Acoustic Emission Signals in the Micro-EDM of PCD

2008 ◽  
Vol 33-37 ◽  
pp. 1181-1186 ◽  
Author(s):  
M. Mahardika ◽  
Kimiyuki Mitsui ◽  
Zahari Taha
Keyword(s):  
Acoustic Emission ◽  
Elastic Wave ◽  
Electrical Discharge ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Polycrystalline Diamond ◽  
Micro Edm ◽  
Micro Electrical Discharge Machining ◽  
Single Discharge ◽  
Ae Signals

The mechanism of fracture in micro-electrical discharge machining (-EDM) processes is related to the discharge pulses energy. This paper investigates the correlation of fractures and discharge pulses energy in the -EDM of polycrystalline diamond (PCD) to the acoustic emission (AE) signals. The evaluation of fracture mechanism was done by measuring the generation and propagation of elastic wave in single discharge pulse by using AE sensor. The results show a strong correlation between fractures and discharge pulses energy to the AE signals and mechanism of material removal in the -EDM processes.

Study on the Effect of Nano and Micro MoS2 Powder in Micro-Electrical Discharge Machining

2011 ◽  
Vol 264-265 ◽  
pp. 1450-1455 ◽  
Author(s):  
Gunawan Setia Prihandana ◽  
Tutik Sriani ◽  
Kei Prihandana ◽  
Yuta Prihandana ◽  
Muslim Mahardika ◽  
...  
Keyword(s):  
Surface Quality ◽  
Material Removal Rate ◽  
Electrical Discharge ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Micro Edm ◽  
Micro Electrical Discharge Machining ◽  
Powder Suspension ◽  
Size Powder

The application of powder mixed dielectric to improve the efficiency of electrical discharge machining (EDM) has been acknowledged extensively. However, the study of micro-size powder suspension in micro-EDM field is still limited. In this research, nano and micro size powder of MoS2 were used as catalyst agent. Powder suspension in different size was able to provide significant improvement in material removal rate and surface quality to increase the efficiency in μ- EDM processes.

Monitoring of material-removal mechanism in micro-electrical discharge machining by pulse classification and acoustic emission signals

2020 ◽  
pp. 095440542092756 ◽  
Author(s):  
Kanka Goswami ◽  
GL Samuel
Keyword(s):  
Acoustic Emission ◽  
Electrical Discharge ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Distribution Analysis ◽  
Removal Mechanism ◽  
Material Removal Mechanism ◽  
Time Frequency ◽  
Feed Forward Back Propagation ◽  
Micro Electrical Discharge Machining

Micro-electrical discharge machining is a stochastic process where the interaction between the materials and the process parameters are difficult to understand. Monitoring of the process becomes necessary to achieve the dimensional accuracy of the micro-featured components. Although thermo-mechanical erosion is the most accepted material-removal mechanism, it fails to explain the material removal with very short pulse duration. Alternative postulate like electrostatic force-induced stress yielding provides a stronger argument, rising ambiguity over the material-removal process in the micro-electrical discharge machining regime. In this work, it was found that the stress waves released from the material during micro-electrical discharge-machining process indicate material removal by mechanical deformation and fracture mechanism. These stress waves were captured using the acoustic emission sensor. The discharge pulses were captured by voltage measurement and classified using voltage gradient and machining time duration into three major categories, open pulse, normal pulse and arc pulse. The acoustic emission signal features were extracted and identified by time–frequency–energy distribution analysis. A feed-forward back-propagation neural network mapping of the pulse instances was performed with the obtained acoustic emission signature. The time–frequency–energy distribution analysis of the acoustic emission and the scanning electron microscope images of the craters provide conclusive evidence that the material is removed by mechanical stress and fracture. The feed-forward back-propagation network model was trained to predict the discharge categories of the pulse instances with AE signal inputs which can be used for monitoring the material-removal mechanism in micro-electrical discharge machining operation.

Recent Patents on Micro-EDM Milling

2020 ◽  
Vol 13 (3) ◽  
pp. 219-229
Author(s):  
Baocheng Xie ◽  
Jianguo Liu ◽  
Yongqiu Chen
Keyword(s):  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Three Dimensional ◽  
Processing Method ◽  
Electrode Wear ◽  
Micro Edm ◽  
Processing Efficiency ◽  
Processing Methods ◽  
Machining Quality ◽  
Micro Electrical Discharge Machining

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.

Optimization of μEDM process assisted with rotating magnetic pulling force and ultrasonic vibration

2021 ◽  
pp. 095440892098440
Author(s):  
Gurpreet Singh ◽  
DR Prajapati ◽  
PS Satsangi
Keyword(s):  
Ultrasonic Vibration ◽  
Material Removal Rate ◽  
Electrical Discharge ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Machining Process ◽  
Micro Electrical Discharge Machining ◽  
Pulling Force ◽  
Tool Rotation

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.

Experimental Study of Machining of Shape Memory Alloys Using Dry Micro Electrical Discharge Machining Process

2018 ◽  
Author(s):  
Sagil James ◽  
Sharadkumar Kakadiya
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Electrical Discharge ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Dielectric Medium ◽  
Machining Process ◽  
Machining Processes ◽  
Micro Electrical Discharge Machining

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.

On Correlation of Pulses and Tool Elongations at Micro-Electrical Discharge Machining Aided by Ultrasonics

2015 ◽  
Vol 809-810 ◽  
pp. 309-314
Author(s):  
Daniel Ghiculescu ◽  
Nicolae Marinescu ◽  
Tomasz Klepka ◽  
Nicoleta Carutasu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Electrical Discharge ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Removal Mechanism ◽  
Material Removal Mechanism ◽  
Micro Electrical Discharge Machining ◽  
Machining Strategy ◽  
Element Method

The paper deals with Finite Element Method (FEM) of thermal and mechanical-hydraulic components of material removal mechanism at micro-electrical discharge machining aided by ultrasonics (μEDM+US), due to EDM and US contribution. The dimensions of craters produced by single discharges under μEDM+US conditions are determined with different pulse durations in order to establish a machining strategy with correlation of pulses and tool elongations.

scholarly journals Effect of machining polarity on single discharge characteristics in micro-EDM

2020 ◽  
Vol 191 ◽  
pp. 04004
Author(s):  
Kan Wang ◽  
Yong Liu
Keyword(s):  
Energy Distribution ◽  
Electrical Discharge Machining ◽  
Micro Edm ◽  
Positive Polarity ◽  
Discharge Characteristics ◽  
Micro Electrical Discharge Machining ◽  
Crater Size ◽  
Single Discharge ◽  
Plasma Radius ◽  
The Difference

In micro electrical discharge machining (micro-EDM), polarity effect is attributed to the difference in energy distribution into the anode and cathode. Understanding the effect of machining polarity on energy distribution bears significance in predicting and controlling machining performances. Single discharge experiments were conducted in this study, to explore single discharge characteristics. The plasma radius and energy distribution were calculated by combining the crater size and the electro-thermal model. The results show that the influence of discharge current on crater depth-to-diameter ratio (H/D) is not significant with positive polarity. The plasma radius, fraction of energy transferred to workpiece, and crater size are greater for micro-EDM with negative polarity than positive polarity.

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