Improving machining accuracy of electrochemical machining blade by optimization of cathode feeding directions

Pulsed electrochemical machining (PECM) has been conducted for invar (Fe-Ni) fine sheet consisting of 64 % Fe ions and 36 % Ni ions. Solutions of sodium chloride (NaCl), acetic acid (CH 3 COOH), sodium nitrate (NaNO 3 ), and sodium nitrite (NaNO 2 ) mixed with sodium tartrate (C 4 H 4 Na 2 O 6 ) were used as an electrolyte. First, the electrical conductivities of all electrolytes have been measured. As the concentration of each electrolyte increased, the electrical conductivities of electrolytes increased except for the acetic acid. The electrochemical machinability has been investigated using four types of electrolytes. The results of PECM show that the electrolyte which has the high electrical conductivity value leads to the low electrochemical machinability. The pulse waves which indicate the electrical characteristics during the PECM has been observed and it is confirmed that the passivating oxide film occur in PECM. To compare the capability of changing in transpassive state, the anode surface has been investigated. This study presents the relationship between electrical conductivity and electrical machinability. Moreover, the capacity of changing in transpassive state has been investigated as compared with four types of electrolytes. This study shows the possibility of applying invar fine sheet in PECM and contributes to determining the electrolyte for the process.

Section: Introductionmentioning

confidence: 99%

“…Previous studies were conducted by changing machining conditions such as the voltage, current density, pulse duration, duty factor, electrolyte concentration, and inter-electrode gap (IEG) [7][8][9][10][11]. Sodium nitrate solution has been applied for micromachining with PECM [16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Analysis of the relationship between electrolyte characteristics and electrochemical machinability in PECM on invar (Fe-Ni)fine sheet

Chun

Kim

Lee

2016

“…To maintain the ECM flow field stability and improve the machining accuracy, many studies have been carried out, including on the inter-electrode gap between cathode and workpiece [13,14], ultrasonic-assisted ECM [15], the influence of short pulsed voltage [16], magnetic field-assisted ECM [17], the relation between temperatures and copy accuracy [18], the cosθ analytical approach for machining complex grooves [19], and optimizing the cathode feeding direction [20]. A W-shaped electrolyte flow model was used to machine blisk by Zhu and Xu [21,22].…”

Section: Introductionmentioning

confidence: 99%

Electrochemical machining flow field simulation and experimental verification for irregular vortex paths of a closed integer impeller

Tang

Feng

Zhu

et al. 2015

Electrochemical machining (ECM) is an economical and effective method for machining hard-to-cut metal materials into complex shapes in aerospace and aeronautics fields, which are difficult to machine with conventional methods. As we all know, electrolyte flow field is one of the important factors in ECM irregular vortex paths of the closed integer impeller. To improve the stability of the whole processing, the flow field mathematical model was developed. The 3-D gap flow field simulation models of the reversed flow and forward flow patterns were also established, respectively. From the streamline, velocity, and pressure cloud picture of the electrolyte flow field simulation, the results showed that under the reversed pattern, the electrolyte flow velocity in the front gap and the side gap was not only higher but also more uniform than the forward pattern. Finally, the experimental verification was carried out and the experimental results were consistent with the simulation results. The whole process is stable and has no spark and no short circuit phenomenon with the reverse flow pattern. We successfully obtained 0.8-micron surface roughness of the machined workpiece. On the contrary, the irregular vortex paths cannot be successfully processed by forward flow pattern. The results indicate that reverse flow pattern is an effective and feasible method to machining irregular vortex paths of the closed integer impeller.

“…The mesh attached to the workpiece moved according to Eqs. (1) and (2). The mesh attached to the sides of the model is fixed in the x-y plane; hence, v x and v y = 0 m/s and free in v z with respect to the global coordinate system.…”

Section: Meshingmentioning

confidence: 99%

“…It can be performed with minimal effect on workpiece physical properties and zero tool wear in ideal conditions, which is negligible in practice. Applications include the manufacture of turbine blades for gas jet engines as presented by [1] and later by [2], biomedical implants as presented by [3], and everyday products such as razor blades as presented by [4]. However, in order to increase the use of ECM within industry, better material removal prediction and tool design methods are still needed.…”

Section: Introductionmentioning

confidence: 99%

3D multiphysics model for the simulation of electrochemical machining of stainless steel (SS316)

Gomez-Gallegos

Mill

Mount

et al. 2017

In electrochemical machining (ECM)-a method that uses anodic dissolution to remove metal-it is extremely difficult to predict material removal and resulting surface finish due to the complex interaction between the numerous parameters available in the machining conditions. In this paper, it is argued that a 3D coupled multiphysics finite element model is a suitable way to further develop the ability to model the ECM process. This builds on the work of previous researchers and further claims that the overpotential available at the surface of the workpiece is a crucial factor in ensuring satisfactory results. As a validation example, a real-world problem for polishing via ECM of SS316 pipes is modelled and compared to empirical tests. Various physical and chemical effects, including those due to electrodynamics, fluid dynamic, and thermal and electrochemical phenomena, were incorporated in the 3D geometric model of the proposed tool, workpiece, and electrolyte. Predictions were made for current density, conductivity, fluid velocity, temperature, and crucially, with estimates of the deviations in overpotential. Results revealed a good agreement between simulation and experiment and these were sufficient not only to solve the immediate real problem presented but also to ensure that future additions to the technique could in the longer term lead to a better means of understanding a most useful manufacturing process.