微细孔电解加工控制方法及试验研究

基于微细电解加工的特点，介绍了一种微细电解加工系统。该系统能够将加工间隙控制到几微米到几十微米的范围内。根据电解加工以离子形式对材料去除的特性，进行微细电极、微细群电极的制备研究，并将其用于微细孔、群孔的加工中。试验分析了各工艺参数如电压、溶液浓度、加工间隙、进给速度等对微细孔电解加工精度的影响。结果表明，微细电解加工的侧面间隙随着加工电压的降低、溶液浓度的减小、脉宽变窄和初始加工间隙的减小而减小，改善了加工的定域性，加工精度得到提高。     

基于线电极原位制作的微细电解线切割加工

微细电解线切割加工是一种微细加工新方法。从理论上分析了线电极直径大小对微细电解线切割加工精度的影响,提出了原位制作微米尺度线电极的方法,并制作出直径5μm的钨丝线电极。通过电解线切割加工试验,加工出缝宽为20μm左右的微型桨叶结构和曲率半径在1μm以下的微细尖角结构。     

振动进给对微尺度群缝电解加工过程的影响

为精确控制振动进给运动,研制了多参数可调的电解加工振动进给装置系统。通过对工具阴极振动进给方式对电解加工间隙内电解产物排出、电解液流场稳定性影响的分析,以剃须刀网罩上的微尺度阵列群缝的电解加工为研究对象开展了系列工艺试验,研究了振动进给的运动参数对微尺度群缝的平均缝宽、侧壁锥度的影响,据此优选了工艺参数,并成功批量加工出了缝宽为0.26mm、侧壁锥度小于5%的微尺度阵列群缝。试验结果证明,振动进给能够有效提高微尺度群缝的电解加工精度和加工过程稳定性。     

基于电场仿真的微尺度群缝电解加工技术研究

以静刀盖微尺度群缝电解加工为研究对象,针对工艺试验过程中群缝成形规律难以掌握,试验参数修正周期长的问题,采用COMSOL软件对单缝成形过程进行了电场仿真,并以电场仿真参数结果进行工艺试验,加工出平均缝宽0.27mm,侧壁锥度为0.12的群缝结构。电场仿真与工艺试验结果对比表明,电场仿真方法减少了工艺试验中大量试验参数的修正工作,缩短了电解加工工艺试验周期,且电场仿真与工艺试验单缝最大形状误差在0.03mm以内。     

微尺度弧形群缝电解加工试验研究

精密电解加工是剃须刀网罩上微尺度阵列弧形群缝的首选加工工艺,为提高电解加工精度和加工过程稳定性,基于电场分析,优化了工具阴极凸起宽度、凸起高度关键尺寸的设计;基于对流场的数值分析,优化设计了电解液流道结构,优选了电解液进出口压力参数,消除了流道内可能存在的缺液区和流线交叉区域,并据此研制了专用工装夹具。通过工艺试验,研究了端面初始间隙、平均电压,进给速度等关键工艺参数对群缝缝宽的影响。在研制的数控电解加工设备上加工出了缝宽0.24 mm的弧形群缝,且群缝的曲线形状精度高,加工过程稳定,已能够满足批量生产的需要。     

电化学腐蚀法制备微细群圆柱

提出了微细群圆柱结构电化学腐蚀加工法及其形状和尺寸控制方式。根据电化学腐蚀基本原理,通过有限元分析计算群圆柱电化学腐蚀加工过程中的电场分布,优化设计阴极形状。开展了电化学腐蚀法制备微细群圆柱结构的工艺试验,获得了良好的试验结果。     

旋转电极电解电火花切割玻璃微结构试验研究

针对高深宽比非导电硬脆材料(如石英玻璃和陶瓷)微结构的加工需求,对微细电解电火花切割加工方法进行了深入研究。首先,提出了使用旋转螺旋微工具电极的电化学放电切割方法,并对切割缝宽模型进行了讨论;其次,对旋转螺旋电极电解电火花切割加工工艺进行了深入的试验研究,试验研究了加工电压、脉冲频率、占空比和主轴转速这些关键工艺参数对切割加工精度的影响。实验结果表明,缝宽随着施加电压和占空比的增加而增加,随着频率、主轴转速和进给速率的增加而减小。最后,通过优化后的参数成功加工出缝宽为135μm的微缝阵列、复杂的封闭微结构以及深宽比达6∶1的微图形结构。由此表明该方法是一种可有效加工高深宽比绝缘硬脆材料微结构的新工艺。     

微细电解线切割加工的基础研究

基于电化学原理，讨论了纳秒脉冲电流微细电解线切割加工的机理，建立了微细电解线切割加工数学模型；采用电化学腐蚀原理对微米尺度线电极进行在线制作，建立了微细电解线切割加工试验系统，并进行了微细电解线切割加工试验，切割出带90°直角的微结构，其切缝宽度为30μm。     

脉冲电解加工技术在精微加工领域中的新发展

介绍了高频、窄脉冲成形加工技术新的研究成果，考察了国外微细加工技术的新发展状况，结果表明：精密窄脉冲电解加工近年来向提高频率、缩短脉宽方向发展；大电流、高频、窄脉冲电流源加工精密复杂型腔、型面的新工艺及新电源已投入模具、叶片的试生产中，显示出良好的技术经济效果，成形精度可达0．05mm；近期国外又发展了数百兆赫、数百纳秒级微小电流加工数十微米级零件的微细加工技术，开拓了电解加工用于微细加工的新领域，显示了脉冲电解加工巨大的发展潜势。试验研究表明，随着频率的提高、脉宽的变窄，引起阳极集中蚀除能力进一步加强，加工间隙进一步缩小，最终导致加工精度相应提高。所研制的1000A、20kHz矩形波电流源的脉冲前沿上升时间迭微秒级，快速短路保护时间仅为数十微秒级。     

微细电火花加工用晶体管脉冲电源的研究

在传统晶体管脉冲电源的基础上，研制开发了一种适用于微细加工的晶体管脉冲电源，这种脉；中电源可以满足微细加工中粗加工、精加工的不同需要，可实现最小脉宽为50ns的放电电流。通过微细孔加工实验，对所开发的晶体管脉冲电源的加工特性与传统的RC脉冲电源进行了分析比较，实验结果表明前者的加工效率约为后者的2～6倍。     

Tip radius effect of AFM probe on K4Nb6O17·3H2O nanosheets groove machining accuracy

This paper presents a technique for groove machining of potassium niobate nanosheets using an atomic force microscope (AFM). Groove machining operations are performed using super sharp silicon (SSS) probes. The tip radius of these probes is less than 5 nm and is one-third that of a conventional silicon (Si) probe. The results obtained using these probes are compared with those obtained using a Si probe, in order to examine the tip radius effects of the AFM probe on groove machining accuracy, i.e., coarseness of the machined groove. These results show that the degree of coarseness of the machined groove for varying machining loads with the SSS probe was much worse than that with the Si probe. Thus, groove machining with the SSS probe was more difficult to control with varying machining loads. We propose a groove fabrication model that considers the stochastic energy and difference in tip radius of the AFM probe. Using our groove fabrication model, changes in the coarseness of the machined groove for varying machining loads can be predicted.     

微槽激光电解组合微加工研究

微槽结构作为微型结构的基本单元,具有增加散热面积、存储润滑剂和减少阻力等功能,多用于大热流密度器件的散热或表面润滑,但其存在加工尺寸小、精度要求高以及加工难度大等问题.为了实现微槽的高效高精度加工,提出了一种激光电解组合微加工方法,并搭建了纳秒激光加工装置和数控微细电解加工装置;利用激光烧蚀快速加工出微槽结构的基本形貌...     

射流电解加工微小窄槽的工艺研究

在电液束加工小孔的基础上,开发了一种新的小尺寸三维形体射流电解加工工艺。用射流电解进行窄槽加工,并通过正交试验的方法研究加工过程中电压、占空比、频率、靶距等加工参数对槽形的影响。发现工件一旦进入射流形成的加工区就会被均匀的加工。用圆形的玻璃喷嘴加工后的槽的横截面趋于椭圆,这相当于一把椭圆球铣刀的切削效果。电压对去除量有重要的影响,但在450~550 V的范围内变化时去除量较为稳定。试验表明,占空比在50%~90%之间变化时去除量较为稳定。     

INDUCTION-HEATED TOOL MACHINING OF ELASTOMERS—PART 2: CHIP MORPHOLOGY, CUTTING FORCES, AND MACHINED SURFACES

The induction-heated tool and cryogenically cooled workpiece are investigated for end milling of elastomers to generate desirable shape and surface roughness. Elastomer end milling experiments are conducted to study effects of the cutting speed, tool heating, and workpiece cooling on the chip formation, cutting forces, groove width, and surface roughness. At high cutting speed, smoke is generated and becomes an environmental hazard. At low cutting speeds, induction heated tool, if properly utilized, has demonstrated to be beneficial for the precision machining of elastomer with better surface roughness and dimensional control. Frequency analysis of cutting forces shows that the soft elastomer workpiece has low frequency vibration, which can be correlated to the surface machining marks. The width of end-milled grooves is only 68 to 78% of the tool diameter. The correlation between the machined groove width and cutting force reveals the importance of the workpiece compliance to precision machining of elastomer. This study also explores the use of both contact profilometer and non-contact confocal microscope to measure the roughness of machined elastomer surfaces. The comparison of measurement results shows the advantages and limitations of both measurement methods.     

INDUCTION-HEATED TOOL MACHINING OF ELASTOMERS—PART 2: CHIP MORPHOLOGY,CUTTING FORCES,AND MACHINED SURFACES

ABSTRACT

The induction-heated tool and cryogenically cooled workpiece are investigated for end milling of elastomers to generate desirable shape and surface roughness. Elastomer end milling experiments are conducted to study effects of the cutting speed, tool heating, and workpiece cooling on the chip formation, cutting forces, groove width, and surface roughness. At high cutting speed, smoke is generated and becomes an environmental hazard. At low cutting speeds, induction heated tool, if properly utilized, has demonstrated to be beneficial for the precision machining of elastomer with better surface roughness and dimensional control. Frequency analysis of cutting forces shows that the soft elastomer workpiece has low frequency vibration, which can be correlated to the surface machining marks. The width of end-milled grooves is only 68 to 78% of the tool diameter. The correlation between the machined groove width and cutting force reveals the importance of the workpiece compliance to precision machining of elastomer. This study also explores the use of both contact profilometer and non-contact confocal microscope to measure the roughness of machined elastomer surfaces. The comparison of measurement results shows the advantages and limitations of both measurement methods.     

剖析轴类零件中精密槽的编程与JJnT

以轴类零件中常见的切槽加工为例,通过数控车使用G01指令切槽加工的编程方法与加工方法的描述,结合数控车床尺寸精度的控制方法,分析槽底尺寸和槽宽尺寸的精度控制方法。     

钛合金深窄槽可控振动辅助电解加工试验研究

为提高TB6钛合金深窄槽电解加工精度,基于电场仿真分析方法,研究了不同加工方式深窄槽侧壁电流密度和电化学溶解速度分布规律,并采用工艺试验方法对持续进给、振动进给、脉冲与振动耦合3种加工方式进行对比研究。试验结果表明：振动频率和持续进给速度固定时,提高振幅能够显著降低槽宽标准差,提高深窄槽加工一致性;持续进给速度相同时,脉冲与振动耦合的平均槽宽和槽宽标准差均较小,加工精度更高。采用脉冲与振动耦合加工方式,深窄槽入口处平均槽宽为2.62 mm,沿深度方向平均槽宽为2.73 mm,入口处槽宽标准差为0.05 mm,沿深度方向槽宽标准差为0.03 mm。     

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.