Surface Integrity of Sintered NdFeB Permanent Magnet after EDM

2012 ◽  
Vol 503-504 ◽  
pp. 27-30
Author(s):  
Li Li ◽  
Zong Wei Niu ◽  
Feng Shi Yin ◽  
Yuan Yong Liu

In this study, the machining parameters of electrical discharge machining (EDM) are varied to study the effects of electrical discharge energy on material removal rate and surface roughness of NdFeB magnet. Moreover, the micro-cracks on the machined surface induced by EDM are also examined. The experimental results reveal that the MRR increases with the electrical discharge energy. The surface cracks on the machined surface are more serious when the discharge energy is higher. Thus, using EDM process to machine sintered NdFeB magnet depends on setting the machining parameters to prevent surface crack.

2009 ◽  
Vol 620-622 ◽  
pp. 711-714 ◽  
Author(s):  
Li Li ◽  
Guang Ming Yuan ◽  
Zong Wei Niu ◽  
Rong Guo Hou

Sintered NdFeB permanent magnet is widely used in many areas because of its excellent magnet property. In this study, the machining parameters of electrical discharge machining (EDM) are varied to study the effects of electrical discharge energy on material removal rate and surface roughness of NdFeB magnet. Moreover, the micro-cracks on the machined surface induced by EDM are also examined. The experimental results reveal that the MRR increases with the electrical discharge energy. The number of surface cracks on the machined surface increases with the enhancement of discharge energy Thus, using EDM process to machine sintered NdFeB magnet depends on setting the machining parameters to prevent surface crack.


2017 ◽  
Vol 14 (1) ◽  
pp. 47-64 ◽  
Author(s):  
Pouyan Sadr ◽  
Amin Kolahdooz ◽  
Seyyed Ali Eftekhari

Electrical Discharge Machining (EDM) process is one of the most widely used methods for machining. This method is used to form parts that conduct electricity. This method of machining has used for hard materials and therefore select the correct values of parameters are so effective on the quality machining of parts. D3 steel has a high abrasion resistance at low temperatures therefore can be a good candidate for this method of machining. Also because of high hardness and low distortion during heat treatment, using this method is economical for this alloy. The purpose of this paper is to investigate the influence of the main parameters such as voltage, current, pulse duration and pulse off time and the interaction of them to determine the optimal condition for the D3 steel alloy (alloy with DIN 1.2080). Chip removal rate (MRR) and surface quality of parts were evaluated as the output characteristic of the study. The optimum conditions were achieved when the MRR is in the highest value and surface roughness is in the lowest one. For investigation of interaction, two kinds of DOE methods (Taguchi and determinant of optimal experimental design) are used. Then the optimal parameters are investigated with the help of the analysis signal to noise (S/N) and mathematical modeling. The optimize results were tested again and compared. Also the results showed that regression modeling has better accuracy than the S/N analysis. This is because of a greater number of experiments that done in this part and taking into account the interaction parameters in the regression model.


2009 ◽  
Vol 407-408 ◽  
pp. 628-631
Author(s):  
Li Li ◽  
Zong Wei Niu ◽  
Guang Ming Yuan

Sintered NdFeB magnet is widely used in many areas because of its excellent magnet. This paper studies the effect of ultrasonic vibration of tool on electrical discharge machining of it. Experiments were carried out on self-made equipment and material removal rate(MRR) against pulse-on time, MRR versus peak current and machined surface results with and without ultrasonic employment were analyzed. Results show that MRR of the ultrasonic assisted electro-discharge machining would be up to five times higher than MRR of the conventional EDM for small pulse durations and low discharge currents. The machined surface of US/EDM is finer than EDM because of less arcing and short circuit pulses. There are less cracks on the surface.


2012 ◽  
Vol 488-489 ◽  
pp. 871-875
Author(s):  
V. Anandakrishnan ◽  
V. Senthilkumar

Copper based metal matrix composite reinforced with Boron Carbide is a newly developed Electrical Discharge Machining (EDM) electrode showing better performance than the conventional copper based electrode. Right selection of machining parameters such as current, pulse on time and pulse off time is one of the most important aspects in EDM. In this paper an attempt has been made to develop mathematical models for relating the Material Removal Rate (MRR), Tool Removal Rate (TRR) and Surface roughness (Ra) to machining parameters (current, pulse-on time and pulse-off time). Furthermore, a study was carried out to analyze thSubscript texte effects of machining parameters on various performance parameters such as, MRR, TRR and Ra. The results of Analysis of Variance (ANOVA) indicate that the proposed mathematical models, can adequately describe the performance within the limits of the factors being studied. Response surface modeling is used to develop surface and contour graphs to analyze the effects of EDM input parameters on outer parameters.


Manufacturing ◽  
2003 ◽  
Author(s):  
Scott F. Miller ◽  
Albert J. Shih

The development of new, advanced engineering materials and the needs for precise and flexible prototype and low-volume production have made wire electrical discharge machining (EDM) an important manufacturing process to meet such demand. This research investigates the effect of spark on-time duration and spark on-time ratio, two important EDM process parameters, on the material removal rate (MRR) and surface integrity of four types of advanced material: porous metal foams, metal bond diamond grinding wheels, sintered Nd-Fe-B magnets, and carbon-carbon bipolar plates. An experimental procedure was developed. During the wire EDM, five types of constraints on the MRR due to short circuit, wire breakage, machine slide speed limit, and spark on-time upper and lower limits have been identified. An envelope of feasible EDM process parameters is created and compared across different work-materials. Applications of such process envelope to select process parameters for maximum MRR and for machining of micro features are presented.


2015 ◽  
Vol 656-657 ◽  
pp. 335-340 ◽  
Author(s):  
Fang Pin Chuang ◽  
Yan Cherng Lin ◽  
Hsin Min Lee ◽  
Han Ming Chow ◽  
A. Cheng Wang

The environment issue and green machining technique have been induced intensive attention in recent years. It is urgently need to develop a new kind dielectric to meet the requirements for industrial applications. The aim of this study is to develop a novel dielectric using gas media immersed in deionized water for electrical discharge machining (EDM). The developed machining medium for EDM can fulfill the environmentally friendly issue and satisfy the demand of high machining performance. The experiments were conducted by this developed medium to investigate the effects of machining parameters on machining characteristics in terms of material removal rate (MRR) and surface roughness. The developed EDM medium revealed the potential to obtain a stabilizing progress with excellent machining performance and environmentally friendly feature.


Author(s):  
Anshuman Kumar Sahu ◽  
Joji Thomas ◽  
Siba Sankar Mahapatra

Electrical discharge machining (EDM) is a thermo-electrical process that can be conveniently utilized for generating complex shaped profiles on hard-to-machine conductive materials using metallic tool electrodes. In this work, composite tools made of copper-tungsten-boron carbide (Cu-W-B4C) manufactured by powder metallurgy (PM) route are used during machining of titanium alloy (Ti6Al4V). The effect of four input machining parameters viz. current, pulse-on-time, duty cycle and percentage of tungsten and boron carbide on material removal rate (MRR), tool wear rate (TWR) and surface roughness (Ra) is studied. A novel meta-heuristic approach such as simple optimization (SOPT) algorithm has been used for single and multi-objective optimization. The pareto-optimal solutions obtained by SOPT have been ranked by VIKOR method to find out the best suitable optimal solution. Analysis of experimental data suggests vital information for controlling the machining parameters to improve the machining performance.


Machines ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 12 ◽  
Author(s):  
Angelos P. Markopoulos ◽  
Emmanouil-Lazaros Papazoglou ◽  
Panagiotis Karmiris-Obratański

Although electrical discharge machining (EDM) is one of the first established non-conventional machining processes, it still finds many applications in the modern industry, due to its capability of machining any electrical conductive material in complex geometries with high dimensional accuracy. The current study presents an experimental investigation of ED machining aluminum alloy Al5052. A full-scale experimental work was carried out, with the pulse current and pulse-on time being the varying machining parameters. The polishing and etching of the perpendicular plane of the machined surfaces was followed by observations and measurements in optical microscope. The material removal rate (MRR), the surface roughness (SR), the average white layer thickness (AWLT), and the heat affected zone (HAZ) micro-hardness were calculated. Through znalysis of variance (ANOVA), conclusions were drawn about the influence of machining conditions on the EDM performances. Finally, semi empirical correlations of MRR and AWLT with the machining parameters were calculated and proposed.


2013 ◽  
Vol 675 ◽  
pp. 365-369 ◽  
Author(s):  
Yan Cherng Lin ◽  
Han Ming Chow ◽  
Hai Ping Tsui ◽  
Yuan Feng Chen

The aim of this study is to investigate the machining characteristics of ultrasonic vibration assisted electrical discharge machining (EDM) process using gas media as the dielectric fluids. The process parameters were designed based on Taguchi method to conduct the experimental works. The main process parameters such as machining polarity, peak current, pulse duration, air pressure, working time, and servo reference voltage were chosen to determine their effects on machining performance in terms of material removal rate and surface roughness for SKD 61 tool steels. The experimental response values were transferred to signal-to-noise (S/N) ratios, and then the significant machining parameters associated with the machining performance were examined by analysis of variance (ANOVA). Therefore, the technique of ultrasonic vibration assisted EDM process in gas media was established with the concerning features related to environmentally friendly, high efficiency, and high machining quality to fit the demands of modern manufacturing applications.


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