Vishal S. Sharma

Estimation of cutting forces and surface roughness for hard turning using neural networks

Metal cutting mechanics is quite complicated and it is very difficult to develop a comprehensive model which involves all cutting parameters affecting machining variables. In this study, machining variables such as cutting forces and surface roughness are measured during turning at different cutting parameters such as approaching angle, speed, feed and depth of cut. The data obtained by experimentation is analyzed and used to construct model using neural networks. The model obtained is then tested with the experimental data and results are indicated.

Cutting tool wear estimation for turning

The experimental investigation on cutting tool wear and a model for tool wear estimation is reported in this paper. The changes in the values of cutting forces, vibrations and acoustic emissions with cutting tool wear are recoded and analyzed. On the basis of experimental results a model is developed for tool wear estimation in turning operations using Adaptive Neuro fuzzy Inference system (ANFIS). Acoustic emission (Ring down count), vibrations (acceleration) and cutting forces along with time have been used to formulate model. This model is capable of estimating the wear rate of the cutting tool. The wear estimation results obtained by the model are compared with the practical results and are presented. The model performed quite satisfactory results with the actual and predicted tool wear values. The model can also be used for estimating tool wear on-line but the accuracy of the model depends upon the proper training and section of data points.

Cryogenic Treatment of Tool Materials: A Review

Cryogenic treatment (CT) of materials has shown significant improvement in their properties. Various advantages like increase in wear resistance, reduced residual stresses, increase in hardness, fatigue resistance, toughness imparted by transformation of retained austenite to martensite, precipitation of carbides, eta-carbide formation, perfect distributed/homogenous crystal structure, better thermal conductivity, and reduced chemical degradation. Moreover, this technology is an eco-friendly, nontoxic, and nonexplosive. Different approaches have been applied for CT to study the effect on different types of steel and other materials. In recent years, researchers have tried to evaluate the process to optimize the parameters. This paper brings out the comprehensive analysis of the strategies followed in CTs and their significant effects on properties of materials by differentiating CT from cryogenic conditioning of the process. The final part of the paper discusses the developments and outlines the trends for further research in this field.

A Review on Minimum Quantity Lubrication for Machining Processes

In the pursuit toward achieving dry cutting, air machining, minimum quantity lubrication (MQL), and cryogenically cooled machining are the stepping stones. Nevertheless, machining is always accompanied by certain difficulties, and hence none of these methods has provided a complete solution. Hence, this article reviews various MQL methods used by various machining processes for different materials. It also highlights the future work directions for research in this area.

Residual Stresses, Surface Roughness, and Tool Wear in Hard Turning: A Comprehensive Review

Hard turning is used in the manufacturing industry as an economic alternative to grinding, but the reliability of hard turning processes is often unpredictable. The main factors affecting the reliability of hard turning are surface integrity and tool wear. In the present study, an attempt has been made to investigate the effect of cutting parameters on surface roughness, tool wear, and residual stress distribution in hard turning. This article brings out the comprehensive analysis of the effects of cutting parameters on surface roughness, residual stress, and tool wear.

Design optimization of cutting conditions and analysis of their effect on tool wear and surface roughness during hard turning of AISI-H11 steel with a coated—mixed ceramic tool

Abstract The present study is an attempt to model the tool wear and surface roughness, through response surface methodology (RSM) during hard turning of AISI-H11 steel with TiN-coated—mixed ceramic inserts. The effect of machining parameters — i.e. cutting speed, feed rate, depth of cut, and workpiece hardness — on the response factors, viz. flank wear and surface roughness, have been investigated by applying analysis of variance (ANOVA) and through factor interaction graphs in the RSM. The non-linear quadratic models best fit the experimental data points. The desirability function approach has been used for multiple response factors optimization. The confirmation experiments carried out to check the validity of developed models predicted response factors within 5 per cent error. The feed rate, depth of cut, and workpiece hardness are observed to have a statistically significant impact on the flank wear, whereas feed rate and workpiece hardness are the significant factors affecting the surface roughness. The tool wear was monitored with a toolmakers microscope, and wear characterization of some of the representative inserts was carried out using scanning electron microscope/energy dispersive X-ray (SEM-EDX) analysis. The tool appears to be worn out by abrasion, notch wear, and chipping of the tool surface owing to rubbing and impingement of hard particles in the work material and also by adhesion wear.

Machining Parameters Optimization of Titanium Alloy using Response Surface Methodology and Particle Swarm Optimization under Minimum-Quantity Lubrication Environment

The present paper depicts an application of response surface methodology (RSM) and particle swarm optimization (PSO) technique for optimizing the machining factors in turning of titanium (Grade-II) alloy using cubic boron nitride insert tool under minimum quantity lubricant (MQL) environment. The three machining factors, i.e., cutting speed (Vc), feed rate (f) and side cutting edge angle (approach angle π), are designed as three factors by using RSM design, which is withal subject to several constraints including tangential force (Fc), tool wear (VBmax), surface roughness (Ra) and tool-chip contact length (L). The multiple regression technique was used to establish the interaction between input parameters and given responses. Moreover, the results have been presented and optimized process parameters are acquired through multi-response optimization via desirability function as well as the PSO technique. The lower values of Vc (200 m/min), f (0.10 mm/rev) and higher values of ϕ (90°) are the optimum machining factors for minimizing the aforementioned responses. It was also observed that the selected responses predicated on PSO are much closer as that of the values acquired in view of the desirability function approach. Henceforth, PSO has the potential to cull appropriate machining factors while turning titanium (Grade-II) alloys under MQL conditions.

Advances in the turning process for productivity improvement — a review

Increasing productivity and reducing manufacturing cost have always been keys to successful business. In machining, higher values of cutting parameters offer opportunities for increasing productivity, but this also involves greater risk of deterioration in surface quality and tool life. During the past decade significant advances have been made in the development of cutting tool materials for machining of ‘difficult-to-cut’ materials. The cost involved in the production of new turning tools is very high. To overcome this cost factor researchers have tried to bring about modifications in the turning process using existing tool materials. A good understanding of the cutting conditions, temperature generation, failure modes, and cutting forces leads to efficient control of the turning process. The literature reveals that modifications in the tool geometry (such as grooved/restricted contact tools (RCTs) and chamfered/honed edges), applications of cooling techniques, ultrasonic assisted turning (UAT), hot machining, and cryogenic treatment of inserts have led to efficient and economic machining of modern materials used for aerospace, steam turbine, bearing industry, nuclear, and automotive applications. This paper presents a review of the different techniques involved in turning which can supplement the performance of cutting tools for improved economics, good surface finish, and surface integrity during machining of the latest materials.

Finish Hard Turning of Continuous and Interrupted Surfaces with Cubic Boron Nitride (CBN) and Coated Carbide Tools

In this article, cubic boron nitride (CBN) and coated carbide tools were used for finish turning of hardened steel with continuous and interrupted surfaces. The objective of this work is to investigate the conditions under which carbide tools can give optimal results in terms of both tool wear and surface integrity of the machined surface in comparison to costly CBN tools. The turning performance was evaluated in terms of maximum flank wear of the tools as well as surface integrity issues of the machined surface like white layer formation, microhardness decrease, and surface roughness increase. The results indicated that the longest tool life was achieved with CBN tool, but the accumulated machining time of all the four cutting edges in carbide tool was comparable with that of CBN tool. Significant affect of surface interruptions on tool life of carbide tool was observed, while life of CBN tool was not much affected by surface interruptions. The surface integrity achieved with carbide tools was comparable with that of CBN tools. The surface roughness value observed with both tools was below 1.6 µm. No white layer was observed while turning the interrupted and fully interrupted surfaces with both tools.

Optimization and Analysis of Shrinkage in Selective Laser Sintered Polyamide Parts

Decreasing shrinkage during selective laser sintering process improves quality and functionality of the product. A model has been purposed to predict the shrinkage in terms of process parameters such as laser power, scan spacing, bed temperature, hatch length, and scan count. Face centered central composite design response surface methodology was employed to develop a model, and the adequacy of the model was verified using analysis of variance. The experiments were conducted on duraform polyamide material by using vanguard HS SLS machine by 3D systems. The effects of the different process parameters on shrinkage were analyzed and optimized.