Investigation of recast layers generated by a powder-mixed dielectric micro electrical discharge machining process

Author(s):  
P C Tan ◽  
S H Yeo
Author(s):  
Gurpreet Singh ◽  
DR Prajapati ◽  
PS Satsangi

The micro-electrical discharge machining process is hindered by low material removal rate and low surface quality, which bound its capability. The assistance of ultrasonic vibration and magnetic pulling force in micro-electrical discharge machining helps to overcome this limitation and increase the stability of the machining process. In the present research, an attempt has been made on Taguchi based GRA optimization for µEDM assisted with ultrasonic vibration and magnetic pulling force while µEDM of SKD-5 die steel with the tubular copper electrode. The process parameters such as ultrasonic vibration, magnetic pulling force, tool rotation, energy and feed rate have been chosen as process variables. Material removal rate and taper of the feature have been selected as response measures. From the experimental study, it has been found that response output measures have been significantly improved by 18% as compared to non assisted µEDM. The best optimal combination of input parameters for improved performance measures were recorded as machining with ultrasonic vibration (U1), 0.25 kgf of magnetic pulling force (M1), 600 rpm of tool rotation (R2), 3.38 mJ of energy (E3) and 1.5 mm/min of Tool feed rate (F3). The confirmation trail was also carried out for the validation of the results attained by Grey Relational Analysis and confirmed that there is a substantial improvement with both assistance applied simultaneously.


Author(s):  
Sagil James ◽  
Sharadkumar Kakadiya

Shape Memory Alloys are smart materials that tend to remember and return to its original shape when subjected to deformation. These materials find numerous applications in robotics, automotive and biomedical industries. Micromachining of SMAs is often a considerable challenge using conventional machining processes. Micro-Electrical Discharge Machining is a combination of thermal and electrical processes, which can machine any electrically conductive material at micron scale independent of its hardness. It employs dielectric medium such as hydrocarbon oils, deionized water, and kerosene. Using liquid dielectrics has adverse effects on the machined surface causing cracking, white layer deposition, and irregular surface finish. These limitations can be minimized by using a dry dielectric medium such as air or nitrogen gas. This research involves the experimental study of micromachining of Shape Memory Alloys using dry Micro-Electrical Discharge Machining process. The study considers the effect of critical process parameters including discharge voltage and discharge current on the material removal rate and the tool wear rate. A comparison study is performed between the Micro-Electrical Discharge Machining process with using the liquid as well as air as the dielectric medium. In this study, microcavities are successfully machined on shape memory alloys using dry Micro-Electrical Discharge Machining process. The study found that the dry Micro-Electrical Discharge Machining produces a comparatively better surface finish, has lower tool wear and lesser material removal rate compared to the process using the liquid as the dielectric medium. The results of this research could extend the industrial applications of Micro Electrical Discharge Machining processes.


2012 ◽  
Vol 622-623 ◽  
pp. 590-594 ◽  
Author(s):  
P. Sivaprakasam ◽  
P. Hariharen ◽  
S. Kathikheyen ◽  
S. Balusamy

Micro Electrical discharge machining (µEDM) is an electro thermal process, the cutting force is negligibly small and material removal occurs irrespective of hardness of work piece material .Micro electrical discharge machining process is capable of machining of complex shape, which is difficult to machine in conventional machining process. Last decade, the EDM process involved demand for machining requirements with short period. Since the major risk of wire breakage, deflections of electrodes were affecting the performance accuracy of EDM operation. This paper describe about a comprehensive review of micro electro discharge machining process and its process optimization techniques used for last 10 years. Micro electro discharge machining has more important given to difficult to machine materials. In order to improve the surface integrity and performance of process, need to select proper process parameters. It reports on the Micro EDM research involving the optimization of the process parameters surveying the influence of the various factors affecting the machining performance and productivity.


2019 ◽  
Vol 12 (1) ◽  
pp. 22
Author(s):  
Christina Apostolopoulou ◽  
Laith Abdullah Al-Juboori

The micro-Electrical Discharge Machining (micro-EDM) is a non-conventional machining process which utilizes electro-thermal, non-contact effects to remove material from the workpiece. Micro-EDM is controlled by many machining parameters and its accuracy is evaluated by performance measures. It is employed when high accuracy and precision are required, especially when difficult-to-machine materials, like titanium alloy Ti6Al4V, are involved. Given the tremendous applications of Ti6Al4V in biomedical devices, automotive, aerospace and microelectromechanical systems, it is valuable to examine thoroughly the micro-EDM of Ti6Al4V component. This work reports a systematic mapping study of 36 papers published in journals and proceedings of conferences in the nearly two decades 2000-2018. First, we divide the papers into categories according to the various optimization techniques applied for the enhancement of micro-EDM machining process of Ti6Al4V component. Then, we discuss the techniques most used and give insight into the current research trends in micro-EDM. Accompanying comments about the use of the mentioned studies for teaching purposes may be of considerable interest for educators.


Author(s):  
Peter A. Arrabiyeh ◽  
Maximilian Dethloff ◽  
Christopher Müller ◽  
Benjamin Kirsch ◽  
Jan C. Aurich

Micropencil grinding tools (MPGTs) are micromachining tools that use superabrasives like diamond and cubic boron nitride (cBN) grits to manufacture complex microstructures in a broad range of hard and brittle materials. MPGTs suffer from a rather low tool life, when compared to other more established microprocessing methods. It was documented that when used on hardened steel workpieces, MPGTs suffer from a large amount of adhesions, mostly located at the pivot point of the tool. These adhesions lead to the clogging of the abrasive layer and ultimately in tool failure. Another problem this machining process suffers from is the formation of substructures (smaller channels inside the microchannels). The pivot is usually less prone to abrasive wear, has higher protrusion, and is therefore responsible for the deepest substructures. These substructures can easily take up half the depth of cut, obstructing the function of machined microchannels—it is one of the major flaws of this micromachining process. A micro-electrical discharge machining method (μEDM) can solve these issues by manufacturing a cavity at the pivot of these tools. A novel method that uses measurement probes to position the substrate above the μEDM electrode is implemented and a parameter study to determine the cavity manufacturing parameters is conducted for substrates with diameters < 40 μm. The goal is to demonstrate the first ever complete and reliable manufacturing process for MPGTs with a cavity and to demonstrate the advantages they provide in a machining process when compared to regular MPGTs.


2009 ◽  
Vol 626-627 ◽  
pp. 279-284 ◽  
Author(s):  
Zi Long Peng ◽  
Zhen Long Wang ◽  
Yu Kui Wang ◽  
Ying Huai Dong ◽  
H. Chen

A reversible machining method using micro electrical discharge machining (EDM) was developed. This new method can achieve depositing or selective removing of metal material for the fabrication of micro structures. It is easy to transform the machining process from deposition to removal in one EDM machining system. In micro EDM deposition process, brass, tungsten and steel material can be deposited successfully. The deposited material has compact fine texture and combines close to workpiece. Then, micro complex structures by series deposition strategy and sub-deposition strategy were deposited. In the selective removal process, the machining effects of different working mediums were researched. Results show that the machining effect in liquid medium is better than that of in air. Finally, using the micro reversible EDM process, a micro square column with 0.070mm in side length, 0.750mm in height and a micro cylinder with 0.140mm in diameter, 1.180mm in height were fabricated.


2009 ◽  
Vol 626-627 ◽  
pp. 267-272 ◽  
Author(s):  
Jin Wang ◽  
Yuan Gang Wang ◽  
Fu Ling Zhao

In micro electrical discharge machining (micro-EDM) of deep holes, the debris dispersed in gap may increase the possibility of secondary discharge, resulting in electrode shape changing and low accuracy of machined hole. In this paper, the debris movement caused by flow fluid in the machining gap is analyzed to understand the mechanism of debris transport by using software, FLUENT. Comparison of debris movement calculated by the modified N-S equation and N-S equation is conducted. Debris movement calculated by the modified N-S equation is demonstrated to be correct by experiment. The simulation results can explain the phenomena such as subulate electrode and hole, unstable machining process and low machining speed in micro-EDM of deep holes. It is helpful to improve the process of micro-EDM.


2009 ◽  
Vol 69-70 ◽  
pp. 177-181
Author(s):  
Zi Long Peng ◽  
Zhen Long Wang ◽  
Ying Huai Dong ◽  
Hui Chen

Based on the principle of micro electrical discharge machining (EDM), a reversible machining method is proposed, which can achieve depositing or removing selectively metal material for the fabrication of micro structures. It is easy to transform the machining process from deposition to removal in one machining system. The characteristics of the deposited material show that the components of deposited material are almost the same as those of the tool electrode, and the metallurgical bonding has formed on the interface between the deposited material and the base. Moreover, the deposited material has well machinability in different micro EDM selective removal process, including micro EDM die-sinking and micro EDM milling. As a result, a micro square column with 0.1mm in side length, 0.88mm in height and a micro cylinder with 0.14mm in diameter, 1.18mm in height were fabricated by using the micro reversible EDM process.


2020 ◽  
Vol 13 (3) ◽  
pp. 219-229
Author(s):  
Baocheng Xie ◽  
Jianguo Liu ◽  
Yongqiu Chen

Background: Micro-Electrical Discharge Machining (EDM) milling is widely used in the processing of complex cavities and micro-three-dimensional structures, which is a more effective processing method for micro-precision parts. Thus, more attention has been paid on the micro-EDM milling. Objective : To meet the increasing requirement of machining quality and machining efficiency of micro- EDM milling, the processing devices and processing methods of micro-EDM milling are being improved continuously. Methods: This paper reviews various current representative patents related to the processing devices and processing methods of micro-EDM milling. Results: Through summarizing a large number of patents about processing devices and processing methods of micro-EDM milling, the main problems of current development, such as the strategy of electrode wear compensation and the development trends of processing devices and processing methods of micro-EDM milling are discussed. Conclusion: The optimization of processing devices and processing methods of micro-EDM milling are conducive to solving the problems of processing efficiency and quality. More relevant patents will be invented in the future.


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