Precise Internal Turning of Axi-symmetric SS316 Thin-walled Component: Experimentations on ED-Machining Setup

ABSTRACT

Axis-symmetric thin-walled cylindrical components like couplers and concentric reducers are needed in mechanical assemblies. These components do not have enough rigidity to hold in the chuck for conventional machining. It is difficult to control their radial dimensions accurately and cost-effectively. In this work, an attempt is made to enlarge the diameter of axis-symmetric thin-walled cylindrical components. Electric discharge machining (EDM) with a centreless turning attachment is utilised. Three variables were selected as input variables: impulse current (IP), pulse on time (Ton), and pulse off count (Toff count). Workpiece RPM, electrode gap, spark, lift, and machining time were constant parameters. Response surface methodology (RSM) was used in planning the experiments. The response variables were material removal rate (MRR), enlargement in diameter (EN), and circularity (Cir). It was found that MRR and EN increase with the increase in IP and Ton and decrease with the rise in Toff time. The values of optimum process parameters found at impulse current (15 A), pulse on time (490 µs) and pulse off count (6) were MRR (366 mg/min), enlargement in diameter (229 µm) and circularity (0.014 µm). Moreover, the sample’s topography changed as hardness and corrosion resistance increased.

KEYWORDS:

• Axis symmetric thin-walled cylindrical components
• Electric discharge machining
• Electric discharge assisted centreless turning
• Response surface methodology

Acknowledgements

We gratefully acknowledge the contributions of the Department of Science and Technology entitled DST-SERB EMR/2016/003372.

Disclosure statement

The results reported in this article were not influenced by competing financial interests or personal relationships between the authors.