混粉电火花加工工艺实验

研究采用混粉工作液的电火花加工原理,提出了适合于混粉加工的工艺参数,通过电火花加工实验,降低了加工零件的表面粗糙度值。     

大面积混粉电火花加工机理探讨

论述了大面积混粉电火花加工的机理，分析了大面积混粉电火花加工能提高加工表面粗糙度的原因，指出放电蚀坑大儿浅，并且在加工表面分布均匀是大面积混粉电火花加工提高加工表面粗糙度的根本原因，通过在普通和混粉工作液中的大面积电火花加工实验对比，证明以上结论的正确性。     

国产电火花机床混粉加工试验研究

介绍利用国产普通电火花机床进行混粉电火花加工的试验研究。结果表明 ,混粉电火花加工不但能显著改善加工表面粗糙度 ,而且能显著提高加工效率     

混粉电火花加工在模具制造中的应用

通过对混粉电火花加工工艺与传统模具制造工艺的比较，从混粉电火花加工工艺的机理、表面特性、影响因素等各方面来阐述，混粉电火花加工是生产高精度、高寿命、效率的模具的最有效的工艺之一。     

高熔点材料混粉电火花加工技术的研究

利用自行研制的混粉电火花加工装置,对高强度、高熔点的特殊材料的加工进行研究,通过优化工艺参数,成功地在直径为φ50 mm的圆面积上使加工表面粗糙度值达到Rα0.174μm.经过与常规电火花加工实验的对比,对两种方法加工工件的表面性能进行检测与分析,结果表明混粉电火花对此类材料的加工比常规电火花加工更具明显优势.     

混粉电火花加工技术

材料科学的发展和技术进步，不断提供给我们具有高熔点、高硬度、高强度、高韧性等性能的新材料，同时也向我们提出了复杂特殊的工艺要求。电火花加工技术正是为了适应生产发展的这些需要而诞生。由于加工时工具电极与工件之间不接触，而是利用两极间脉冲放电时产生的电腐蚀现象对材     

混粉电火花加工表面粗糙度的经验公式

分析了混粉电火花加工的原理,建立了混粉电火花加工回归方程数学模型,在综合考虑各种因素的基础上,推出混粉电火花加工表面粗糙度经验公式,这对混粉电火花加工的实验研究和理论研究有指导意义。     

混粉大面积电火花加工机理的分析

根据电火花加工原理和特点,分析了传统大面积电火花加工很难获得良好粗糙度的原因,同时探讨了混粉电火花加工改善大面积加工表面粗糙度的原因,并用实践验证了混粉电火花加工能改善加工表面粗糙度     

混气与混粉电火花加工机理的分析

分别介绍了混粉电火花加工和混气电火花加工的特点，以及关于混粉和混气电火花加工的机理解释，对这两种加工方法的机理进行了分析比较，从而得出两种加工方法侧重点不同的结论，即同普通电火花加工相比，混粉电火花加工易于降低表面粗糙度，而混气电火花加工速度相对较快。     

混粉电火花加工应用技术探讨

混粉电火花加工是在加工面积较大时为提高工件表面质量而在工作液中混入微粉的先进工艺方法,近几年混粉电火花在型腔模加工中发挥着越来越重要的作用。通过对该工艺的探讨,解析其使用要求及对表面质量改善状况,对企业吸收与利用当前先进的混粉电火花加工工艺提供一点帮助。     

电火花加工内齿轮

介绍电火花加工内齿轮及其工艺,并对其中的技术难题和关键技术进行了分析.用此方法加工成本低,效率高,操作方便,产品质量稳定.     

Tool-path planning for rough machining of a cavity by layer-shape analysis

In the manufacture of parts with sculptured cavities from prismatic stock, rough machining usually constitutes most of the machining time owing to the significant difference between the stock and the part shape. When using 2 1/2-D milling or a contour-map approach to do the rough machining, the appropriate selection of tool-path pattern for each cutting layer can significantly reduce rough machining time and hence increase productivity. In this paper, the commonly used toolpath patterns are summarised. A knowledge-based parametric approach for optimising the toolpath pattern of a given cutting layer is proposed. Then, a novel methodology is developed to calculate an arbitrary polygon area and locate the concave cavities in the polygon. Procedures for cutting-layer-shape analysis and the optimal comprehensive tool-path pattern generation are also built and proposed in this paper. These procedures can not only be applied to sculptured cavity parts with simple islands, but also to parts with arbitrarily-shaped islands. Finally, an example is given to illustrate the reasoning process.     

Finishing performance of die-sinking EDM with ultrasonic vibration and powder addition through pulse train studies

Abstract

Die-sinking electrical discharge machining (EDM) is widely used in die and mold-making industry. Finish EDM conditions are often selected to produce good quality surfaces. Attempts to enhance the finishing capabilities using ultrasonic vibration and powder-added dielectric medium have been reported in the literature. However, the changes in the gap phenomena with ultrasonic assistance and powder addition have not been analyzed. In this article, finish EDM of hardened D3 steel has been carried out based on full factorial design of experiment with three levels of setting voltage, setting current and pulse on time. The performance of ultrasonic assisted and graphite powder-added EDM are evaluated by analyzing the voltage and current pulse trains in finishing operation for the first time. Based on two new parameters, namely energy expended over a second (E) and ratio of energy due to sparks in relation to total discharge energy (PF), the results are discussed and also compared with those obtained with conventional EDM for selected conditions. Even though E of 102.9 J (PF?=?0.862) with ultrasonic vibration is higher than E of 43.0 J (PF?=?1.0) with powder mix, the molten metal is removed effectively from the gap by ultrasonic vibration which results in a relatively better surface. The micrographs of cross-section and surface of the workpieces obtained using optical and scanning electron microscopes, respectively, also reveal their relative performance.     

超声振动搅拌装置用于EDM加工的试验研究

利用超声波清洗原理及搅拌作用 ,设计电火花加工超声振动搅拌装置 ,并进行加工试验。结果表明 ,超声振动搅拌装置对改善加工表面粗糙度、提高加工效率有明显效果     

Effect of the powder concentration and dielectric flow in the surface morphology in electrical discharge machining with powder-mixed dielectric (PMD-EDM)

The addition of powder particles to the electrical discharge machining (EDM) dielectric fluid modifies some process variables and creates the conditions to achieve a higher surface quality in large machined areas. This paper presents a new research work that aims to study the improvement in the polishing performance of conventional EDM when used with a powder-mixed-dielectric (PMD-EDM). The analysis was carried out varying the silicon powder concentration and the flushing flow rate over a set of different processing areas and the effects in the final surface were evaluated. The evaluation was done by surface morphologic analysis and measured through some quality surface indicators. The results show the positive influence of the silicon powder in the reduction of crater dimensions, white-layer thickness and surface roughness. Moreover, it was demonstrated that an accurate control of the powder concentration and flushing flow is a requirement for achieving an improvement in the process polishing capability.     

Modeling and analysis of the effects of machining parameters on the performance characteristics in the EDM process of Al2O3+TiC mixed ceramic

Electric discharge machining (EDM) has achieved remarkable success in the manufacture of conductive ceramic materials for the modern metal industry. Mathematical models are proposed for the modeling and analysis of the effects of machining parameters on the performance characteristics in the EDM process of Al₂O₃+TiC mixed ceramic which are developed using the response surface methodology (RSM) to explain the influences of four machining parameters (the discharge current, pulse on time, duty factor and open discharge voltage) on the performance characteristics of the material removal rate (MRR), electrode wear ratio (EWR), and surface roughness (SR). The experiment plan adopts the centered central composite design (CCD). The separable influence of individual machining parameters and the interaction between these parameters are also investigated by using analysis of variance (ANOVA). This study highlights the development of mathematical models for investigating the influences of machining parameters on performance characteristics and the proposed mathematical models in this study have proven to fit and predict values of performance characteristics close to those readings recorded experimentally with a 95% confidence interval. Results show that the main two significant factors on the value of the material removal rate (MRR) are the discharge current and the duty factor. The discharge current and the pulse on time also have statistical significance on both the value of the electrode wear ratio (EWR) and the surface roughness (SR).     

State of the art in powder mixed dielectric for EDM applications

Electrical discharge machining (EDM) is a non-conventional machining technique for removing material based on the thermal impact of a series of repetitive sparks occurring between the tool and workpiece in the presence of dielectric fluid. Since the machining characteristics are highly dependent on the dielectric’s performance, significant attention has been directed to modifying the hydrocarbon oil properties or introducing alternative dielectrics to achieve higher productivity. This article provides a review of dielectric modifications through adding powder to dielectric. Utilizing powder mixed dielectric in the process is called powder mixed EDM (PMEDM). In order to select an appropriate host dielectric for enhancing machining characteristics by adding powder, a brief background is initially provided on the performance of pure dielectrics and their selection criteria for PMEDM application follow by powder mixed dielectric thoroughly review. Research shows that PMEDM facilitates producing parts with predominantly high surface quality. Additionally, some studies indicate that appropriate powder selection increases machining efficiency in terms of material removal rate. Therefore, the role of powder addition in the discharge characteristics and its influence on machining output parameters are explained in detail. Furthermore, by considering the influence of the main thermo-physical properties and concentration of powder particles, the performance of various powder materials is discussed extensively. Since suitable powder selection depends on many factors, such as variations in EDM, machining scale and electrical and non-electrical parameter settings, a thorough comparative review of powder materials is presented to facilitate a deeper insight into powder selection parameters for future studies. Finally, PMEDM research trends, findings, gaps and industrialization difficulties are discussed extensively.     

Grooved surface texturing by electrical discharge machining (EDM) under different lubrication regimes

The aim of the present research work was to investigate the effectiveness of grooved surface texturing with a rhombic geometry under different lubrication regimes. Tribological investigation under unidirectional sliding was focused on the effect of texturing parameters including pattern area density on the coefficient of friction under different lubrication regimes, achieved by varying sliding speed and lubricant viscosity. Grooved patterns with different textured area densities were produced on steel samples by electrical discharge machining. Results of this investigation showed that under boundary lubrication, textures resist sliding thus resulting in increased friction. The largest improvement of friction reduction was observed under hydrodynamic lubrication, for low‐viscosity oil when using the textured disc with 21% pattern area density. The reduction of the coefficient of friction if compared with the untextured surface was of approximately 24%. Examination of the sliding surfaces has not shown any quantifiable wear for the contact conditions studied.     

基于智能技术的电火花加工过程建模和参数优化

根据电火花加工工艺特点 ,建立基于遗传算法的加工过程人工神经网络模型 ,实现加工结果的预测。根据预测结果 ,在保证表面粗糙度要求的前提下 ,以最大加工速度为目标 ,用遗传算法实现加工参数的优化。实验结果表明以上算法可有效解决电火花加工条件优化的问题 ,自动生成加工参数 ,而且收敛速度较快 ,满足机床控制的要求。