The effectiveness of the finished component in turning process is highly reliant on the parameters related to the workpiece and cutting tool. This paper aims to assess the impact of machining ...parameters on tangential, radial and axial forces while turning AISI 201 stainless steel using cemented carbide tool insert. Process parameters such as spindle speed, feed, depth of cut, and workpiece diameter were used. Four-factors and four-level L16 Taguchi Design of Experiments were employed. In addition, the Analysis of Variance (ANOVA) was used to explore the effects of process parameters and their impact on interactions. After that, an attempt was made to generate prediction models by establishing a regression equation for the cutting forces. Predicted and measured values were plotted in the graphs and comparisons were shown. Finally, the interaction effects between the cutting forces and machining parameters were analyzed as well.
Rule-of-thumb based design for cutting tools and machining settings in face-hobbing of bevel gears result in cutting tool failures and quality issues. Lack of a virtual machining environment, to ...efficiently obtain the instantaneous un-deformed chip geometry and predict cutting forces in face-hobbing, causes undesirable production costs in industries. In the present paper, semi-analytical representation of the projection of the un-deformed chip on the rake face of the cutting blades is presented. The proposed approach is drastically fast and more accurate in comparison with numerical methods and can be implemented in a virtual gear machining environment. The cutting system intricate geometry, multi-axis machine tool kinematic chains and the variant cutting velocity along the cutting edge are taken into consideration to obtain the chip geometry efficiently. Then, cutting forces are predicted during face-hobbing by implementing oblique cutting theory using the derived chip geometry and converting face-hobbing into oblique cutting. The proposed methods are applied on two case studies of face-hobbing of bevel gears, and the chip geometry is derived and the cutting forces are predicted.
•Semi-analytical representation of the chip geometry in face-hobbing is presented.•The method is computationally efficient and more accurate than numerical methods.•Cutting forces in face-hobbing are predicted.•Regions where are more prone to be worn out along the cutting edge are predicted.
In any machining process, it is important to select the appropriate machining parameters to facilitate the better Material removal rate (MRR). The generation of prediction equations are of utmost ...importance in the optimization of the machining parameters. In this paper, an artificial neural network (ANN) assisted improved prediction model for the MRR of Glass fiber reinforced plastic composites (GFRP) turned components is built using Multiple regression analysis (MRA). Using the process parameters namely spindle speed, feed and depth of cut, the turning of the GFRP composites was carried out on a conventional lathe using single point HSS cutting tool. By employing the Taguchi's L16 array (3 Level), the experiments were conducted and the MRA was carried out for the prediction of Material removal rate (MRR). The MRA predicted values were found to be less accurate for the test data of MRR. In order to overcome this problem, an experimentally validated radial basis ANN was used to predict the MRR values for L343 array (7 level). Further using this L343 array, MRA was again conducted to develop the expression for MRR. This expression for MRR yielded a drastically improved result. The reason for this can be attributed to the use of a higher input level Taguchi's design, which was made possible by adopting the radial basis ANN.
This reprint aims to disseminate the latest research achievements, findings, and ideas in the robotics field, with particular focus on the Italian scenario. It covers a range of topics related to the ...theory, design, practice, and applications of robots, such as robot design and kinematics, dynamics of robots and multi-body systems, linkages and manipulators, control of robotic systems, trajectory planning and optimization, innovative robots and applications, industrial robotics, collaborative robotics, medical robotics, assistive robotics, and service robotics. The reprints contributions include (but are not limited to) revised and substantially extended versions of selected papers that were presented at the 2nd International Conference of IFToMM, Italy (IFIT 2018).
The authors analyzed the force and stress values in the simplified cutting model and compared the results with the literature. For the study a 2D model was created in DEFORM 2D finite element ...software, using the temperature depended multilinear flow stress material model. The model was compiled according to the literatures. In this analysis were the effects of relief angel, tool angle, tool radius, depth of cut, and the cutting velocity examined. The values of forces, strain, temperature, stress and shear plane angle were examined at different values of geometry and machining parameters. For these examinations were used 28 parameter combinations. As a result of the study, the results for forces are similar to the results of examined literature at every parameter. The force results were checked on a simple tool geometry.
This article is concerned with the cutting forces and surface integrity in high-speed side milling of Ti-6Al-4V titanium alloy. The experiments were conducted with coated carbide cutting tools under ...dry cutting conditions. The effects of cutting parameters on the cutting forces, tool wear and surface integrity (including surface roughness, microhardness and microstructure beneath the machined surface) were investigated. The velocity effects are focused on in the present study. The experimental results show that the cutting forces in three directions increase with cutting speed, feed per tooth and depth of cut (DoC). The widths of flank wear VB increases rapidly with the increasing cutting speed. The surface roughness initially decreases and presents a minimum value at the cutting speed 200 m/min, and then increases with the cutting speed. The microstructure beneath the machined surfaces had minimal or no obvious plastic deformation under the present milling conditions. Work hardening leads to an increment in micro-hardness on the top surface. Furthermore, the hardness of machined surface decreases with the increase of cutting speed and feed per tooth due to thermal softening effects. The results indicated that the cutting speed 200 m/min could be considered as a critical value at which both relatively low cutting forces and improved surface quality can be obtained.
The abrasive wear behaviour and fatigue life of many components in mechanical engineering depend on their surface stress states. Compressive surface stresses hinder ductile or brittle crack formation ...as well as crack propagation into the bulk material and therefore increase the lifetime of dynamically or abrasively loaded parts. The thermo-mechanical loads acting on the workpiece surface during metal cutting determine the stress state after processing. Under the high strain rates of cutting, the underlying mechanisms include the accumulation of stress fields around dislocations resulting from plastic deformation as well as thermal expansion and shrinking phenomena associated with the dissipation of mechanical energy. Until now, the underlying thermodynamics of residual stress formation in metal cutting are hardly understood quantitatively, which explains the current dominance of empirical-iterative design procedures of cutting processes regarding residual stresses.
In this work, the derivation and experimental validation of a thermodynamics based finite element model for the energy transformations during residual stress formation are presented. For the first time, the residual surface stress state is correlated with the mechanical and dissipative thermal energies, which are transformed during processing. It is shown how each residual stress component relates to these energy transformations. These findings are applied to formulate characteristic process signatures, which may be used to describe the formation of residual stresses in other manufacturing technologies as well.
The proposed work includes orthogonal cutting tests on quenched and tempered AISI 4140, subsequent determination of the residual stress states using a diffractometric measurement technique, the analytical description of the energy transformations during residual stress formation as well as its implementation into a finite element process model.
•A process signature (PS) for residual surface stresses in metal cutting is compiled.•Residual stresses are measured in experiments by X-ray diffraction.•Mechanical and thermal energy input in surface are simulated by FE-model.•Correlation of residual stress distribution with energies constitutes PS.•Characteristic relation between residual stresses and energies is explained.
In this study, the effects of cutting edge geometry, workpiece hardness, feed rate and cutting speed on surface roughness and resultant forces in the finish hard turning of AISI H13 steel were ...experimentally investigated. Cubic boron nitrite inserts with two distinct edge preparations and through-hardened AISI H13 steel bars were used. Four-factor (hardness, edge geometry, feed rate and cutting speed) two-level fractional experiments were conducted and statistical analysis of variance was performed. During hard turning experiments, three components of tool forces and roughness of the machined surface were measured. This study shows that the effects of workpiece hardness, cutting edge geometry, feed rate and cutting speed on surface roughness are statistically significant. The effects of two-factor interactions of the edge geometry and the workpiece hardness, the edge geometry and the feed rate, and the cutting speed and feed rate also appeared to be important. Especially honed edge geometry and lower workpiece surface hardness resulted in better surface roughness. Cutting-edge geometry, workpiece hardness and cutting speed are found to be affecting force components. The lower workpiece surface hardness and honed edge geometry resulted in lower tangential and radial forces.
For the critical aero-engine parts it’s important to understand influence of cutting tools, cutting parameters, tool ware etc. on near surface condition which highly affect fatigue strength and at ...the same part life-time. New material implemented for the latest designs of aero-engines parts generate challenges for machining processes to fulfil strict requirements of aviation standards. Finish machining is the most important stage of process influencing fatigue strength. cBN tool are often used for final stage of machining. The objective of this study was analysis of cutting mechanics during finish turning of modern nickel-cobalt based alloy with cBN insert. Observations of cutting tool wear and cutting parameters influence on the components of cutting force, surface roughness and residual stress are presented in this paper.
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