Integrated Simulation of Machine Tool and Process Interaction for Turning (original) (raw)
Related papers
Modeling of Cutting Force Distribution on Tool Edge in Turning Process
Procedia Manufacturing, 2015
Machining process models can be used to predict cutting force/power and further optimize the process parameters. In this work, a mechanistic cutting force model for turning processes is developed. In order to accurately predict cutting forces, the cutting tool edge is discretized and an approach for calculating the chip load corresponding to each discretized edge segment is developed. Approach for calculating effective tool angles is also developed considering effects of the tool corner radius and the change of feed direction. By using the yield shear stress of the work material, the friction angle between work and tool material, the chip load and the effective tool angles for each tool edge segment, the distributions of the turning forces and force intensity along the tool edge can be predicted. Turning cases of straight turning, contour turning, taper turning and facing are tested and the model outputs include the distributions of the instantaneous effective tool angles, chip load, cutting force coefficients and force intensity. Test results for straight turning and contour turning operations are analyzed to demonstrate the model capability. The distributions of force and force intensity on tool edge provide useful information for prediction of turning forces/power and potential further prediction of tool wear/life.
3D FEA Modeling of Hard Turning
Journal of Manufacturing Science and Engineering-transactions of The Asme, 2002
A practical explicit 3D finite element analysis model has been developed and implemented to analyze turning hardened AISI 52100 steels using a PCBN cutting tool. The finite element analysis incorporated the thermo-elastic-plastic properties of the work material in machining. An improved friction model has been proposed to characterize tool-chip interaction with the friction coefficient and shear flow stresses determined by force calibration and material tests, respectively. A geometric model has been established to simulate a 3D turning. FEA Model predictions have reasonable accuracy for chip geometry, forces, residual stresses, and cutting temperatures. FEA model sensitivity analysis indicates that the prediction is consistent using a suitable magnitude of material failure strain for chip separation, the simulation gives reasonable results using the experimentally determined material properties, the proposed friction model is valid and the sticking region on the tool-chip interface is a dominant factor of model predictions.
Analytical Modeling of Turn-milling Process Geometry, Kinematics and Mechanics
International Journal of Machine Tools and Manufacture, 2014
This paper presents an analytical approach for modeling of turn-milling which is a promising cutting process combining two conventional machining operations; turning and milling. This relatively new technology could be an alternative to turning for improved productivity in many applications but especially in cases involving hard-to-machine material or large work diameter. Intermittent nature of the process reduces forces on the workpiece, cutting temperatures and thus tool wear, and helps breaking of chips. The objective of this study is to develop a process model for turn-milling operations. In this article, for the first time, uncut chip geometry and tool-work engagement limits are defined for orthogonal, tangential and co-axial turn-milling operations. A novel analytical turn-milling force model is also developed and verified by experiments. Furthermore, matters related to machined part quality in turnmilling such as cusp height, circularity and circumferential surface roughness are defined and analytical expressions are derived. Proposed models show a good agreement with the experimental data where the error in force calculations is less than 10% for different cutting parameters and less than 3% in machined part quality analysis.
A 3D Turning Model for the Interpretation of Machining Stability and Chatter
Nonlinear Science and Complexity - Proceedings of the Conference, 2007
Turning dynamics is investigated using a 3D model that allows for simultaneous workpiece-tool deflections in response to the exertion of nonlinear regenerative force. The workpiece is modeled as a system of three rotors connected by a flexible shaft. Such a configuration enables the motion of the workpiece relative to the tool and tool motion relative to the machining surface to be three-dimensionally established as functions of spindle speed, instantaneous depth-of-cut, material removal rate and whirling. The model is explored along with its 1D counterpart, which considers only tool motions and disregards workpiece vibrations. Different stages of stability for the workpiece and the tool subject to the same cutting conditions are studied. : 05.45.-a, 46.32.+x
2015
In this paper a new frictional model of cutting process [1] developed to gain better insight into the mechanics of frictional chatter is presented. The model takes into account the forces acting on the tool face as well as on the tool flank. Nonlinear dynamic behaviour is presented using bifurcation diagrams for nominal uncut chip thickness (feed rate) as the bifurcation parameters. The influence of the depth of cut for different tool stiffnesses have been investigated. Finally, the influence of the tool flank forces on the system dynamics is studied. c © 2015 The Authors. Published by Elsevier B.V. Peer-review under responsibility of The International Scientific Committee of the “15th Conference on Modelling of Machining Operations”.
Use of finite element structural models in analyzing machine tool chatter
Finite Elements in Analysis and Design, 2002
It is widely accepted and well-documented that regenerative machine tool chatter is due to system instability. It is also well-known that machining system stability depends on both structural parameters and cutting process parameters. This paper focuses on the use of structural ÿnite element (FE) models in the stability analysis of turning operations. The method presented allows for inclusion of both cutting tool and workpiece exibility in the analysis. A structural model representing the machine tool system is created using the commercial FE code, ANSYS. This structural model can include practically any degree of detail desired. The structural model is then imported into a stand-alone FORTRAN program, which incorporates a cutting process model, and calculates the lobed borderline of stability. Numerical examples are provided.
On the turning modeling and simulation: 2D and 3D FEM approaches
Mechanics & Industry, 2014
For qualitative prediction of chip morphology and quantitative prediction of burr size, 2D and 3D finite element (FE) based turning models have been developed in this paper. Coupled temperaturedisplacement machining simulations exploiting the capabilities of Abaqus r with a particular industrial turning insert and a newly proposed geometrical version of this insert have been performed. Limitations of 2D models in defining the chip morphologies and surface topologies have been discussed. The phenomenological findings on the Poisson burr (Side burr) formation using 3D cutting models have been highlighted. Bespoke geometry of the turning insert has been found helpful in reducing the Poisson burr formation, as it reduces the contact pressures at the edges of tool rake face-workpiece interface. Lower contact pressures serve to decrease the material flow towards workpiece edges (out of plane deformation). In contrast, higher contact pressures at tool rake face-workpiece interface lead to more material flow towards workpiece edges resulting in longer burr. Simulation results of chip morphologies and cutting forces for turning an aluminum alloy A2024-T351 have been compared with the experimental ones. Finally, it has been concluded that the newly proposed geometry of the insert not only decreases the burr but also helpful in lessening the magnitude of tool-workpiece initial impact.
Mechanistic modelling of the milling process using complex tool geometry
The International Journal of Advanced Manufacturing Technology, 2005
Mechanistic models of the milling process must calculate the chip geometry and the cutter edge contact length in order to predict milling forces accurately. This task becomes increasingly difficult for the machining of three dimensional parts using complex tool geometry, such as bull nose cutters. In this paper, a mechanistic model of the milling process based on an adaptive and local depth buffer of the computer graphics card is compared to a traditional simulation method. Results are compared using a 3-axis wedge shaped cut -a tool path with a known chip geometry in order to accommodate the traditional method. Effects of cutter nose radius on the cutting and edge forces are considered. It is verified that there is little difference (1.4% at most) in the predicted force values of the two methods, thereby validating the adaptive depth buffer approach. The numerical simulations are also verified using experimental cutting tests of aluminum, and found to agree closely (within 12%).
Modeling and Simulation of a Chip Load Acting on a Single Milling Tool Insert
Strojniški vestnik – Journal of Mechanical Engineering, 2012
The paper presents experimental and numerical study of the end-milling process. The aim of this study is to define the force acting on a single cutting tool insert. It was accomplished by transforming cutting force signals from coordinate system of Kistler dynamometer into milling tool coordinate system.
Micromachines
The present study investigated the performance of three ceramic inserts in terms of the micro-geometry (nose radius and cutting edge type) with the aid of a 3D finite element (FE) model. A set of nine simulation runs was performed according to three levels of cutting speed and feed rate with respect to a predefined depth of cut and tool nose radius. The yielded results were compared to the experimental values that were acquired at identical cutting conditions as the simulated ones for verification purposes. Consequently, two more sets of nine simulations each were carried out so that a total of 27 turning simulation runs would adduce. The two extra sets corresponded to the same cutting conditions, but to different cutting tools (with varied nose radius). Moreover, a prediction model was established based on statistical methodologies such as the response surface methodology (RSM) and the analysis of variance (ANOVA), further investigating the relationship between the critical paramet...