Flow Field Simulation And Experimental Investigation On Macro Electrolyte Jet Electrochemical Turning of TB6 Titanium Alloy

Electrolyte jet electrochemical turning is an effective method to realize high-quality machining of titanium alloy rotating components; however, minimal research has been carried out in this field. This is because it is difficult to control the machining flow field, which leads to poor machining surface quality. In this work, numerical simulations were used to optimize the machining flow field and reduce the proportion of gas that mixed into the machining area. This can promote participation of the tool electrode tip in the electrochemical reaction and improve the machining efficiency. The effectiveness of the optimized machining flow field for jet electrochemical turning was verified experimentally. The results showed that all three kinds of revolving TB6 titanium alloy samples with different structures could maintain the original contour shape, with a contour error <1% and a machined surface roughness reaching Ra 2.414 μm. The results demonstrate the application potential of the jet electrochemical turning process.

Experimental and analytical investigations into wire electrochemical micro turning

Electrochemical turning (ECT) has been studied by researchers for making axially symmetric parts of different materials by using shaped tools fed radially into the rotating workpiece. Despite having various advantages over other advanced machining processes, ECT has failed to gain much attention by the manufacturing industries and researchers because of the complexity involved in designing a shaped tool to give a desired shape and tolerances to the workpiece. In the present work, a systematic study is presented to understand the applicability of a microwire as a replacement for a shaped tool in this process. Simulations are carried out to understand the distribution of electric field lines and current density in case of wire electrochemical turning (ECT). The effects of insulting wire up to different angles on the evolved groove profile are investigated by performing simulation study. Minimum groove width is observed at the lowest value of ‘tool exposed angle’ (30°), while maximum groove depth is observed at the highest value of tool exposed angle (270°). In the later part of the work, an experimental study is performed to characterize a groove profile using a bare copper wire of diameter 200 µm. The effects of input parameters, such as workpiece rpm, tool radial insertion, applied potential and electrolyte concentration on responses like groove width, corner radius and taper angle are investigated. Finally, the understanding of behaviour of different process parameters is applied to perform operations like multi-step turning, microgroove turning and taper turning on copper and micro-threading on stainless steel 304.

Statistical Monitoring and Optimization of Electrochemical Machining using Shewhart Charts and Response Surface Methodology

The response surface methodology (RSM) and Shewhart control charts have been widely used in manufacturing to reduce variation, improve quality and optimize the output. This article proposes an application of individuals & moving range chart (I&MR) and RSM in electrochemical machining. The Shewhart-type I&MR control chart and RSM are combined together in an effective way to successfully guarantee the statistical control of the surface roughness (Ra) of the items produced by wire electrochemical turning, and meanwhile optimize Ra by exploring the optimal values of the machining parameters including applied voltage, wire feed rate, wire diameter, rotational speed and overlap distance. The conducted experiments reveal that the optimal values of the aforementioned factors are 23.67, 0.5, 0.2, 900 and 0.02, respectively. A second-order regression model is also developed to predict the output (Ra) at different combinations of the input parameters. The developed regression model can predict the output values with a determination coefficient (R2) of 96.9%. The proposed combined scheme of Shewhart charts and RSM can be employed in other manufacturing processes and even in different service sectors to efficiently enhance the performance and reduce the cost.