Modelling and simulation of ultrasonic-assisted jet electrochemical micro drilling process

Author(s):  
Harsha Goel ◽  
Usharani Rath ◽  
Pulak M Pandey

Ultrasonic-assisted jet electrochemical micro drilling is an advanced variant of electrochemical machining to drill micro holes quickly and efficiently. The present article deals with the modelling and simulation of the integration of ultrasonic vibration with the conventional jet electrochemical micro drilling process. Multi-physics-based modelling and simulation approach has been used in the present work. The flow pattern of electrolyte jet was analysed for both jet electrochemical micro drilling and ultrasonic-assisted jet electrochemical micro drilling processes. The simulation results were validated with the previous experimental findings of ultrasonic-assisted jet electrochemical micro drilling process. It was found that the material removal rate (MRR) improved significantly as the ultrasonic wave got superimposed onto the electrolyte jet. In addition to that, voltage and concentration of the electrolyte also played vital roles in improving the MRR.

Author(s):  
Harsha Goel ◽  
Pulak M Pandey

The article describes fabrication of an experimental setup which could be used for electrochemical drilling process to produce micro-holes in a copper workpiece with its different variants, namely, jet electrochemical micro-drilling, air-assisted jet electrochemical micro-drilling, ultrasonic-assisted jet electrochemical micro-drilling, and pulsed direct current–jet electrochemical micro-drilling process. Process parameters like voltage, electrolyte concentration, interelectrode gap, and electrolyte pressure have been selected to find out their effects on the process responses, namely, hole taper and material removal rate in all the above process. Attachments for air assistance and ultrasonic vibration application have been fabricated and incorporated in the setup. The effects of ultrasonic vibrations and the pulsed direct current voltage on the process responses like material removal rate and hole taper have been investigated. The effect of application of ultrasonic vibrations on the electrolyte jet has been studied. The experimental findings of ultrasonic-assisted jet electrochemical micro-drilling were compared with the findings of jet electrochemical micro-drilling. Similarly, the findings of pulsed direct current–jet electrochemical micro-drilling were also compared with the results of pulsed direct current ultrasonic-assisted jet electrochemical micro-drilling experiments. It has been found that the ultrasonic vibrations have significant effect on the two process responses. From the results, it was observed that with the use of ultrasonic vibrations, the material removal rate has increased to significant level and the hole taper has been decreased than in jet electrochemical micro-drilling. Effects of the pulsed direct current voltage supply on jet electrochemical micro-drilling and (ultrasonic-assisted jet electrochemical micro-drilling) were also analyzed. Application of pulsed direct current voltage has improved the material removal rate and reduced the hole taper in jet electrochemical micro-drilling as well as in ultrasonic-assisted jet electrochemical micro-drilling. The experimental results concluded that ultrasonic assistance have generated the holes with greater material removal rate and lower hole taper and with continuous direct current and pulsed direct current voltage.


Author(s):  
Baoyang Jiang ◽  
Shuhuai Lan ◽  
Jun Ni

Electrochemical discharge machining (ECDM) is a non-conventional micromachining technology, and is highlighted for non-conductive brittle materials. However, the outcomes of ECDM have many restrictions in application due to limitations on efficiency, accuracy, and machining quality. In this paper, a drilling incorporated ECDM process is presented and analyzed to enhance material removal rate in ECDM drilling process. Incorporating micro-drilling into ECDM significantly increases the rate of material removal, especially in deep hole drilling. As fundamentals of the machining process, material removal mechanisms have been investigated to account for the increment in material removal rate by incorporating micro-drilling. Vibration of tool electrode, induced by a piezo-actuator, was introduced to further enhance material removal rate. Quantitative studies were conducted to determine the appropriate process parameters of drilling incorporated ECDM with tool vibration.


2019 ◽  
Vol 18 (03) ◽  
pp. 413-434
Author(s):  
Harsha Goel ◽  
Pulak M. Pandey

This article presents an experimental study of a recently developed process, namely, ultrasonic assisted jet electrochemical micro-drilling (UAJet-ECMD) using pulsed DC voltage power supply. The goal of the work was to examine the effect of pulsed DC voltage on the performance of UAJet-ECMD process. In the previous work carried out by the authors, the process has been studied using the continuous DC voltage. The pulse “on” time (pulsed DC voltage), electrolyte pressure and pulse “on” time (ultrasonic vibrations) were selected as the process parameters, whereas material removal rate (MRR) and hole taper were chosen as process responses. It was found that the pulse “on” time (pulsed DC voltage) had crucial effect on the MRR as well as on the hole taper. MRR and hole taper were both found to increase with rise in pulse “on” time (pulsed DC voltage). Optimization of process responses of UAJet-ECMD process was done. The responses obtained for optimized set of process parameters were verified and found in good conformity with the experimental results.


2006 ◽  
Vol 532-533 ◽  
pp. 21-24
Author(s):  
Bao Xian Jia ◽  
Wan Sheng Zhao ◽  
Fang Sun ◽  
Zhen Long Wang

It is necessary to drill micro holes in some hard brittle materials. Comparing with electro discharge machining, electrochemical machining and laser machining, the ultrasonic machining (USM) has unique advantages in hard brittle materials machining. The aim of this paper is to present experimental work that has been done in micro holes machining by micro USM. The main machining mechanisms of USM are discussed. It is pointed out that the contributions of each mechanism to material removal rate are different in different cases. By using micro USM with workpiece vibration and tool feeding in constant rate, the experiments of micro holes machining are carried out and the process laws of tool wear are studied. Some phenomena are found and the causation of causing these phenomena is analyzed. A Ø13μm micro hole is obtained.


Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 41 ◽  
Author(s):  
Hao Zhu ◽  
Zhaoyang Zhang ◽  
Kun Xu ◽  
Jinlei Xu ◽  
Shuaijie Zhu ◽  
...  

The fabrication of micro-holes in silicon substrates that have a proper taper, higher depth-to-diameter ratio, and better surface quality has been attracting intense interest for a long time due to its importance in the semiconductor and MEMS (Micro-Electro-Mechanical System) industry. In this paper, an experimental investigation of the machining performance of the direct and chemical-assisted picosecond laser trepanning of single crystalline silicon is conducted, with a view to assess the two machining methods. The relevant parameters affecting the trepanning process are considered, employing the orthogonal experimental design scheme. It is found that the direct laser trepanning results are associated with evident thermal defects, while the chemical-assisted method is capable of machining micro-holes with negligible thermal damage. Range analysis is then carried out, and the effects of the processing parameters on the hole characteristics are amply discussed to obtain the recommended parameters. Finally, the material removal mechanisms that are involved in the two machining methods are adequately analyzed. For the chemical-assisted trepanning case, the enhanced material removal rate may be attributed to the serious mechanical effects caused by the liquid-confined plasma and cavitation bubbles, and the chemical etching effect provided by NaOH solution.


2013 ◽  
Vol 549 ◽  
pp. 503-510 ◽  
Author(s):  
Gianluca D'Urso ◽  
Giancarlo Maccarini ◽  
C. Merla

The recent miniaturization trend in manufacturing, has enhanced the production of new and highly sophisticated systems in various industrial fields. In recent years, machining of the so called difficult to cut materials has become an important issue in several sectors. Micro Electrical Discharge Machining (micro-EDM) thanks to its contactless nature, is one of the most important technologies for the machining of this type of materials and it can be considered as one of the most promising manufacturing technologies for the fabrication of micro components. One of the most relevant applications of micro-EDM is micro-drilling. Micro holes in fact, are widely used for example in micro-electromechanical systems (MEMS), serving as channels or nozzles to connect two micro-features, and in micro-mechanical components. The present study is about micro drilling of metal plates by means of micro-EDM technology. In particular, the aim of this work is to investigate the effects of the downsizing of the micro holes diameter on the drilling performances. The influence of the reduction of the diameters in terms of both process performances (e.g., tool wear, taper rate, diametrical overcut) and general quality of the holes was investigated. Steel plates having thickness equal to 0.8 mm were taken into account. The drilling process was carried out using a micro-EDM machine Sarix SX 200 with carbide electrodes having diameter equal to 300, 200, 100 and 50 μm. Since the standard electrodes adopted in this study had a diameter equal to 300 μm, a wire EDM unit was used to obtain the other electrodes. The relationship between the process parameters considered the most significant and the final output, was studied. Furthermore, the geometrical and dimensional properties of the micro-holes were analyzed using both optical and scanning electron microscopes. In particular, it is demonstrated that the diameter size has a significant influence on the final value of the diametrical overcut while peak current and frequency parameters have a negligible effect.


2008 ◽  
Vol 202 (1-3) ◽  
pp. 398-401 ◽  
Author(s):  
S.K. Mukherjee ◽  
S. Kumar ◽  
P.K. Srivastava ◽  
Arbind Kumar

Author(s):  
Shivraj Yeole ◽  
Nagabhushana Ramesh Nunna ◽  
Balu Naik Banoth

Electrical Discharge Micro Drilling (EDMD) is considered as one of the most effective method for machining difficult to cut and hard materials like titanium alloy. However, selection of process parameters for achieving superior surface finish, higher machining rate and accuracy is a challenging task in drilling micro-holes. In this paper, an attempt is made to optimize micro-EDM process parameters for drilling micro holes on titanium grade 19 alloy. In order to verify the optimal micro-EDM process parameters settings, material removal rate (MRR), electrode wear rate (EWR) and over cut (OC) were chosen as the responses to be observed. Pulse on time, pulse off time, electrode diameter and current were selected as the governing process parameters for evaluation by Taguchi method. Nine micro holes of 300 μm, 400 μm and 500 μm were drilled using L9 orthogonal array (OA) design. Optimal combination of machining parameters were obtained through Signal-to-Noise (S/N) ratio analysis. It is seen that machining performances like material removal rate and overcut are affected by the peak current whereas electrode wear is affected by peak current and electrode diameter. Morphology of the micro holes has been studied through SEM micrographs of machined micro-hole.


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