The present work concerns an experimental study of hard turning with CBN tool of AISI 52100 bearing steel, hardened at 64 HRC. The main objectives are firstly focused on delimiting the hard turning domain and investigating tool wear and forces behaviour evolution versus variations of workpiece hardness and cutting speed. Secondly, the relationship between cutting parameters (cutting speed, feed rate and depth of cut) and machining output variables (surface roughness, cutting forces) through the response surface methodology (RSM) are analysed and modeled. The combined effects of the cutting parameters on machining output variables are investigated while employing the analysis of variance (ANOVA). The quadratic model of RSM associated with response optimization technique and composite desirability was used to find optimum values of machining parameters with respect to objectives (surface roughness and cutting force values). Results show how much surface roughness is mainly influenced by feed rate and cutting speed. Also, it is underlined that the thrust force is the highest of cutting force components, and it is highly sensitive to workpiece hardness, negative rake angle and tool wear evolution. Finally, the depth of cut exhibits maximum influence on cutting forces as compared to the feed rate and cutting speed.

Statistical analysis of surface roughness and cutting forces using response surface methodology in hard turning of AISI 52100 bearing steel with CBN tool

Analysis of surface roughness and cutting force components in hard turning with CBN tool: Prediction model and cutting conditions optimization

In the present contribution, numerical and experimental methodologies concerning orthogonal cutting are proposed in order to study the dry cutting of an aeronautic aluminium alloy (A2024-T351) The global aim concerns the comprehension of physical phenomena accompanying chip formation according to cutting velocity variation For the numerical model, material behaviour and its failure criterion are based on the Johnson–Cook law The model proposes a coupling between material damage evolution and its fracture energy A high-speed camera was used to capture the chip formation sequences The numerical results show that the chip–workpiece contact and the tool advancement induce bending loads on the chip Consequently, a fragmentation phenomenon takes place above the rake face when the chip begins to curl up The computed results corroborate with experimental ones The numerical results predict the residual stress distribution and show high values, along the cutting direction, on the machined workpiece surface

Numerical and experimental study of dry cutting for an aeronautic aluminium alloy (A2024-T351)

Hard turning is gaining grounds for machining hardened steels as it has several benefits over grinding. There are several issues, which should be understood and dealt with, to achieve successful performance of the process. Researchers have worked upon several aspects related to hard turning. The present work is an effort to review some of these works and to understand the key issues related to process performance. The review shows that the type of tool material, cutting edge geometry and cutting parameters affect the process efficiencies in terms of tool forces, surface integrities integrity, and white layer. Adequate machine rigidity is a must essential to minimize the process inaccuracies. Also moreover, for finish hard turning, where the depth of cut is less than the nose radius of the tool, the forces deviate from the conventional trends as the radial force component is the maximum and axial force component becomes minimum. The present work finally lists down certain areas that can be taken up for further research in hard turning.

State of the art in hard turning

Some studies on hard turning of AISI 4340 steel using multilayer coated carbide tool

Hard machining of hardened bearing steel using cubic boron nitride tool

The present paper is a contribution to the investigation of physical phenomena accompanying sawtooth chip formation in the case of hard turning. The study concerns the machining with coated carbide of tempered AISI 4340 steel with a Rockwell C hardness of 47 HRC. The main idea in this paper deals with the establishment of a direct relationship between serrated-chip morphology simultaneously with force component signals derived from acquisition at high frequency and with the width of facets detected on a workpiece machined surface. This experimental work was supported by a numerical simulation based on Abaqus/ Explicit software. Numerical results dealing with effect of temperature evolution on the chip morphology show that the beginning of the sawtooth chip initiation is due to an adiabatic shear at the tool tip with propagation pathway towards the free surface. In addition, computed results have a good corroboration with those obtained experimentally.

Experimental and numerical study of chip formation during straight turning of hardened AISI 4340 steel

In this study, an attempt has been made to statistically model the relationship between cutting parameters (speed, feed rate and depth of cut), cutting force components (Fx, Fy and Fz) and workpiec...

Mathematical modeling for turning on AISI 420 stainless steel using surface response methodology

An experimental investigation was designed to establish the distribution of mechanical properties throughout a high-density polyethylene (HDPE) gas pipe wall. The proposed approach used a continuous and uniform filament that was automatically machined from the pipe on a precision lathe at a very low cutting speed and an optimal depth of cut to minimize heating and structural disturbances. Typical engineering stress–strain curves, in every layer, were obtained on a testing machine especially designed for polymers, and they were statistically analyzed. The stress–strain behavior of HDPE pipe material could basically be divided into three distinctive zones, the second of which remained important. The average stress level illustrating cold drawing for a given layer was almost constant throughout the pipe wall. The measured stresses and moduli correlated very well with the pipe thickness, and they increased from the outer layers toward the inner layers. This was explained by the crystallinity evolution because the pipe production process was based on a convective water-cooling system with a temperature gradient, which generated residual stresses. Computed statistical stress–strain correlations at yielding, the onset of cold drawing, and fracture points revealed acceptable linear relations for an error level of p ≤ 0.05. On the other hand, an increasing linear correlation characterized the relationship of the yield stress and elastic modulus. This result was confirmed by literature for standard specimens, prepared by compression molding, that did not represent an actual pipe structure with respect to an extrusion thermomechanical history. Such an approach to mechanical property variability within an HDPE pipe wall highlighted the complexity of the hierarchical structure behavior in terms of stress–strain and long-term brittle failure. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 272–281, 2005

Experimental approach to mechanical property variability through a high-density polyethylene gas pipe wall

Alumina-based mixed ceramic (CC650) and cubic boron nitride-based (CBN) (CBN7020) tools are becoming mostly preferred for machining under severe conditions. The aim of this study is to investigate the effect of cutting parameters on ceramic and CBN tool wear in the hard turning of X200Cr12 steel. The results indicate that the comparison span for both tool materials is limited to a speed of 180 m/min at which catastrophic ceramic cutting edge collapse took place. The tool life ratio rose from 4.37 to 17.14 when the cutting speed evolved from 90 to 180 m/min in favour of CBN, which resisted up to a cutting speed of 350 m/min. The feed rate effect on roughness (μm) is satisfactorily predicted by a power model deduced from experimental data and is compared with a theoretical model. A correlation between surface roughness and tool wear is proposed for the usual cutting speed ranges and for the two tested inserts respectively. The analysis also revealed that, under the allowable wear limit, the ceramic ...

The effects of cutting conditions on mixed ceramic and cubic boron nitride tool wear and on surface roughness during machining of X200Cr12 steel (60 HRC)

Lakhdar Boulanouar

Papers

Hard machining of hardened bearing steel using cubic boron nitride tool

Experimental and numerical study of chip formation during straight turning of hardened AISI 4340 steel

Mathematical modeling for turning on AISI 420 stainless steel using surface response methodology

Experimental approach to mechanical property variability through a high-density polyethylene gas pipe wall

The effects of cutting conditions on mixed ceramic and cubic boron nitride tool wear and on surface roughness during machining of X200Cr12 steel (60 HRC)