电镀超硬磨料工艺的改进及参数优化

电镀磨料法是制造超硬磨料工具的常用方法,电镀质量直接影响到电镀超硬磨料工具的寿命和使用性能,而电镀工艺是影响电镀质量的主要因素.文中首先对原有的电镀基础工艺中镀前处理及镀底镍工序进行了改进,提出了镀前处理中增加去毛刺、电化学除油、阳极处理等过程及镀底镍工序中带电入槽和冲击电流的一套新的电镀工艺,并进行了实验研究,结果表明:新的工艺增强了镀层的结合力,提高了电镀质量;其次实验研究了电镀液配方及电流密度、镀液温度、PH值等工艺参数对电镀质量的影响,并得到了优化结果.     

电镀金刚石线锯的制造工艺研究

利用复合电镀法,以直径φ0．3mm的琴钢丝为基体,选取400。的金刚石作为磨料,选用瓦特型镀液,采用埋砂法制造金刚石线锯。利用显微镜测试了镀层厚度,利用体视显微镜观察了线锯形貌。结果表明,上砂电流密度在2．0A／dm2,上砂时间20min时能够获得金刚石磨粒分布均匀、与基体结合力好的金刚石线锯;给出了本实验条件下制造电镀金刚石线锯的最佳电镀工艺参数。     

电镀金刚石丝锥的加工工艺

对电镀金刚石丝锥的加工工艺进行了研究,给出了电镀金刚石丝锥的制造过程,主要包括镀液的配制、金刚石的清洗、上砂槽的制作、试件的镀前处理、预镀、上砂、增厚处理等。通过大量的实验研究和数据分析,重点讨论了电镀工艺参数、主盐浓度对镀层硬度和沉积速度的影响。     

基于球切多面体和光密度的砂轮建模与测量

针对金刚石砂轮磨粒形状的不规则性、尺寸的变化性以及空间位置随机分布的特点,采用基于球坐标的随机点产生的空间平面切分实体的方法,建立更接近实际的虚拟多面体磨粒,并建立金刚石砂轮模型;从类似机床刀具切削刃的磨刃二面角出发,运用仿生物学中光密度以及计算机数字图像处理的方法,提出了基于光密度、积分光密度、平均积分光密度的一种新的砂轮形貌评价方法,并通过试验测量研究了磨刃二面角与积分光密度值之间的关系。研究结果表明,磨刃二面角越大,积分光密度值越大,在0~200之间变化。最后结合砂轮表面面积密度、磨粒平均个数、出刃高度、积分光密度值等参数验证了所建立的虚拟多面体磨粒和砂轮模型的有效性。     

基于MEMS工艺的高能量密度微电磁驱动器

提出了制作高能量密度电磁驱动器的工艺方法。利用微机械(MEMS)工艺在硅片上得到多匝平面线圈和磁芯的掩模图形,接着沉积种子层铜(Cu),然后对种子层进行整体Cu的电铸;当种子层生长到20 μm左右时,剥离硅片表面的镀层并用光刻胶保护磁芯位置的镀层;再用沿线电铸的方法对线圈进行电铸;最后保护制作好的线圈镀层,电铸NiFe合金材料。在10 mm×10 mm×0.38 mm的硅片上,制作出线圈匝数22×2(铜线截面积60 μm×60 μm、总长度达1 164 mm)、NiFe合金磁芯尺寸为3 mm×3 mm×0.2 mm的高能量密度微型电磁驱动器。把这种微型驱动器应用于无阀微泵做驱动实验:通入0.3 A的正弦电流时,微驱动器产生约50 mN的电磁力。实验结果表明:这种型微电磁驱动器在相同的输入功率下,比同类其他微电磁驱动器具有更高的能量密度,能产生更大的电磁驱动力。     

悬浮法制造电镀金刚石线锯的研究

采用悬浮法进行电镀金刚石线锯的实验研究。通过单因素实验方法,借助扫描电子显微镜,研究了复合镀层表面的形貌。结果表明,当工艺参数为金刚石磨粒质量浓度80g/L、分散剂质量浓度2g/L、电镀时间20min、平均电流密度2A/dm2时,能够获得金刚石磨粒分布均匀、符合实际切割需要的电镀金刚石线锯。     

多线往复摇摆线锯切割水晶玻璃的试验研究

利用多线往复摇摆线锯对不同形状的水晶玻璃进行切割试验,测量了不同线速度、不同进给速比条件下的切片表面粗糙度,研究了加工工艺参数对切片表面粗糙度的影响规律.试验结果表明,摇摆运动会有效地降低切片的整体表面粗糙度,线速度的提高有利于减小切片整体表面粗糙度,进给速比的改变对加工表面不同位置的粗糙度影响较大.单位长度材料去除量...     

环形电镀金刚石线锯的研制

研制了一种新型环形电镀金刚石线锯 ,介绍了锯丝基体的制备及锯丝电镀工艺。锯切试验表明该金刚石线锯具有锯切表面质量好、锯切效率高、出材率高等优良性能 ,尤其适合贵重硬脆材料以及各向异性复合材料的切割加工。     

Distribution of diamond grains in fixed abrasive wire sawing process

For over 20 years, wire sawing has been the primary method used for slicing ingots of silicon, sapphire, and silicon carbide into wafer substrates. Fixed diamond wire sawing has recently emerged as an alternative to slurry wire sawing as a means to shorten the time required for slicing and reduce the usage of slurry. The distribution of diamond grains on the wires strongly influences slicing performance in terms of material removal, surface topography, and subsurface damage. However, few studies have investigated this topic. This study established a model with which to simulate the distribution of diamond grains. Simulation results demonstrate that a higher density distribution reduces the rate of material removal because the loading is shared by the abrasives, thereby preventing the grains from penetrating deeply enough into the workpiece to facilitate the removal of material. Lower distribution density was shown to increase the loadings on the abrasives. These results demonstrate the importance of distribution density of diamond abrasives on the wire with regard to slicing performance.     

用表面活化技术提高金刚石与镀层的结合性能

分别用活化处理和未活化处理的金刚石磨粒制备了电镀金刚石工具,通过扫描电子显微镜观察金刚石与镀层的结合状况。对氧化铝陶瓷材料进行钻削加工,对比电镀金刚石钻头在耐用度期间的陶瓷材料去除体积。结果表明,经活化处理的金刚石表面沉积分散的钯质点,工具电镀过程中,在金刚石与镀层间的结合面上形成分散的连接点。应用表面活化技术制作电镀金刚石工具,可使金刚石与镀层形成牢固连接,改善镀层与金刚石的结合性能,其氧化铝陶瓷材料去除体积是未经活化处理金刚石电镀钻头的1.5倍,明显提高了电镀金刚石工具的磨削性能和使用寿命。     

电镀金刚石线锯的制造工艺与使用性能分析

分析了金刚石线锯的电镀工艺过程;研究了金刚石线锯使用时的失效原理及两种失效形式（宏观失效与微观失效）,认为宏观失效以线锯疲劳断裂为主,微观失效则包括金刚石颗粒的磨损脱落和锯丝镀层的磨损。     

Electrochemical slurry jet micro-machining of tungsten carbide with a sodium chloride solution

Electrochemical slurry jet micro-machining (ESJM) is a new non-conventional process that couples abrasive slurry jet machining (ASJM) and electrochemical jet machining (ECJM) concurrently. A micro-jet of abrasive particles and electrolytic solution is made to impinge on the target while applying a DC potential between the jet nozzle and the workpiece. ESJM can be used to remove material that is difficult to machine through a combination of erosion, corrosion and synergistic effects. This study focuses on ESJM of tungsten carbide (WC) using a pH-neutral NaCl electrolyte rather than an alkaline solution which is more commonly used in the electrochemical processing of WC. For the studied process parameters, it was shown that the erosion due to ASJM alone was not able to erode the WC, and that the corrosion under ECJM was slow and produced unacceptably wide channels. The combined ESJM process however, was found to involve erosion of the developed oxide layer and subsequent exposure of un-corroded WC, leading to a much higher machining current density, corrosion rate, and machining localization than using ECJM alone. It was also found that the total abrasive kinetic energy, working voltage and solution concentration strongly affected the machining current density, material removal rate and aspect ratio (depth to width ratio). The results indicate that ESJM has a high potential to machine difficult-to-cut metals efficiently and economically.     

喷射电沉积制备泡沫镍实验研究

提出了一种制备泡沫镍的新方法——喷射电沉积法。该方法基于高电流密度容易生成多孔枝晶沉积层的原理,制备了具有简单形状的泡沫镍试样。研究了相关工艺参数（电解液成分、电流密度、电解液喷射速度等）对泡沫镍试样的微观结构影响,结果表明：多孔沉积层的孔壁由枝晶构成,孔壁围成了孔洞,孔隙率在30%～70%之间;随着电流密度的增大,泡沫镍的孔隙率逐渐减小;随着电解液喷射速度的提高,泡沫镍的孔隙率逐渐增大。     

Sawing performance comparison of brazed and sintered diamond wires

Great attention has been paid on fabricating diamond wire by using the brazing diamond because of its strong chemical bonding strength and controllability of grits distribution. Although several serving performances of brazed diamond wire have been reported, seldom do these studies refer to its process characteristics. Sawing performances of a brazed diamond wire are investigated and compared with those of a sintered diamond wire on a wire saw machine. The surface topographies of beads selected from the two wires are micro observed before sawing. The sawing tests are carried out in constant feed rate feeding(CFF) and constant normal force feeding(CNFF). In CFF test, sawing force, power, and the cut depths of positions on contact curve are measured. Then, coupled with the observations of beads topographies, sawing force and its ratio, relations of power against material removal rate, and contact curve linearity are compared and discussed. In CNFF test, the sawing rates of the two wires are investigated. The results indicate that the brazed wire performs with lower sawing force(less 16% of tangential force and 28% of normal force), more energy efficiency(nearly one-fifth of sawing power is saved), at a higher sawing rate (the rate is doubled) and with better contact curve linearity as compared with the sintered wire. This proposed research experimentally evaluates the sawing performances of brazed diamond wire from the aspect of process parameters, which can provide a basis for popularizing the brazed diamond wire.     

Optimising the Lithographic Patterning Effect in an Acid Copper Electroplating Process

The effects of the average cathodic current density, electrode separation, and the active area density on the workpiece-level plating thickness variability were studied by factorial experiments for an acid copper pattern electroplating process. All the three parameters and the current densityXelectrode separation interaction were found to be significant, and an 8- term first-order prediction model was constructed and verified experimentally. The minimum variability achievable was found to increase with the active area density contrast over the board surface, and was explained by the scattering effect of the density contrast on the average plating thickness. A subsequent verification run using a simple circuit pattern showed that a composite parameter involving the overall active area density, the continuum area and the number of density contrasts, was appropriate. The possibility of further reducing the workpiece level variability by investigating the interaction effect between the overall active area density and the density contrast of the substrate was suggested.     

Micro fabrication using electro deposition and ultrasonic acoustic liquid manipulation

We report improvement of the acoustic liquid manipulation (ALM) assisted electroplating process for micro fabrication. We refined the process and were able to achieve a plated dot size of 0.031 inches, using highly backed ultrasonic transducers. This potential tool-less fabrication (TLF) technique will reduce the need for masking and can be used for rapid prototyping of microstructures. We report the plating of copper on steel plates. An ion-depleted layer is formed at the cathode when the electroplating process starts, thus forming a natural mask. A fine stream of fresh electrolyte formed by acoustic streaming by an ultrasonic transducer is directed to refresh the ion-depleted layer at the cathode. This causes the plating process to continue at a localized point. The thickness of the plating increases with time. The process can be automated by mounting the transducer assembly on a three dimensional control system. This will enable rapid fabrication of three dimensional micro structures and shapes by the direct writing method.     

弯曲钢丝绳股内钢丝张力变化仿真与实验

以1+6型钢丝绳为研究对象,应用有限元方法进行仿真分析,得到绳股内各丝张力随钢丝绳-天轮接触弧长与钢丝绳捻距比值的变化规律,并通过实验对仿真结果进行验证。运用灰色关联度分析法对仿真结果和实验结果进行对比分析,阐述了钢丝张力变化的周期性规律。研究结果表明：当钢丝绳-天轮接触弧长等于钢丝绳捻距一半的奇数倍时,绳股内钢丝弯曲张力差值较大;当钢丝绳-天轮接触弧长等于钢丝绳捻距一半的偶数倍时,绳股内钢丝弯曲张力差值较小。     

金刚石薄膜磁性研磨抛光研究

表面粗糙度是影响金刚石薄膜广泛应用的主要因素,选择一种合适的抛光方式可以大幅度降低表面粗糙度,以加速其商业化应用的进程。文中针对内孔金刚石薄膜,提出了一种新的抛光方法——磁性研磨抛光。实验结果表明,可有效除去薄膜晶粒外缘的尖角,而且不会造成涂层的损伤,不影响涂层附着力,是一种温和的抛光方法,可以达到比较理想的抛光效果,采用磁性研磨抛光的金刚石涂层铜杆拉丝模,工作寿命比硬质合金模具提高8-10倍,满足了铜杆拉丝对模具内孔表面光洁度的更高要求。     

基于有限元模拟的铜包铝线拉拔参数优化

为研究拉拔参数对铜包铝线质量的影响,运用有限元方法对金刚石涂层拉拔模具拉拔铜包铝线的过程进行了模拟仿真,研究了拉拔过程中模具的应力分布情况,分析了压缩率对铜包铝线残余应力分布均匀性的影响规律。利用正交实验法研究了拉拔参数(工作锥半角α,定径带长度L,过渡圆弧半径R,压缩率β)对铜包铝线尺寸精度和残余应力分布均匀性的影响,获得了最佳拉拔参数(α=6°,L=4.5 mm,R=3 mm,β=1.82%)和各因素对分析指标的影响规律。并在此基础上对优化方案进行了模拟,结果证明了正交实验对拉拔参数优化的有效性,对金刚石涂层拉拔模具的设计及高质量铜包铝线的拉制有重要的指导意义。     

Research on electrochemical discharge-assisted diamond wire cutting of insulating ceramics

Insulating ceramics are difficult to cut because of their high hardness and brittleness properties. This research proposes an electrochemical discharge-assisted diamond wire method for cutting insulating ceramics. The high temperature generated from electrochemical discharge facilitates the spalling of ceramics by the moving diamond wire. Experimental results showed that the material removal rate (MRR) of the new cutting method increased compared with the conventional diamond wire cutting process. Besides, electrochemical discharge had limited influence on the surface roughness and the wear of diamond wire. Additionally, the influence of the process parameters (DC voltage, wire speed, and counterweight mass) on the MRR and surface roughness was analyzed through experiments. The results showed that the MRR and surface roughness initially increased and then decreased with the increasing DC voltage; however, the variation was little. The higher wire speed resulted in an increased MRR and had little influence on the surface roughness. The MRR and surface roughness increased with the increasing counterweight mass.