Modelling of cutting forces and surface roughness evolutions during straight turning of Stellite 6 material based on response surface methodology, artificial neural networks and support vector machine approaches

Brahim Ben Fathallah,R Saidi R Saidi,M.a Yallese M.A Yallese,T Mabrouki T Mabrouki,S Belhadi S Belhadi

doi:10.15282/jmes.15.4.2021.07.0673

Abstract

The present research work proposes an experimental investigation helping to comprehend fundamental impacts of operating conditions during the cutting of cobalt alloys (Stellite 6). Thus, an experimental design was adopted to allow to build predicted mathematical models for the outputs, which are the average peak-to-valley profile roughness (Rz) and the tangential cutting force (Ft). Artificial neural network (ANN), support vector machine (SVM) and response surface methodology (RSM) were exploited to model the pre-cited outputs according to operation parameters. As a result, it has been highlighted that both feed rate and cutting depth, considerably, affect tangential cutting force evolution. Moreover, results show that both the insert feed rate and nose radius, are higher. This means the average peak-to-valley profile roughness is higher. In order to put out the effect of operating parameters on cutting outputs, Analysis of variance (ANOVA) method has been employed. This has allowed the detection of significant cutting conditions affecting average peak-to-valley profile roughness and tangential cutting force. In fact, to highlight the performance of adopted mathematical approaches, a comparison between RSM, ANN, and SVM has been also established in this study.

Highlights

Cobalt alloys are largely used in the aerospace industry for many applications to require an excellent mechanical strength, corrosion and oxidation resistance at high temperatures [1, 2]
Our study focuses on the establishment of cutting models modelling allowing to predict the evolution of process responses such as the average peak-to-valley profile roughness (Rz) and the tangential force (Ft) according to finishing cutting conditions
Modelling techniques of outputs according to the variations of operating parameters in straight turning of Stellite 6 were presented

Summary

Introduction

Cobalt alloys are largely used in the aerospace industry for many applications to require an excellent mechanical strength, corrosion and oxidation resistance at high temperatures [1, 2]. This super-alloys is specially used for nuclear reactors, electronics and chemical equipment and medical devices principally in power plants [3, 4]. The low elastic modulus of cobalt alloy (50% lower than steel) is the most significant source of vibrations generated during machining This material is sensitive to mechanical and thermal shocks due to their reduced toughness [6]. The grain size and presence of carbide formed in the Cobalt matrix of the cobalt based super alloy present a significant change in mechanical properties [7]

Methods

Results

Conclusion