermal stresses. They are necessary, but add constraints to the geometries that the processes can make. The design and selection of support structure can influence the manufacturability of complex metal parts, material and energy utilization, manufacturing time and cost. This study takes a new step on the design and manufacturing a more efficient support through the novel application of lattice structures with very low volume fraction. Experiments were conducted in direct metal laser sintering (DMLS) machine using titanium alloy Ti6Al4V powder. Experimental results revealed that the type of structure, volume fraction and cell size are the main factors influencing the manufacturability, amount of support, and built time of lattice support structures. Lattice supports with very low volume fraction up to 8% were built, saving significant amount of materials used in the support while reducing built time of making MAM parts.     

Rapid manufacturing of metal components by laser forming

This overview will focus on the direct fabrication of metal components by using laser-forming techniques in a layer-by-layer fashion. The main driving force of rapid prototyping (RP) or layer manufacturing techniques changed from fabrication of prototypes to rapid tooling (RT) and rapid manufacturing (RM). Nowadays, the direct fabrication of functional or structural end-use products made by layer manufacturing methods, i.e. RM, is the main trend. The present paper reports on the various research efforts deployed in the past decade or so towards the manufacture of metal components by different laser processing methods (e.g. selective laser sintering, selective laser melting and 3-D laser cladding) and different commercial machines (e.g. Sinterstation, EOSINT, TrumaForm, MCP, LUMEX 25, Lasform). The materials and applications suitable to RM of metal parts by these techniques are also discussed.     

电弧增材制造成形控制技术的研究现状与展望

电弧增材制造是低成本金属零件直接成形的重要研究方向之一。金属零件形貌的成形精度是评判成形质量的一个重要指标。从成形工艺特性、尺寸数学建模、过程控制等角度阐述了电弧增材制造成形控制技术的国内外研究现状;重点总结了基于视觉传感的电弧增材制造闭环控制技术的研究现状;分析了电弧增材制造成形控制技术研究存在的关键问题;提出了未来电弧增材制造成形控制技术的研究内容和发展方向。     

叠层钢板成形模快速制造技术研究

研究了叠层制造工艺的分层处理技术,提出了一种基于EUCLID软件系统的CAD模型直接分层方法,采用等离子切割方法对板材进行切割,板件依序叠合起来后通过胶粘实现层间的粘接。实例表明该工艺为金属模具低成本快速制造提供了有益参考。     

碳钢旁路热丝PAW增材制造成形及组织和性能调控

为了解决电弧增材制造过程中电弧热输入过大导致成形较差、晶粒粗大等问题,以H08Mn2Si碳钢为增材材料,进行了旁路热丝等离子弧(PAW)增材制造成形及组织优化. 首先在单层单道沉积试验中,研究了主/旁路电流比对熔敷成形和热输入的影响;然后进行多层单道沉积试验,分析了不同层间温度下碳钢的成形、微观组织以及硬度;最后对成形良好的增材样件进行了拉伸性能测试. 结果表明,当主/旁路电流比较小时,可以获得表面均匀光滑的熔覆层、母材稀释率可减小至10%;当控制层间温度为较低的温度100 ℃时,增材成形表面质量较好,试样中间稳定区域处的微观组织晶粒尺寸细小,珠光体占比增加,平均硬度最高可达到294 HV;拉伸试验表明其强度性能以及塑性性能在各方向上均匀一致,断裂形式为韧性断裂.     

电弧增材制造控形改性技术研究进展

以电弧作为热源的电弧填丝增材制造技术(WAAM),使用金属焊丝作为熔覆材料,以层间堆焊的方式,可生产出焊接缺陷少、力学性能好的构件,在航空航天、船舶制造、生物医学等领域有重要应用前景。针对电弧增材制造过程中,表面成形精度及组织性能难以准确调控的难点,文中从控制电弧增材表面成形和组织性能两方面综述了国内外研究进展。按照在增材制造时调控手段的介入阶段不同,将调控手段分为在增材过程中的调控、在增材过程后的调控两大类,分别阐述各改善调控工艺技术的原理特点和存在问题及电弧增材制造形性调控未来发展方向。     

铝合金电弧增材制造成形质量研究

基于机器人电弧填丝增材制造成形技术,进行了铝合金零件的成形表面不平整问题的分析及改善方法的试验探究。分析了CMT焊接技术的增材成形效果,以及应用在不同焊道时对成形质量产生的影响;分别探究了起弧与熄弧参数、层间轨迹方式、层间冷却时间等因素对成形质量的影响及改善方法。增材制造翼肋零件中,层间沉积中采用了焊道表面测量,再进行铣削加工的方式,作为进一步探究提高成形质量的试证。结果表明,加大起弧电流、降低熄弧电流,往复的层间轨迹方式及不同层间的冷却时间等方法可以提高零件的成形质量。     

Investigations on heat regulation of additive manufacturing processes for metal structures

By using additive manufacturing processes various powder materials can be melted and geometrically complex parts can be built. There is a need for high energy density to melt a metal powder layer locally. Therefore a laser beam is used to induce the required temperature level. To attain a more homogeneous temperature distribution a heating unit is integrated. To identify the thermal influences a model has been developed and validated by using tungsten carbide. To evaluate the achieved results different quality criteria have been determined. However, both process stability and part quality can be increased by minimizing temperature gradient mechanisms.     

Tool for optimal design of manufacturing chain based on metal forming

Complex approach to the design of manufacturing processes based on considering the whole Life Cycle (LC) of material, including processing and exploitation stages, is presented in the paper. Modelling of the Life Cycle provides possibility to control the final product properties at the stage of manufacturing. It means that required properties and specific behavior of product under exploitation conditions can be obtained by optimization at the stage of material processing. The concept of the design of the entire manufacturing chain is presented in the paper and the application to manufacturing of the connecting part made of modern bainitic steels is proposed.     

高能脉冲精密冷焊的电弧特性和增材制造成形能力

进行了高能脉冲精密冷焊的电弧特性试验和各类零件的增材制造试验,根据脉冲电流和电压波形分析了脉冲电弧的特性,根据堆焊零件的成形情况分析了其增材制造成形能力。结果表明,高能脉冲精密冷焊的输出电流为脉冲方波,产生断续的脉冲电弧;其脉冲时间短,电弧能量密度高,冷却时间长,热输入小,零件变形小;在堆焊成形过程中,工件处于冷态,熔池存在时间短,不会出现焊缝熔池流淌现象,堆焊零件的成形精度高,具有复杂零件的增材制造成形能力;该方法可用于较小的几何形状复杂零件的增材制造,也可用于精密零件的增材制造成形修复。     

伺服主驱动是金属成形机床的必然选择

基于金属成形机床的应用领域,分别就锻造、冲压和钣金制作行业成形机床的主驱动方式伺服化问题作分析展望,帮助金属成形机床制造企业规划发展方向,为用户选购机床提供参考.助力行业提高产品质量,降低生产成本,提高综合竞争力.     

钛/铝异种金属冷金属过渡增材制造

采用TC4和ER2319焊丝直流/变极性冷金属过渡实现异种金属电弧增材制造，通过金相显微镜、扫描电镜、透射电镜、能谱、硬度试验、纳米压痕以及拉伸试验等方法对钛/铝构件界面组织特征与力学性能进行分析.结果表明，在钛合金表面堆积铝合金时，只有少量的钛合金熔化，钛原子扩散到液态铝合金中，形成不同长度的TiAl₃金属间化合物.10 μm左右的反应层在钛/铝界面形成.邻近钛侧的反应层均匀连续，靠近铝合金一侧的反应层呈现长条状或块状.界面反应层的显微硬度介于钛合金和铝合金显微硬度之间.构件的最高抗拉强度为111 MPa.     

稀土在金属增材制造中的应用

增材制造为复杂结构金属材料制备及其组织、性能调控提供了全新的可能。在原材料中添加稀土是改善金属增材制造显微组织和性能的可行方法。本文总结了近期关于稀土在金属增材制造的研究工作,在简要介绍增材制造工艺及组织特征的基础上,着重对稀土在其中的作用进行了综述。同时讨论了目前稀土在金属增材制造应用中需要明确的几个关键基础问题。合理的稀土添加及对应的工艺调整,除了能够优化增材制造金属材料的显微组织和性能,还可能进一步拓展增材制造可加工材料体系的范围。     

激光熔丝增材制造监测与控制系统研究现状

激光熔丝增材制造作为一种定向能量沉积技术,具有很好的发展前景。文中对国内外激光熔丝增材制造监测与控制系统进行归纳概述。现阶段,国内外激光熔丝增材制造常见的监测系统包括结构光扫描系统、红外测温成像系统等,实时监测沉积层高度、熔池状态;常见的控制系统为以闭环控制策略为主的在线反馈送丝速率控制系统、在线反馈激光功率控制系统等,在线监测系统与控制系统协同作用,能够显著优化增材制造工艺、提高成形质量。介绍了包括三维超声波扫描技术、电磁振动监测技术在内的新兴激光熔丝增材制造监测技术。结合激光熔丝增材制造技术的工艺难题对下一代监测与控制系统进行展望。国内外对沉积层高度和宽度、熔池尺寸和温度等监测对象已有较为充分的研究和试验验证,但在沉积过程中,由于激光的高能量密度会造成高温度梯度,因此对沉积过程在线高精度、高质量监测与控制技术的研究变得至关重要。创新点： 激光熔丝增材制造成形精度要求高,同时国内外对该技术的相关工艺、成形原位控制的研究处于起步阶段,对沉积层、熔池偏差的实时监测与控制进行深入研究具有重要意义。     

TIG电弧增材制造5356铝合金微观组织与拉伸性能

为解决电弧连续增材时,由于热积累效应导致堆敷层的塌陷问题,在基板底部加装水冷铝板,制备了水冷断续、水冷连续两种不同工艺的4047铝合金直壁构件,并制备无水冷条件下的增材构件作为对照. 通过对比3种工艺条件下的构件基板热循环曲线、晶粒形貌、抗拉强度、硬度和断后伸长率,研究水冷条件对增材构件宏观形貌、微观组织和力学性能的影响. 结果表明,水冷断续条件能够有效降低热量积累,增材构件侧壁更加平整. 水冷连续条件下增材直壁构件成形最好,两端无塌陷产生,且成形效率最高. 3种增材构件底部晶粒都以等轴晶为主,其余部位都以柱状晶和树枝晶为主. 水冷连续条件下构件的晶粒尺寸最大,水冷断续条件下晶粒尺寸最小. 各增材工艺制备的构件力学性能与ZL102铸造铝合金相当,其中水冷断续工艺制备的增材构件力学性最好.     

增材制造文献

<正>基于开源切片路径规划的机器人电弧增材制造系统/洪恩航, 等. 焊接学报, 2021, 42(11): 65-69.为提高电弧增材制造的灵活性和路径规划可靠性,使用ABB IRB1410工业机器人和Fronius CMT TPS3200焊接电源,通过Python自主编程利用开源切片软件Cura, 成功搭建了电弧增材制造系统,自主开发了电弧增材制造软件,并进行了4043铝合金电弧增材成形.结果表明,     

Determination of optimal motion of tools in metal forming processes by controlled FEM simulation

A method for determining optimal motion of tools in metal forming processes from the finite element simulation is proposed. In this method, the calculated results such as the deforming shape and the stress and strain distributions are monitored in each deformation step of the finite element simulation, and the forming motion of tools is iteratively optimized on the basis of a feedback control referring to the monitored results. The present method is applied to determination of the motion of rolls for forming plates into desired curvatures in plane-strain three-roll bending. Fuzzy reasoning is used to obtain the movement of the top roll in each deformation step, and the effects of the plate thickness and the difference between the desired and the calculated curvatures are taken into consideration. To avoid the delay of the control, the effect of the curvature distribution during bending is included in the fuzzy reasoning. It is shown that decrease in the curvature near both ends of the bent plate in three-roll bending is prevented by the use of the present method.