Research on Electrochemical Machining of Deep Small Holes with Positive and Negative Pulse Power

Machining Accuracy ◽

Negative Pulse ◽

Mass Removal ◽

Nickel Based Alloy ◽

Accuracy And Stability ◽

Small Holes

Background: High-temperature alloy such as nickel-based alloy has become the main material for core components such as aero engines due to their high strength and good toughness. Therefore, it is of great significance to study how to improve the machining accuracy and stability of electrochemical machining (ECM) of deep small holes on the nickel-based alloy. The instantaneous high-density current during the pulse width of pulse ECM is beneficial to the dissolution of metal workpieces. Many experts and scholars have studied the pulse ECM of deep small holes. Objective: The purpose of this article is to propose and design a Positive And Negative Pulse (PANP) power supply to study the accuracy and stability of ECM of deep small holes on nickel-based alloys. Methods: First of all, an H-bridge composed of four MOSFET switches is designed to achieve PANP output in the main circuit of the power supply. Then, this paper studies the influence of the ratio of positive and negative pulses on short circuits, the influence of the ratio of positive and negative pulses on the mass removal rate, and the influence of the electrolyte concentration and pulse width on the mass removal rate. Finally, according to the obtained optimal parameters, the influence of electrolyte pressure on the average radial overcut of hole depth is analyzed. Results: The experimental results showed that the short-circuit frequency is reduced by more than 50% compared with non-negative pulse power supply; the ratio of positive and negative pulses, pulse width and electrolyte concentration and pressure were optimized by experiments to improve the mass removal rate of the workpiece and the average radial overcut of hole depth. Conclusion: The designed PANP power supply can improve the machining accuracy and stability of ECM of deep small holes on nickel-based alloys.

Design and its Experiments of Micro Electrochemical Machining System

10.4028/www.scientific.net/amr.97-101.2505 ◽

2010 ◽

Vol 97-101 ◽

pp. 2505-2508 ◽

Author(s):

Yuan Bo Li ◽

Yong Jun Zhang ◽

Zhong Ning Guo

Keyword(s):

High Resolution ◽

Power Supply ◽

Pulse Width ◽

Short Pulse ◽

Pulse Frequency ◽

Machining Accuracy ◽

Micro Ecm ◽

Machining System ◽

Short Pulse Width

A micro Electrochemical Machining (ECM) system has been developed, and macro/micro complex feed mechanism has been presented in order to achieve high-resolution. A nanosecond pulse power supply for micro-ECM has been developed, and the minimum pulse width can reach 50 ns. Complementary chopper circuit has been designed to avoid waveform distortion, which can achieve higher pulse frequency. A series of ECM experiments using the machining system have been carried out, and results of tests have proved that high-resolution spindle, and high frequency, short pulse width power supply help to achieve better quality surface, higher machining accuracy.

Study of Pulse Electrochemical Machining Performance of Deep-Small Hole on Nickel-Based Alloy

10.4028/www.scientific.net/amr.204-210.1830 ◽

2011 ◽

Vol 204-210 ◽

pp. 1830-1834

Author(s):

Zhao Long Li ◽

Shi Chun Di

Keyword(s):

Base Alloy ◽

Removal Rate ◽

Machining Process ◽

Machining Accuracy ◽

Machining Performance ◽

Math Model ◽

Technical Parameters ◽

Pulse Electrochemical Machining ◽

Small Holes

The method of machining deep hole on Ni-base alloy which can tolerant high temperature by pulse electrochemical machining has been proposed in this paper. Five technical parameters are discussed on the effect of mass removal rate of machining process. Establish a dynamic math model, and analyze the effect of process parameters on the mass material removal rate of deep small holes. Machining accuracy of deep small holes was analyzed.

Research on Multi-Physics Coupling Simulation for the Pulse Electrochemical Machining of Holes with Tube Electrodes

Micromachines ◽

10.3390/mi12080950 ◽

2021 ◽

Vol 12 (8) ◽

pp. 950

Author(s):

Zhaolong Li ◽

Bingren Cao ◽

Ye Dai

Keyword(s):

Current Density ◽

Power Supply ◽

Film Cooling ◽

Simulation Analysis ◽

Removal Rate ◽

Inlet Pressure ◽

Duty Ratio ◽

Side Gap ◽

Accuracy And Stability

Electrical parameters of the power supply are significant factors affecting the accuracy and stability of the electrochemical machining (ECM). However, the electric field, flow velocity and temperature in the machining area are difficult to measure directly under the influence of the power supply. Therefore, taking the film cooling hole as an example, the multi-physics coupling simulation analysis of the ECM is performed on the basis of Faraday’s law and fluid heat transfer mathematical model. The machining characteristics of the direct current and pulse ECM are compared through simulation. The results show that the pulse ECM improves the distribution of temperature and current density in the machining area. The period has little effect on the temperature, current density and side removal rate. The side removal rate increases with the increase of the duty ratio and lateral gap. Increasing of the duty ratio and decreasing of the lateral gap will increase the temperature and current density. Increasing the inlet pressure accelerates the frequency of renewal of heat and electrolysis products, which can reduce the single side gap. The experience of the ECM holes verifies the results of the simulation. The accuracy and stability of the ECM of holes are enhanced by optimizing the duty ratio, lateral gap and inlet pressure.

Experimental Investigations on Aircraft Blade Cooling Holes and CFD Fluid Analysis in Electrochemical Machining

Advances in Materials Science and Engineering ◽

10.1155/2019/4219323 ◽

2019 ◽

Vol 2019 ◽

pp. 1-11

Author(s):

Mingxia Chai ◽

Zhiyong Li ◽

Hongjuan Yan ◽

Xiaoyu Sun

Keyword(s):

Flow Field ◽

Solution Concentration ◽

Geometrical Model ◽

Experimental Investigations ◽

Machining Accuracy ◽

Flow State ◽

Hole Making ◽

Cooling Hole ◽

Accuracy And Stability

The flow field distribution in an interelectrode gap is one of the important factors that affect the machining accuracy and surface quality in the electrochemical machining (ECM) process for aircraft blades. In the ECM process, some process parameters, e.g., machining clearance, processing voltage, and solution concentration, may result in electrolyte fluid field to be complex and unstable, which makes it very difficult to predict and control the machining accuracy of ECM. Therefore, 30 sets of experiments for cooling hole making in ECM were carried out, and furthermore, the machining accuracy and stability of cooling hole were concentrated. In addition, the flow channel of the geometrical model of the gap flow field was established and analyzed according to the electrolyte flow state simulation by CFD. The effects of the flow velocity mode on the machining accuracy and stability for cooling hole making were investigated and determined in detail.

Experimental investigation of the electrochemical micromachining process of Ti-6Al-4V titanium alloy under the influence of magnetic field

Materials Science-Poland ◽

10.2478/msp-2021-0013 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

T. Praveena Gopinath ◽

J. Prasanna ◽

C. Chandrasekhara Sastry ◽

Sandeep Patil

Keyword(s):

Magnetic Field ◽

Titanium Alloy ◽

Removal Rate ◽

Machining Process ◽

Electrochemical Micromachining ◽

Machining Accuracy ◽

Micro Hole ◽

Neodymium Magnets ◽

Pulse On Time

Abstract An attempt has been made to study the influence of magnetic field on the micro hole machining of Ti-6Al-4V titanium alloy using electrochemical micromachining (ECMM) process. The presence of magneto hydro dynamics (MHD) is accomplished with the aid of external magnetic field (neodymium magnets) in order to improve the machining accuracy and the performance characteristics of ECMM. Close to ideal solution for magnetic and nonmagnetic field ECMM process, the parameters used are as follows: concentration electrolyte of 15 g/l; peak current of 1.35 A; pulse on time of 400 s; and duty factor of 0.5. An improvement of 11.91–52.43% and 23.51–129.68% in material removal rate (MRR) and 6.03–21.47% and 18.32–33.09% in overcut (OC) is observed in ECMM of titanium alloy under the influence of attraction and repulsion magnetic field, respectively, in correlation with nonmagnetic field ECMM process. A 55.34% surface roughness factor reduction is ascertained in the hole profile in magnetic field-ECMM in correlation with electrochemical machined titanium alloy under nonmagnetic field environment. No machining related stress is induced in the titanium alloy, even though environment of electrochemical machining process has been enhanced with the presence of magnetic field. A slight surge in the compressive residual factor, aids in surge of passivation potential of titanium alloy, resulting in higher resistance to outside environment.

Electrochemical Drilling of Deep Small Holes in Titanium Alloys with Pulsating Electrolyte Flow

Advances in Mechanical Engineering ◽

10.1155/2014/167070 ◽

2014 ◽

Vol 6 ◽

pp. 167070 ◽

Author(s):

Yongbin Zeng ◽

Xiaolong Fang ◽

Yudong Zhang ◽

Ningsong Qu

Keyword(s):

Titanium Alloys ◽

Removal Rate ◽

Machining Accuracy ◽

Pulsation Frequency ◽

Average Pressure ◽

Electrolyte Flow ◽

Product Removal ◽

Electrochemical Drilling ◽

By Products ◽

Small Holes

Inherent characteristics of electrochemical drilling (ECD) mean that it is a major solution to the machining of deep small holes in difficult-to-cut materials. The removal of insoluble by-products from the machining gap determines the accuracy of control and limits process capacity. Pulsating electrolyte flow is introduced to enhance the removal rate of insoluble products by reducing the hold-down pressure caused by the electrolyte. Experiments are conducted to optimize a stimulus signal for the pulsation and to investigate the electrolyte pulsation frequency, pulsation amplitude, applied voltage, and electrode feed rate in the machining of deep small holes. The results indicate that optimized pulsating flow is effective in accelerating by-product removal and enhancing machining accuracy and maximum machining depth. With the optimized parameters of 5 Hz in frequency, 0.2 MPa in amplitude, and 0.5 MPa in average pressure, a deep hole was machined in titanium alloys of 20 mm depth and 1.97 mm averaged diameter.

Recent Patents on Electrochemical Machining of Shaped Holes

Recent Patents on Mechanical Engineering ◽

10.2174/2212797613999201130114214 ◽

2020 ◽

Vol 13 ◽

Author(s):

Zhaolong Li ◽

Bingren Cao

Keyword(s):

Development Trend ◽

Electrolyte Composition ◽

Machining Accuracy ◽

Tool Electrode ◽

Technological Equipment ◽

Conductive Materials ◽

Properties Of Materials ◽

The Development Trend ◽

Accuracy And Stability

Background : Electrochemical machining (ECM)can machine most conductive materials and is not limited by physical properties of materials such as strength, hardness and toughness. However, the process of ECM is unstable that the structure of tool electrode, electrolyte composition and the machining device of ECM will affect machining accuracy and stability of shaped holes. Therefore, people pay more and more attention to the development trend of ECM of shaped holes. Objective: In order to increase machining accuracy and machining stability of ECM of shaped holes, ECM method has been constantly improved. Methods: This paper reviews various representative patents and papers on ECM of shaped holes at home and abroad. Results: By summarizing a large number of patents and papers about ECM of shaped holes, this paper analyzes the structure of tool electrode, electrolyte composition and the machining device of ECM, and the development trend of ECM of shaped holes is also discussed. Conclusion: The optimization of the technological equipment and process of ECM of shaped holes is beneficial to improve the machining accuracy and the machining stability of shaped holes. More interrelated patents on ECM of shaped holes will be invented later.

Proceedings of the Institution of Mechanical Engineers Part B Journal of Engineering Manufacture ◽

Influence of different featured tools on machining accuracy in electrochemical milling

10.1177/0954405419892798 ◽

2019 ◽

pp. 095440541989279

Author(s):

Koushik Mishra ◽

Biplab Ranjan Sarkar ◽

B Bhattacharyya

Keyword(s):

Tool Path ◽

Removal Rate ◽

Research Work ◽

Machining Accuracy ◽

Layer By Layer ◽

Mixed Electrolyte ◽

The Impact ◽

Tool Rotation ◽

Electrochemical Milling

Drawbacks of electrochemical machining can be conquered to a large extent with the introduction of electrochemical milling technique. In this method, a simple shaped tool follows a predetermined tool path and material gets removed atom-by-atom from anode workpiece by electrochemical reactions through layer-by-layer approach. Keeping in mind the rising trend of electrochemical milling technique, this research work focuses to investigate the impact of major process parameters of electrochemical milling, for example, feed rate and milling layer depth on foremost responses like material removal rate and width overcut during electrochemical milling of Nimonic-263 alloy. In this research work, three different types of featured tools have been utilized and for each tool, ANSYS simulation has been carried out for analysing their impact on machining accuracy. Furthermore, these obtained simulated results have been confirmed by experimentation. Finally, an attempt has been made to produce more accurate ‘L’-shaped features on Nimonic-263 alloy with the aid of tool rotation and inner-spraying featured tools. This study confirms that mixed electrolyte, that is, NaCl(1M) + NaNO3(1M), tool rotation with internal flushing, number of outlets and the structure of the end face of the tool generate excellent machining accuracy with super finished surface with Ra value in the order of 0.07–0.08 µm during electrochemical milling of Nimonic-263 alloy.

Research of Pulse Inversion Power Supply of ECM and its Techniques

10.4028/www.scientific.net/amr.76-78.630 ◽

2009 ◽

Vol 76-78 ◽

pp. 630-634 ◽

Author(s):

Yong Jun Zhang ◽

Yong Jun Tang ◽

Zhong Ning Guo ◽

Xiao Kang Liu ◽

Feng Li

Keyword(s):

Surface Quality ◽

Power Supply ◽

High Frequency ◽

Short Pulse ◽

Machining Accuracy ◽

Electrochemical Mechanical Polishing ◽

Pulse Inversion ◽

Compact Size ◽

Supply Model

In order to improve machining accuracy and surface quality effectively in ECM (electrochemical machining), a novel pulse inversion power supply has been presented, which has following merits such as high-frequency short pulse, high-power, and compact size. The scheme of full bridge inversion has been selected in this power supply model, and feedback circuit realizes voltage adjusted automatically, and guarantees to stability of voltage. Protect circuit has designed to avoid the problem of workpiece-burn. Finally, a series of electrochemical mechanical polishing tests using the power supply have been carried out, and the results have proved that it helps to achieve well surface quality processed, and improve machining accuracy, and also verify feasibility of its scheme.

Development of a Prototype of Electrochemical Machining

10.4028/www.scientific.net/amr.223.940 ◽

2011 ◽

Vol 223 ◽

pp. 940-949 ◽

Author(s):

Silva Neto ◽

João Cirilo

Keyword(s):

Power Supply ◽

Material Removal ◽

Metal Removal ◽

State Of The Art ◽

Removal Rate ◽

Three Dimensional ◽

Electrolytic Cell ◽

Parameter Control ◽

Purification System

Electrochemical machining (ECM) is the controlled removal of material by anodic dissolution in an electrolytic cell in which the workpiece is the anode and the tool is the cathode. The ECM presents the advantages: three-dimensional surfaces with complicated profiles can be easily machined in a single operation, irrespective of the hardness and strength of the material. ECM offers a higher rate of metal removal as compared to traditional and nontraditional methods, especially when high machining currents are employed. There is no wear of the tool, which permits repeatable production. This work shows a study of development of a prototype of electrochemical machining (ECM) developed at the Federal University of Uberlândia Minas Gerais-Brazil. A state-of-the-art ECM system is the art of assemblage of facilities including a proper ECM machine, a power supply, a process parameter control system, and an electrolyte preparation, feed and purification system. With the prototype developed, the material removal rate (MRR) was studied. The MRR was influenced by tool feed rate and type of electrolyte.