放电通道的微观模拟及其物理性能研究

电火花加工机理研究的相对滞后在一定程度上制约了电火花加工技术的进一步发展;放电通道中带电粒子的运动特性、电磁特性及振荡性的研究是电火花加工机理研究中的重要组成部分.运用粒子模拟方法,对电火花加工放电通道中等离子体柱的形状及放电通道的电流、电磁特性进行了仿真模拟,仿真结果发现当放电通道达到平衡状态时,放电通道的负极为喇叭口形,中部为腰鼓形.最后分析了造成放电通道振荡的原因以及对放电加工效果的影响.     

硬质合金模具放电加工工艺参数探讨

根据电火花放电加工原理,对电火花线切割机床和电火花成型机床放电加工硬质合金模具６试验结果进行详细分析得出最佳放电加工参数。     

超声频间隙脉放电加工的放电特性和加工特性的理论研究

本文对超声频间隙脉冲放电加工的放电特性和加工特性进行了详细的理论研究。研究结果表明：超声频间隙脉冲放电加工的放电电流和电压特性与一般的电火花加工是不同的。并且加工效率高于普通电火花加的效率，而其加工表面粗糙和加工形状精度接近于普通电火花和加工的表面粗糙度和加工形状精度。     

电参数对钛合金放电诱导可控烧蚀车削加工的影响研究

设计了基于放电概率的诱导烧蚀电极伺服控制系统,通过优化实验,设定其放电概率为80%,并在此基础上分析了脉冲宽度、脉冲间隔、峰值电流等电参数对加工的影响。结果表明:正极性加工时,峰值电流对加工效率的影响最大。通过选取优化参数,与常规电火花车削对比表明:放电诱导可控烧蚀车削的材料加工效率是常规电火花车削的27倍,电极相对损耗仅为常规电火花车削的80%。     

基于Labview软件的电火花加工放电状态检测

电火花加工中放电状态的检测对加工稳定性、加工效率具有重要的意义.以电火花放电状态分类为基础,使用Labview软件编写识别放电状态的程序,对采集到电压和电流数据进行了分析.实验证明,程序统计结果与实际结果较吻合,这为建立电火花实时控制系统提供了有效的检测手段.     

压电自适应脉冲式电火花加工放电通道粒子流场模拟

压电自适应脉冲式电火花加工是一种新型电火花加工方法.通过分析放电通道的形成过程,采用PIC/MCC相结合的方法,对压电自适应脉冲式电火花加工放电通道进行了微观粒子模拟,得到带电粒子(电子和正离子)在放电通道内的分布规律.仿真结果显示放电通道位形呈腰鼓状,通道中任意横截面带电粒子的空间分布符合高斯分布,为电火花加工温度场...     

电火花加工放电介质的研究

通过对电火花加工放电通道中等离子体柱的形状和放电通道的电流、电磁特性进行分析,并对电火花加工中不同介质的加工性能进行对比和总结,提出电火花加工介质的技术研究方向应符合绿色制造和资源的可持续发展的理念。     

加工间隙对电火花加工质量影响的分析

在电火花加工中要降低各种干扰因素的影响,确保加工质量和稳定的加工过程,放电间隙的一致性是非常重要的一个技术指标。详细分析了影响放电间隙状态变化的因素,提出了维持放电间隙大小一致性的相应措施,对进一步改善电火花加工质量具有一定的参考价值。     

超声电火花复合加工在模具制造中的应用

电火花加工技术能对高硬度、高强度金属材料加工,但存在加工效率低和加工表面质量不好的缺陷。通过对超声电火花复合加工研究,探讨了放电参数对加工速度影响的规律,指出超声电火花复合加工工艺可弥补电火花加工在加工效率及质量方面的不足,将会对模具型腔、型芯的制造产生重要影响。     

难加工材料的电火花加工脉冲电源研究

针对目前航空、航天等领域中日益广泛应用的硬质合金等材料出现的切削加工困难、电加工蚀除速度慢的问题,设计了带有放电爆炸力的电火花加工脉冲电源。建立了电火花放电加工的热力学传导模型,通过有限元仿真方法得出具有放电爆炸力的单次脉冲能够明显提高难加工材料蚀除量的结论。加工对比实验证明具有放电爆炸力的脉冲电源能够实现高效、稳定的放电加工。     

Optimization of back bead geometry in the PMAG-TIG twin arc hybrid root welding process using grey based Taguchi method

This study investigated multi-response optimization of the pulse metal active gas-tungsten inert gas( PMAG-TIG) twin arc hybrid root welding process for an optimal parametric combination to yield favorable back bead geometry of welded joints using grey relational analysis and Taguchi method.Eighteen experimental runs based on an orthogonal array following the Taguchi method were performed to derive objective functions to be optimized within the experimental domain.The objective functions were selected in relation to parameters of PMAG-TIG twin arc root welding back bead geometry: back bead width to root reinforcement ratio and deposited metal height.The Taguchi approach was followed by grey relational analysis to solve the multi-response optimization problem.The significance of factors on overall quality characteristics of the weld joint was also evaluated quantitatively using analysis of variance.Optimal results were verified through additional experiments,and showed to feasibility of applying grey relation analysis in combination with Taguchi technique for continuous improvement of product quality in the manufacturing industry.     

田口设计优化的铝合金旋转叶轮除气技术

利用田口实验优化法配合水模拟实验法设计了铝合金旋转叶轮除气技术.选用L9田口正交表分析旋转叶轮除气技术的3个控制因子,包括转速、气体流量及叶轮设计.研究结果显示,使用水模拟实验法配合田口实验法,可有效的减少设计优化旋转叶轮除气技术的实验数.通过田口实验法,得出旋转叶轮除气技术的最佳参数组合,其中最重要的控制因子为转头的叶轮数目、转速和气体流量,最佳参数分别为6个叶轮片、转速500 rpm及除气气体流量2L/min.     

Employing the Taguchi method in optimizing the scaffold production process for artificial bone grafts

The Taguchi method of experimental design is very well suited to improving the production process of synthetic bone grafts for several reasons. Firstly, the effect of many different process variables can be examined simultaneously, which ensures that beneficial factor combinations are not overlooked. Secondly, it is very efficient and easy to apply, so that it does not require large amounts of time or resources to conduct a given set of experiments. This makes it possible to conduct a series of experiments that result in continuous process improvement. Finally, using a Taguchi signal-to-noise ratio permits the concurrent optimization of the process and the reduction of process variability. The ease of use, efficiency, and focus on decreasing variability while optimizing the response more than outweigh the disadvantage of the Taguchi method of experimental design, as compared with the many other experimental approaches currently in use.The current application of the Taguchi method was successful in optimizing the mechanical properties of the Si-mHA synthetic bone grafts. The compression strength was doubled while maintaining the appropriate porosity level and microstructure for bioactivity. The mean value of the compression strength obtained was 5.8 MPa with a density of 0.515 gm/cm³. Three levels of porosity were identified namely, macro-, meso-, and micro-porosity. The mean values of pore sizes were 400, 100 and 6 μm, respectively. By using the Taguchi method in conjunction with a statistical experimental design, the various steps of the scaffold production process such as slurry preparation, coating process, drying, calcining and sintering processes were optimized. The final optimized process gave highly reproducible results. The manner in which the Taguchi method was used to produce synthetic bone scaffolds with desired properties is described.     

AZ80镁合金挤压铸造工艺参数的形态学矩阵优化(英文)

运用形态学矩阵对AZ80镁合金挤压铸造工艺参数进行优化。采用 L9(33)田口方法中的正交列对不同挤压压力、模具预热温度和压力持续时间进行组合。采用一个3水平正交阵列确定信噪比,通过方差分析确定影响力学性能最重要的工艺参数,并利用多变量线性回归分析确定拉伸强度、伸长率和硬度,获得了最佳的挤压铸造工艺参数。     

基于正交试验的气辅成型工艺优化

以加强筋为研究对象,对气辅成型中的熔体温度、熔体预注射量、气体注射压力、气体注射延迟时间、气体注射时间等影响气辅成型质量的主要参数进行数值模拟,并对影响塑件成型质量的相关工艺参数进行正交试验。先通过初步的五因素四水平L16(45)正交试验获得工艺参数的大致范围,然后在该基础上再进行改进的四因素三水平L9(34)正交试验,最终获得较好的工艺条件。     

Time-modulated CVD process optimized using the taguchi method

The Taguchi method is used herein to optimize the time-modulated chemical vapor deposition (TMCVD) process. TMCVD can be used to deposit smooth, nanocrystalline diamond (NCD) coatings onto a range of substrate materials. The implementation of the Taguchi method to optimize the TMCVD process can save time, effort, and money. The Taguchi method significantly reduces the number of experiments required to optimize a fabrication process. In this study, the effect of five TMCVD process parameters is investigated with respect to five key factors of the as-grown samples. Each parameter was varied at four different values (experimental levels). The five key factors, taking into consideration the experimental levels, were optimized after performing only 16 experiments. The as-grown films were characterized for hardness, quality, surface roughness, and microstructure using scanning electron microscopy, Raman spectroscopy, surface profilometry, and Vickers hardness testing. This paper was presented at the fourth International Surface Engineering Congress and Exposition held August 1–3, 2005 in St. Paul, MN.     

合模机构移模行程的Taguchi稳健设计

为保证某企业注塑机合模机构的使用性能的稳健性,提出一种将Taguchi稳健设计理论和虚拟样机技术相结合的稳健设计求解方式。详细介绍了Taguchi三次设计方法的原理和步骤;应用ADAMS建立该合模机构的参数化模型;在参数化模型基础上,通过参数设计、容差设计先后得到了最佳参数组合和噪声因素下的最佳组合。优化结果表明:该方法提高了合模过程中开合模位置的重复精度。     

模糊田口法在重切削制程中切削参数最佳化设计

为了快速有效获得重切削时良好的切削性能参数,以田口法与模糊逻辑相结合,对侧面铣削SUS304不锈钢重切削制程时的切削参数进行最佳化设计。由于评估重切削制程的刀具寿命与金属移除率两项主要切削性能,受到主轴转速、每刃进给、轴向切深与径向切深的影响,由此将4个切削参数设置为可控制因子。经过田口法将各品质特性转化为S/N比,通过模糊逻辑运算,采用多重品质特性指标(MPCI)求得切削参数最佳水准组合。试验结果表明:以模糊田口法获得的切削参数最佳水准组合,能够有效改善侧面重切削制程时的切削性能,为刀具制造厂或刀具使用者寻求最佳切削条件提供参考。     

Parameter Optimisation of a Vacuum Plasma Spraying Process Using Boron Carbide

This study determines the optimal processing parameters for vacuum plasma spraying boron carbide (B₄C), employing an integrated approach based on the Taguchi design method, a neural network, and a genetic algorithm (GA). The proposed method comprises two stages. In the first stage, the Taguchi design method is used to establish a preliminary solution for the optimal set of processing parameters. In the second stage, the experimental results acquired from the Taguchi trials are used to construct a neural network model of the spraying process. A GA is then used to establish the optimal combination of processing parameters. The experimental results show that the coating void content of the specimen prepared using the processing parameters identified by the GA is significantly lower than that of the specimen prepared using the processing parameters identified by the Taguchi method alone.     

Multi-response optimization in friction properties of PBT composites using Taguchi method and principle component analysis

This paper optimizes the injection-molding process for friction properties of fiber-reinforced polybutylene terephthalate using Taguchi method and principal component analysis. Four controllable factors of the manufacturing process were studied at three levels each. The single-response optimization of friction property was conducted by Taguchi method. Principal component analysis was employed to correspond to multi-response cases, for transforming the correlated friction properties to a set of uncorrelated components and evaluating the principal components. The optimum combination of process factors and levels for multiple qualities, based on the first principal component, was determined first. The appropriate number of the principle components, and the influence of the number on the optimum process condition, were subsequently studied by extracting more than one principal component and integrating into a comprehensive index. Finally, the analysis of variance was used to find out the most influential injection-molding parameter for single and multiple responses problems.