Suha K. Shihab

A review of turning of hard steels used in bearing and automotive applications

Hard turning is a recent technology that involves machining of hard steels using modern machine tools. Hard machining presents challenges in terms of selection of tool insert with improved tool life and high-precision machining. Turning of hardened steels using single-point cutting tool has got considerable interest among manufacturers of ball bearings, automotive, gear, and die industry. Hard turning in the automotive industry and bearing applications typically has a number of potential benefits over traditional form grinding including lower equipment costs, shorter setup time, and fewer process steps which in turn provides high flexibility and ability to cut complex geometries. Moreover, the hard turning process is usually carried out without coolant/lubricant and thus, the problem of storage, handling, and disposal of cutting fluid is eliminated, and at the same time, it probably favors the health of operators. This paper presents an overview of the past research hard turning using hard turning tools such as PCBN, cubic boron nitride, Ceramics, Carbide, etc. Major hard turning cutting materials and effect of hard turning process parameters on cutting forces, heat generation during cutting, surface finish and surface integrity, and tool wear have been discussed in light of the findings of the past research.

Investigation of surface integrity during wet turning of hard alloy steel

This paper presents a study that investigates the effect of the CNC hard turning parameters on the surface integrity (SI), defined in terms of surface roughness average (Ra) and the micro-hardness MH, of hard steel (AISI 52100) under wet cutting conditions. Nine experimental runs based on an orthogonal array of Taguchi method are performed and grey relational analysis method is subsequently applied to determine an optimal cutting parameter setting. The SI parameters, i.e., surface roughness average and micro-hardness are selected as the quality targets. An optimal parameter combination of the turning operation is obtained using grey relational analysis. By analysing the grey relational grade matrix, the degree of influence for each controllable process factor onto individual quality targets can be found. The feed rate is identified to have the most influence on the roughness average and also on the micro-hardness. Further, the analysis of variance (ANOVA) is also applied to identify the most significant factor; the feed rate is the most significant controlled factors for affecting the SI in the turning operations according to the weighted sum grade of the surface roughness average and micro-hardness.

Investigation on the effect of Machining Parameters on the Corner Radius in Pocket Milling

In the present work, an investigation on the effect of machining parameters on the pocket milling of EN 31 steel using solid carbide tool was carried out. Experimentation was done as per Taguchis L9 orthogonal array. Each experiment was conducted under varying levels of three different machining parameters i.e. spindle speed, feed rate, and depth of cut and deviation of corner radius of pocket was measured. Optimal combination of machining parameters and their levels for minimum corner radius deviation of pocket was obtained and significance of the machining parameters was determined using ANOVA. Regression equation was obtained to predict the corner radius deviation for different combinations of machining parameters. This study shows that the Taguchis method is suitable to solve the stated problem with minimum number of trails.

RSM Based Investigations on the Effects of Cutting Parameters on Surface Integrity during Cryogenic Hard Turning of AISI 52100

Abstract Effect of cryogenic hard turning parameters (cutting speed, feed rate, and depth of cut) on surface roughness (Ra) and micro-hardness (µH) that constitute surface integrity (SI) of the machined surface of alloy steel AISI 52100 is investigated. Multilayer hard surface coated (TiN/TiCN/Al2O3/TiN) insert on CNC lathe is used for turning under different cutting parameters settings. RSM based Central composite design (CCD) of experiment is used to collect data for Ra and µH. Validity of assumptions related to the collected data is checked through several diagnostic tests. The analysis of variance (ANOVA) is used to determine main and interaction effects. Relationship between the variables is established using quadratic regression model. Both Ra and µH are influenced principally by the cutting speed and the feed rate. Model equations are found to predict accurate values of Ra and µH. Finally, desirability function approach for multiple response optimization is used to produce optimum SI.

Investigations on the Effect of CNC Dry Hard Turning Process Parameters on Surface Integrity: A Multi-performance Characteristics Optimization

Abstract The cutting parameters such as the cutting speed, the feed rate, the depth of cut, etc. are expected to affect the two constituents of surface integrity (SI), i.e., surface roughness and micro-hardness. An attempt has been made in this paper to investigate the effect of the CNC hard turning parameters on the surface roughness average (Ra) and the micro-hardness (μh) of AISI 52100 hard steel under dry cutting conditions. Nine experimental runs based on an orthogonal array of the Taguchi method were performed and grey relational analysis method was subsequently applied to determine an optimal cutting parameter setting. The feed rate was found to be the most influential factor for both the Ra and the μh. Further, the results of the analysis of variance (ANOVA) revealed that the cutting speed is the most significant controlled factor for affecting the SI in the turning operation according to the weighted sum grade of the surface roughness average and micro-hardness.