飞秒激光切割与微细电阻滑焊组合制备三维金属微结构

提出了一种采用飞秒激光切割结合微细电阻滑焊制备3D金属微结构的工艺方法(微型化双工位金属箔叠层制造法,(Micro-DLOM)),并通过制备具有复杂形状的3D微型腔模具验证了该工艺方法的可行性。首先,以厚度为10μm的0Cr18Ni9不锈钢箔为基材,在110mW的飞秒激光功率、100μm/s的切割速度和0.75μm的切割补偿量下获得二维微结构,并分析了激光功率和切割速度对切割精度的影响;然后,利用微细电阻滑焊对多层二维微结构进行热扩散焊接,通过多层二维微结构的叠加拟合形成具有曲面特征的微型腔,并对焊接区进行了X射线衍射(XRD)分析。分析发现:微细电阻滑焊所产生的热量仅使焊接区主要物相的相对含量发生了变化,而没有使该区域产生新的物相。与UV-LIGA工艺相比,本工艺可以加工具有自由曲面特征的三维微结构,并且单层钢箔越薄,成形精度越高;与飞秒激光分层平面扫描烧蚀工艺相比,本工艺仅需切割每层二维结构的轮廓,提高了成形效率;与微细电火花加工工艺相比,虽然所成形的微型腔表面粗糙度相对较差,但却省去了制备微电极的工艺步骤,并且不存在微电极工作过程中的损耗问题,所以可以加工深宽比不受限制的微模具。     

Fabrication of 3D metal micro-mold based on femtosecond laser cutting and micro-electric resistance slip welding

This paper proposes a novel fabrication process based on femtosecond laser cutting and micro-electric resistance slip welding to address the bottleneck presented by ultraviolet–Lithographie, Galvanoformung, Abformung combined with micro-electroforming, in which micro-molds are usually fabricated with vertical wall structures. At first, 10-μm thick 0Cr18Ni9 stainless steel foils were cut by femtosecond laser to obtain several single-layer graphics which were then joined by micro-electric resistance slip welding. The slip welding process formed a 3D micro-structure and the weld zone of micro-structure was tested by the X-ray diffraction (XRD). The XRD results show that the phases of weld zone remain unchanged, but that the phase content slightly changes. Finally, a 3D metal micro-structure mold was processed under 110 mW femtosecond laser power, 0.1 mm/s cutting speed, 0.21 V welding voltage, 10 ms welding time, 0.2 MPa welding pressure, 0.5 mm bar electrode diameter, 160 time’s slip welding discharge, which proves that the forming process could be a useful method for the production of 3D micro-molds.     

逐层微细电阻滑焊工艺制备三维微结构

采用飞秒激光切割和微细电阻滑焊组合的方法制备了高深宽比的三维微结构。为了提高每层二维微结构的叠加精度和连接强度,用逐层微细电阻滑焊对每层二维微结构进行滑焊以获得较好的工艺参数。对上述工艺参数所制备的微结构进行了抗剪切能力测试,测试结果显示:随着滑焊放电次数的增加,微结构的极限剪切力由8.04N逐渐增加至65.97N。而后,通过能量分散光谱仪(EDS)对电极的沉积效应进行了研究。最后,在120mW的飞秒激光,50μm/s的切割速度,0.21V的焊接电压,0.2MPa的焊接压强,100ms的预压时间,10ms的焊接时间以及160次的滑焊放电次数等工艺参数下制备了基本尺寸为50μm×50μm的微方孔阵列以及微齿轮结构。实验结果表明:通过逐层微细电阻滑焊制备的微结构表面质量良好,各层微结构之间叠加较好,显示逐层微细电阻滑焊可以较好地保证三维微结构中各层二维微结构的连接强度和叠层精度。     

Study on tungsten electrode deposition effect of 3D metal micro-mold during laminated slip welding

3D metal micro-mold fabricated through the micro double-staged laminated object manufacturing process is formed via stacking and fitting of multi-layer 2D micro structures. In this paper, it is suggested that micro-electric resistance slip welding technology be adopted to optimize the connection of micro structures in 3D metal micro-mold. Moreover, the deposition effect of tungsten electrode which was formed on the micro-mold surface and produced during micro-electric resistance slip welding is also studied. Firstly, the temperature field of electric resistance slip welding was simulated by ANSYS software and the maximum temperature in the slip welding area is 1,219 °C when the number of slip welding discharge is 160, which is far lower than the melting point of tungsten electrode material (3,410 °C). Hence, bulk tungsten will not shed during slip welding; however, the wear of the tungsten electrode will be deposited on the surface of the micro-mold in micro-particle shape. Secondly, the influence of slip welding discharge and surface roughness of tungsten electrode on tungsten deposition effect is studied and the study shows that: the content of tungsten within the slip welding area increases gradually as the number of slip welding discharge increases, and decreases gradually as surface roughness of tungsten electrodes increases. Finally, under 160 time’s slip welding discharge and using tungsten electrodes (0.5-mm diameter and 0.12-μm surface roughness), the 3D metal micro-molds which contains 0.4 % tungsten in slip welding area and has a good quality surface was obtained.     

UV-LIGA和微细电火花加工技术组合制作三维金属微结构

为了制作三维金属微结构,研究了UV-LIGA和微细电火花加工技术组合的工艺方法。使用UV-LIGA技术制作了准三维金属微结构,然后,对该微结构进行微细电火花加工制作三维金属微结构。使用提出的方法制作出了局部为梯形凸台和锥形凹槽三维微结构的镍模具,给出了梯形凸台和锥形凹槽的尺寸。分析了微细电火花加工中放电参数对表面粗糙度的影响,在工作电压为65V,标称电容为100pF时得到了Ra为0.08μm的微细电火花加工表面。研究结果表明,使用该方法可实现三维金属微结构的制作;通过减小工作电压和标称电容的方法可降低微细电火花加工的表面粗糙度。     

基于DEFORM-3D的金属锯切过程力能仿真研究

运用金属切削力学理论与方法对圆锯机锯切过程的力能参数进行理论计算,得到锯切过程的平均锯切力和平均锯切功率。基于DEFORM-3D软件建立金属锯切有限元模型,仿真得到平均锯切力值,与理论计算得到的平均锯切力误差为3.5%;实验得到圆锯机主电动机锯切过程中的平均锯切功率值,与理论计算得到的平均锯切功率误差为3.8%。力能参数理论计算、DEFORM-3D有限元仿真、实验测试数据对比,表明用DEFORM-3D有限元研究金属锯切机理是一种可行的方法,为锯切机理的研究提供了参考。     

三维激光切割在机械加工机床中的集成研究

研究了如何在机械加工的五轴机床中集成三维激光切割功能,并开发了三维激光切割控制软件。围绕该840Dsl数控系统进行三维激光切割系统硬件集成设计以实现激光切割过程中各加工控制部件自动化控制;并针对三维激光切割系统硬件结构,控制软件进行模块化设计,包括离线编程模块、加工控制模块设计以及激光切割工艺数据库等3大模块。通过在五轴龙门机床上调试验证,该控制软件能够很好实现三维激光切割控制功能。该研究将激光切割功能集成在传统机械加工机床中,这将提高机床的利用效率,同时简化工件装夹流程,提高加工效率。该研究对机械加工机床功能扩展有较大的参考价值。     

Fabrication of PCD micro cutting tool and experimental investigation on machining of copper grating

This paper presents an investigation on machining of copper grating. Ultra-hard polycrystalline diamond (PCD) micro cutting tools were designed and machined, especially focused on fabricating micro channel arrays characterized by excellent quality with high efficiency. Micro cutting experiments of copper grating were carried out using the self-developed PCD micro tools, and the effect of width of cut, feed per tooth, and spindle speed on dimensional accuracy and burr formation was investigated. Additionally, optimum combination of processing parameters was obtained. As a result, a complete copper grating with superior dimensional accuracy and minimum top burrs was machined by employing the self-developed micro cutting tools under the optimal parameters.     

阀门密封面金属覆层激光焊接的研究

介绍了金属覆层激光焊接技术在阀门密封面上的应用。给出了激光焊接过程的工艺条件和设备参数及其试验鉴定结果。     

薄壁不锈钢圆管三维激光切割夹具设计

设计夹具解决了三维激光切割薄壁不锈钢圆管时,采用直接装夹方式产生装夹变形、翘曲变形及定位精度低的问题,而且还可以提高薄壁不锈钢圆管的切割质量和加工效率。     

材料切削性能的模糊综合评判

介绍了一套材料加工参数智能推理系统的研究。重点讨论了模糊理论在该系统中的运用，采用模糊综合评判、模糊聚类原理，根据用户输入材料的物理机械性能，快速确定材料的切削加工性能。将材料按切削加工性能等级分类可简化材料切削参数推理，有利于新材料切削参数的确定。     

Crater and flank wear resistance of cutting tools having micro textured surfaces

We have proposed cutting tools with various textured surfaces to increase cutting tool life. Our previous studies have developed cutting tools having periodical stripe-grooved surfaces on their rake face formed using femtosecond laser technology, which displayed high crater wear resistance in cutting of steel materials. In this study, the mechanism for suppressing the crater wear on the tool surface and the relationship between texture dimensions and wear resistance were investigated to provide a guideline for developing tools with textured surfaces. Furthermore, we newly introduced the textured surfaces into a flank face of cutting tools to improve flank wear resistance. Face milling experiments on steel materials exhibited that the newly developed tool having the textured flank face significantly reduced the flank wear. Moreover, the influences of texture dimensions and cutting conditions on the flank wear resistance were also discussed.     

三维打印成形的金属零件快速制造技术

阐述三维打印快速成形技术的类型及特点,对利用三维打印技术进行金属零件快速制造的几种工艺及其特点进行了对比分析.     

基于激光多普勒技术的微悬臂梁机械特性的测量

介绍了一种微悬臂梁离面运动测试系统。结合显微激光多普勒技术,分析了用于间接测量微悬臂梁机械特性的方法,采用虚拟仪器技术建立控制系统,编辑器件激励和数据采集、处理软件,实现了对微悬臂梁的动态特性和杨氏模量、弹性系数等机械特性的测量。最后利用该测试系统对矩形、三角形微悬臂梁杨氏模量进行了实验研究,并计算了两种微悬臂梁的弹性系数。经实验证明,用该方法测量悬臂梁机械特性得到的弹性系数和杨氏模量误差小于7．5％。     

基于三维激光扫描仪的地形变化监测

提出了应用三维激光扫描仪监测地形变化的方法.介绍了仪器原理、结构、用途和观测方案.用球形标志法和DEM求差法提取地形变化信息.实验表明,该方法具有很高的精度和分辨率,可以应用在灾害评估、矿产量估计和工程量计算等方面.     

A seam-tracking laser welding platform with 3D and 2D visual information fusion vision sensor system

In this paper, a laser welding experimental platform for narrow and burred seam welding (with seam width less than 0.1 mm) of complex three-dimensional (3D) surface based on eight-axis machine tool is introduced. A novel vision sensor system (which is named as HUST-SM) which based on visual information fusion of 3D and two-dimensional for detecting the narrow and burrs welding seam is also presented. Several experimental tests are applied to verify the features of this platform and the HUST-SM vision sensor system. Experimental results show that the vision sensor system has high precision and resolution for obtaining narrow seam information. The narrow seam of space curve welding tests demonstrates that the narrow seam welding can achieve high finish quality.     

Fabrication of 3D submicron to micro textured surfaces using backside patterned texturing (BPT)

This work presents a novel fabrication method for submicron to micro size textures on flat surfaces using the backside patterned texturing (BPT). The proposed method utilizes the pre-fabricated macro-features on the backside of work material, and thereafter the front side is face turned with a single point diamond tool to generate textured surfaces. Different from existing texturing methods, BPT produces textured surfaces from submicron to micro scale without any external gadgets such as vibration assisted machining or synchronized tool-spindle motion. The miniature feature arises on the diamond turned surface due to the induced residual stresses when the specimen is unleashed from the machine. To demonstrate the efficacy of the method, a series of machining experiments were conducted to fabricate various types of freeform surface textures like water-drop freeform, cylindrical freeform surfaces, etc. The fabrication methodology of different sizes of bumps with precisely controlled surface quality is illustrated. The texture profiles comprising the deformation height from hundreds of nanometer to few micrometers with mirror surface quality were successfully fabricated on the diamond machined surface. The experimental results suggest that the pre-fabricated pattern, workpiece thickness and machining condition play a critical role to determine the final shape and geometry of generated textures.