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2 Electrochemical Machining Set-ups 3. ELECTROCHEMICAL ETCHING There are two types of etching mechanisms: Physical etching (or sputter etch, and relies on momentum transfer from particles hitting and eroding the surface) and wet/dry chemical etching (where reaction products formed are either soluble in the etch solution or volatile at low pressures). The removal of material from a substrate by chemical reaction or by ion bombardment is referred to as an etch process. The material that is not masked is
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This project has been made in an attempt to study the electro chemical etching & polishing in some alloys to obtain high surface finish. Electro chemical machining (ECM) is a non-conventional machining process based on the principle of electrolysis and hence it can be called as the reverse process of electroplating or anodizing. The removal of mate...
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Context 1
... shapes can be made by this process on materials regardless of their hardness. A schematic representation of ECM process is shown in Figure 1. 2 The ECM tool is positioned very close to the work piece and a low voltage, high amperage DC current is passed between the work piece and electrode. Some of the shapes made by ECM process. ...
Context 2
... Fe (OH) 2 Would form and get precipitated in the form of sludge. In this manner it can be noted that the work piece gets gradually machined and gets precipitated as the sludge. Moreover, there is not coating on the tool, only hydrogen gas evolves at the tool or cathode. Fig. 1.1 depicts the electrochemical reactions schematically. As the material removal takes place due to atomic level dissociation, the machined surface is of excellent surface finish and stress free. Cathode Reaction Na + + e -= Na; Na+H 2 O = Na (OH) +H + ;2H + +2e-=H 2 ↑ It shows that there is no deposition on tool but only gas is formed, ...
Citations
... Schematic diagram of Electrochemical Machining[5]. ...
Electrochemical machining plays an important role in production and manufacturing industries like aircraft , atomic and healthcare. Even with difficult-to-machine materials, ECM is generally preferred to machine-nickel-based alloys like Monel 400 or Monel super alloy which consists of about 67 % Nickel and 23 % Copper. It is highly unaffected to corrosion and various acids such as sulphuric acid (H 2 SO 4), hydrochloric acid (HCl) etc. due to which it is highly used in aerospace, oil production and refining, marine applications, industrial heat exchangers. Nowadays nickel hydroxides are major concerns which are toxic to environment present in sludge while machining nickel based alloys like Monel alloys and other super alloys need to be filtered before discharged into environment. This paper reviews the Electrochemical machining of Monel 400 alloy by various influencing parameters like applied voltage, current density, concentration of electrolyte, electrolyte pressure and type of electrolyte on material removal rate (MRR) tool wear rate (TWR) and surface roughness (SR). The study also suggests that the varying process parameters of ECM machining influence the various machining performances such as material removal rate (MRR) tool wear rate (TWR) and Surface finish (Ra) for Monel 400 alloy. In a recent study which utilized meta-heuristic algorithms (MFO and GWO) helped in increasing MRR by 0.242 g/min and Nickel presence by 57.72 PPM while machining Monel 400 and hence a better machining performance is obtained. The paper also aims at addressing the latest developments in machining Monel alloy as compared with conventional methods of machining and its various research challenges for further developments in non-traditional machining processes.
... This cylinder was used for digging the engraving cell on the surface of copper plated cylinder to hold the ink so that only the intentional lines would be able to transfer the ink. The engraving process could be done by mechanical, chemical, laser and electro-chemical or electro-mechanical method [3][4][5][6] The chemical etching method of engraving was based on using strong acid or mordant (e.g. ferric chloride) to remove the copper metal from a designated area of the unprotected parts of a metal surface to create a design in intaglio (gravure cylinder) www.nature.com/scientificreports/ ...
Rotogravure printing cylinders are engraved by electro-mechanical engraving (EME) process in India used for printing purpose. But this process has drawbacks of the emissions of hazardous gases, solid and water pollution. EME cylinders are better in cell size, depth and needed higher copper and chrome plating thickness. By laser engraving (LE) copper and chromium thickness were reduced by 75 µm and 5 µm in a cylinder by laser engraving with also a reduction in power consumption and plating time. The carbon footprints were also reduced by 227 g per cylinder with a cost-effective solution for rotogravure printing process.
