Grinding-aided electrochemical discharge drilling in the light of electrochemistry

Author(s):  
VG Ladeesh ◽  
R Manu

The electrically non-conductive materials like glass, ceramics, quartz, etc. are of great interest for many applications in modern industries. Machining them with high quality and at a faster rate is a challenging task. In this study, a novel technique called grinding aided electrochemical discharge drilling (G-ECDD) is demonstrated which uses a hollow diamond core drill as the tool for performing electrochemical discharge machining of borosilicate glass. The new hybrid technique enhances the material removal rate and machining accuracy to several folds by combining the thermal melting action of discharges and grinding action of the abrasive tool. This paper presents the experimental investigation on the material removal rate during G-ECDD of glass while using different electrolytes. An attempt has been made to explore the influence of electrolyte temperature on G-ECDD performance by maintaining the electrolyte at different temperatures. Experiments were conducted using three different electrolytes which include NaOH, KOH, and the mixture of both. The results obtained from this study revealed that an increase in temperature will favor chemical etching as well as electrochemical reaction rate. Also, it was observed that heating the electrolyte leads to an increase in the bubble density and enhances the ion mobility. This causes the formation of gas film at a faster rate and thereby improving the discharge activity. Thus, machining will be done at a faster rate. Better results are obtained while using a mixture of NaOH and KOH. From the microscopic images of the machined surface, it was observed that material removal mechanism in G-ECDD is a combination of grinding action, electrochemical discharges, and chemical etching. Response surface methodology was adopted for studying the influence of process parameters on the performance of G-ECDD. The new technique of grinding aided electrochemical discharge drilling proved its potential to machine borosilicate glass and simultaneously offers good material removal rate, repeatability, and accuracy.

Author(s):  
Hariharan Perianna Pillai ◽  
Shamli Chinnakulanthai Sampath ◽  
Rajkeerthi Elumalai ◽  
Shruthilaya Hariharan ◽  
Yuvaraj Natarajan

Electrochemical micromachining process is one among the successful micromachining technique, which uses the electrochemical energy and is recognized for machining difficult-to-cut materials. One such material is Nimonic 75 alloy, which is used to make gas turbine components. In this study, an effort has been made to machine micro-hole profiles in Nimonic 75 with a thickness of 500 μm using two different electrolytes. A combination of sodium bromide, hydrofluoric acid and ethylene glycol has been chosen as the first electrolyte, while the second is a combination of sodium chloride and sodium nitrate. Solid tungsten carbide of diameter 500 μm is used as the tool in each case. For layout of experiments, Taguchi orthogonal array was chosen with following input parameters namely voltage, micro-tool feed rate and duty cycle. Performance characteristics such as material removal rate, overcut and conicity have been assessed for each electrolyte. Experimental results have shown that the first electrolyte yields lower values of overcut (OC) and conicity, whereas the second electrolyte gives higher material removal rate (MRR). Further, the optimal combinations of process parameters have been found by implementing the TOPSIS procedure and the results were found to be in good agreement with the experimental outcomes.


Materials ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 125 ◽  
Author(s):  
Lei Guo ◽  
Xinrong Zhang ◽  
Shibin Chen ◽  
Jizhuang Hui

Ultraviolet-curable resin was introduced as a bonding agent into the fabrication process of precision abrasive machining tools in this study, aiming to deliver a rapid, flexible, economical, and environment-friendly additive manufacturing process to replace the hot press and sintering process with thermal-curable resin. A laboratory manufacturing process was established to develop an ultraviolet-curable resin bond diamond lapping plate, the machining performance of which on the ceramic workpiece was examined through a series of comparative experiments with slurry-based iron plate lapping. The machined surface roughness and weight loss of the workpieces were periodically recorded to evaluate the surface finish quality and the material removal rate. The promising results in terms of a 12% improvement in surface roughness and 25% reduction in material removal rate were obtained from the ultraviolet-curable resin plate-involved lapping process. A summarized hypothesis was drawn to describe the dynamically-balanced state of the hybrid precision abrasive machining process integrated both the two-body and three-body abrasion mode.


2010 ◽  
Vol 42 ◽  
pp. 170-174
Author(s):  
Cheng Guang Zhang ◽  
Xue Ling Yang ◽  
Bo Zhao

The experiment of ultrasonic assisted pulse electrochemical compound finishing is carried in this paper. The machining principle of the compound finishing is discussed in this paper. Processing experiments of compound finishing are carried out to study the effects of the main processing para- meters, including the particle size, the ultrasonic vibration amplitude, the minimum gap between the tool head and workpiece and the pulse voltage, on the material removal rate and the surface quality for hard and brittle metal materials. The curves of the corresponding relationships are also obtained. The study indicates that the processing velocity, machining accuracy and surface quality can be improved under the compound finishing, obtaining the processing technology conductions of the compound finishing. Introductions


2021 ◽  
Vol 49 (3) ◽  
pp. 756-763
Author(s):  
Kapil Gupta

This work presents the wire-EDM of WC-Co composite and optimization of process parameters using an integrated technique of response surface methodology (RSM), Vise Kriterijumska Optimizacija Kompromisno Resenje (VIKOR) and artificial bee colony (ABC) algorithm to obtain the best set of machinability indicators. Wire feed (WF), servo voltage (SV), pulse off-time (Pon) and pulse on-time (Poff) are the variable process parameters, whereas root mean square roughness (Rq), average surface roughness (Ra) and material removal rate (MRR) are the machinability indicators considered in the present work. A total of twenty nine experiments have been conducted based on Box Behnken design (BBD) technique of response surface methodology. VIKOR has been used for normalization of responses and followed by solving empirical models using ABC algorithm to obtain optimized process parameters setting. WF-12 m/min, SV-65V, Pon-116 µs, Poff-20 µs are the optimum wire-EDM parameters obtained by intelligent RSM-VIKOR-ABC technique that produced best values of Ra-4.51 µm, Rq-5.64 µm, MRR-0.061 mm3 /min simultaneously. The validation test confirmed an improvement up to 15% in the response characteristics which proved the effectiveness of this novel hybrid technique for optimization. The optimum parameter setting is for ready industrial reference to attain best surface quality and process productivity for WC-Co composite machining by wire-EDM.


Author(s):  
R Rajeswari ◽  
MS Shunmugam

Electrical discharge machining is used in the machining of complicated shapes in hardened molds and dies. In rough die-sinking stage, attempts are made to enhance material removal rate with a consequential reduction in cycle time. Powder mix and ultrasonic assistance are employed in the electrical discharge machining process to create gap conditions favoring material removal. In the present work, experiments are carried out on hardened D3 die steel using full-factorial design based on three levels of voltage, current and pulse on time. The gap phenomena in graphite powder-mixed and ultrasonic-assisted rough electrical discharge machining are studied using a detailed analysis of pulse shapes and their characteristic trains. Two new parameters, namely, energy expended over a second ( E) and performance factor ( PF) denoting the ratio of energy associated with sparks to total discharge energy, bring out gap conditions effectively. In comparison with the conventional electrical discharge machining for the selected condition, it is seen that the graphite powder mixed in the dielectric enhances the material removal rate by 20.8% with E of 215 J and PF of 0.227, while these values are 179.8 J and 0.076 for ultrasonic-assisted electrical discharge machining with marginal reduction of 3.9%. Cross-sectional images of workpieces also reveal the influence of electrical discharge machining conditions on the machined surface. The proposed approach can be extended to different powder mix and ultrasonic conditions to identify condition favoring higher material removal.


2014 ◽  
Vol 1030-1032 ◽  
pp. 1305-1308
Author(s):  
Shi Chao Li ◽  
Song Lin Wu ◽  
Yan Kun Liang

It is a general processing technology that multi-axis NC machine tools is used for machining impeller at present. In order to improve the machining accuracy of the five-axis NC machine tools, the paper analyzes the computing interpolation error of the Multi-axis CNC system in detail. Some of the measures of tools selection have been proposed in purpose of diminishing the accumulative error of the system. The paper also establishes the optimized objective function to optimize the process parameters of the CNC machining based on the material removal rate. All these measures will improve the machining efficiency significantly and increase the stationary of the machining process.


2012 ◽  
Vol 523-524 ◽  
pp. 155-160 ◽  
Author(s):  
Ya Guo Li ◽  
Yong Bo Wu ◽  
Li Bo Zhou ◽  
Hui Ru Guo ◽  
Jian Guo Cao ◽  
...  

Ultrasonic vibration assisted processing is well known for the improvement in machined surface quality and processing efficiency due to the reduced forces and tribology-generated heating when grinding hard-brittle materials. We transplanted this philosophy to chemo-mechanical fixed abrasive polishing of optical glass, namely fused silica, in an attempt to improve surface roughness and/or material removal rate. Experiments were conducted to elucidate the fundamental characteristics of chemo-mechanical fixed abrasive polishing of fused silica in the presence and absence of ultrasonic vibration on a setup with an in-house built gadget. The experimental results show that ultrasonic vibration assisted chemo-mechanical fixed abrasive polishing can yield increased material removal rate while maintaining the surface roughness of manufactured optics compared to conventional fixed abrasive polishing without ultrasonic vibration. The mechanism of material removal in fixed abrasive polishing was also delved. We found that the glass material is removed through the synergic effects of chemical and mechanical actions between abrasives and glass and the resultant grinding swarf contains ample Si element as well as Ce element, standing in stark contrast to the polisher that contains abundant Ce element and minor Si element.


Sign in / Sign up

Export Citation Format

Share Document