Modelling of cutting forces in ball-end milling with tool–surface inclination: Part I: Predictive force model and experimental validation
TL;DR: In this paper, the effect of tool-surface inclination on cutting forces in ball-end milling was investigated. But the results were limited to a three-axis CNC equipped with a Kistler dynamometer.
About: This article is published in Journal of Materials Processing Technology.The article was published on 2007-07-06. It has received 105 citations till now. The article focuses on the topics: Hobbing & Chip formation.
Citations
More filters
TL;DR: In this article, the state-of-the-art in predictive performance models for machining operations is presented, and a critical assessment of the relevant modelling techniques and their applicability and/or limitations for the prediction of the complex machining operation performed in industry.
622 citations
TL;DR: In this paper, the authors examined the tool life and wear mechanism when machining Inconel 718 with a physical vapor deposition (PVD)-coated carbide tool and varying the cutting parameters.
94 citations
TL;DR: In this paper, the authors present a mechanics model that predicts the cutting forces in feed ( x ), normal ( y ) and axial ( z ) directions by modeling the chip thickness distribution, and cutting and indentation mechanics.
Abstract: Simulation of multi-axis ball-end milling of dies, molds and aerospace parts with free-form surfaces is highly desirable in order to optimize the machining processes in virtual environment ahead of costly trials. This paper presents a mechanics model that predicts the cutting forces in feed ( x ), normal ( y ) and axial ( z ) directions by modeling the chip thickness distribution, and cutting and indentation mechanics. The shearing forces are based on commonly known cutting mechanics models. The indentation of the cutting edge into the work material is modeled analytically by considering elasto-plastic deformation of the work material pressed by a rigid cutting tool edge with a positive or negative rake angle. The distribution of chip thickness and geometry of indentation zone are evaluated by considering five-axis motion of the tool along the toolpath. The proposed model has been experimentally validated in plunge indentation, as well as in three and five-axis ball-end milling of free-form surfaces. The prediction of axial ( z ) cutting forces is shown to be improved significantly when the proposed indentation model is integrated into the mechanics of ball-end milling.
91 citations
Cites background or methods from "Modelling of cutting forces in ball..."
...In one study, Zeroudi et al. [3] extended the thermo-mechanical oblique cutting model of Fontaine [20] to ball-end milling of sculptured surface....
[...]
...[20] modeled inclined surface ball-end milling forces utilizing the thermomechanical properties of the work material with tool run-out effect....
[...]
...Fontaine et al. [20] modeled inclined surface ball-end milling forces utilizing the thermomechanical properties of the work material with tool run-out effect....
[...]
...[3] extended the thermo-mechanical oblique cutting model of Fontaine [20] to ball-end milling of sculptured surface....
[...]
TL;DR: In this article, a tool motion analysis is used to predict the cutting forces in 5-axis milling processes with radial cutter runout, and the results reveal that the developed method can predict the cutter forces with high accuracy and has the ability to be used in simulations and optimizations of five-axis machining.
Abstract: Radial cutter runout is a common issue in milling processes and has a direct effect on milling stability due to variations of resulting chip load and forces. This paper presents a new method to effectively model and predict the instantaneous cutting forces in 5-axis milling processes with radial cutter runout based on tool motion analysis. First, the undeformed chip thickness model taking runout effect into account is established under continuous change of cutter axis orientation by means of the sweep traces of cutter edges. Second, the engaged cutting edge is determined and cutting coefficients are subsequently calibrated. Finally, the method of identifying runout parameters from the measured cutting forces is proposed, and mechanistic method is then applied to predict the cutting force. Since this method is completely based on the relative motion analysis of tool-part, it can reduce the prediction errors of cutting forces effectively and is suitable for generic rotation cutters. Several validation examples are given under different cutting conditions to prove its effectiveness and accuracy. The results reveal that the developed method can predict the cutter forces with a high accuracy and has the ability to be used in simulations and optimizations of five-axis machining.
71 citations
TL;DR: In this article, an approach to predict cutting force in 3-axis ball end milling of sculptured surface with Z-level contouring tool path is presented. But the approach is not suitable for the case of small steady-state cutting.
Abstract: This paper presents an approach to predict cutting force in 3-axis ball end milling of sculptured surface with Z-level contouring tool path. The variable feed turning angle is proposed to denote the angular position of feed direction within tool axis perpendicular plane. In order to precisely describe the variation of feed turning angle and cutter engagement, the whole process of sculptured surface milling is discretized at intervals of feed per tooth along tool path. Each segmented process is considered as a small steady-state cutting. For each segmented cutting, the feed turning angle is determined according to the position of its start/end points, and the cutter engagement is obtained using a new efficient Z-map method. Both the chip thickness model and cutting force model for steady-state machining are improved for involving the effect of varying feed turning angle and cutter engagement in sculptured surface machining. In validation experiment, a practical 3-axis ball end milling of sculptured surface with Z-level contouring tool path is operated. Comparisons of the predicted cutting forces and the measurements show the reliability of the proposed approach.
69 citations
References
More filters
Book•
15 Mar 1960
TL;DR: In this paper, the authors describe typical cutting operations, including: Elastic Behaviour Plastic Behaviour Fracture Dynamometry Shear Strain in Cutting Shear Stress in Cutting Friction Wear and Tool Life Cutting Temperatures Cutting Fields Tool Materials Work Material Considerations Complex Tools Surface Integrity Chip Control Optimisation Modeling of Chip Formation Precision Engineering Unusual Applications of the Metal Cutting Process
Abstract: Table of Contents Preface Symbols Introduction Typical Cutting Operations Mechanics of Steady State Elastic Behaviour Plastic Behaviour Fracture Dynamometry Shear Strain in Cutting Shear Stress in Cutting Friction Wear and Tool Life Cutting Temperatures Cutting Fields Tool Materials Work Material Considerations Complex Tools Surface Integrity Chip Control Optimisation Modeling of Chip Formation Precision Engineering Unusual Applications of the Metal Cutting Process
2,229 citations
TL;DR: In this paper, the fundamental cutting parameters, the yield shear stress, average friction coefficient on the rake face and shear angle are measured from a set of orthogonal cutting tests at various cutting speeds and feeds.
Abstract: The mechanics of cutting with helical ball-end mills are presented. The fundamental cutting parameters, the yield shear stress, average friction coefficient on the rake face and shear angle are measured from a set of orthogonal cutting tests at various cutting speeds and feeds. The cutting forces are separated into edge or ploughing forces and shearing forces. The helical flutes are divided into small differential oblique cutting edge segments. The orthogonal cutting parameters are carried to oblique milling edge geometry using the classical oblique transformation method, where the chip flow angle is assumed to be equal to the local helix angle. The cutting force distribution on the helical ball-end mill flutes is accurately predicted by the proposed method, and the model is validated experimentally and statistically by conducting more than 60 ball-end milling experiments.
383 citations
TL;DR: In this article, a generalized mathematical model of most helical end mills used in the industry is presented, where the end mill geometry is modeled by helical flutes wrapped around a parametric envelope.
Abstract: A variety of helical end mill geometry is used in the industry. Helical cylindrical, helical ball, taper helical ball, bull nosed and special purpose end mills are widely used in aerospace, automotive and die machining industry. While the geometry of each cutter may be different, the mechanics and dynamics of the milling process at each cutting edge point are common. This paper presents a generalized mathematical model of most helical end mills used in the industry. The end mill geometry is modeled by helical flutes wrapped around a parametric envelope. The coordinates of a cutting edge point along the parametric helical flute are mathematically expressed. The chip thickness at each cutting point is evaluated by using the true kinematics of milling including the structural vibrations of both cutter and workpiece. By integrating the process along each cutting edge, which is in contact with the workpiece, the cutting forces, vibrations, dimensional surface finish and chatter stability lobes for an arbitrary end mill can be predicted. The predicted and measured cutting forces, surface roughness and stability lobes for ball, helical tapered ball, and bull nosed end mills are provided to illustrate the viability of the proposed generalized end mill analysis.
345 citations
TL;DR: The concept of ploughing force on the extreme cutting edge allows the development of a more complete force diagram which separates the ploughding force from the chip-tool interface force as discussed by the authors.
Abstract: Revelation of the significance of “ploughing” in the metal-cutting process, which occurs because of the finite sharpness of the cutting edge, leads to a better understanding of the mechanics of the metal-cutting process. The concept of the ploughing force on the extreme cutting edge allows the development of a more complete force diagram which separates the ploughing force from the chip-tool interface force. Components of this more detailed force diagram have been verified experimentally. In terms of the new force diagram the real value of the coefficient of friction on the chip-tool interface has been found and the paradox of variation of the coefficient of friction with variation of rake angle explained. The paper also contributes to a better understanding of such events as the effect of cutting velocity upon tool forces, built-up edge, chip curling, and residual stresses in the work surfaces.
275 citations
TL;DR: In this paper, the authors developed a model to predict the instantaneous cutting force of a ball-end mill with plane rake faces based on the analysis of the cutting geometry of a small cutting edge element.
Abstract: Due to the development of CNC machining centers and automatic programming software, the ball-end milling have become the most widely used machining process for sculptured surfaces. In this study, the ball-end milling process has been analysed, and its cutting force model has been developed to predict the instantaneous cutting force on given machining conditions. The development of the model is based on the analysis of cutting geometry of the ball-end mill with plane rake faces. A cutting edge of the ball-end mill was considered as a series of infinitesimal elements, and the geometry of a cutting edge element was analysed to calculate the necessary parameters for its oblique cutting process assuming that each cutting edge was straight. The oblique cutting process in the small cutting edge element has been analysed as an orthogonal cutting process in the plane containing the cutting velocity and chip flow vectors. And with the orthogonal cutting data obtained from end turning tests on thin-walled tubes over wide range of cutting and tooling conditions, the cutting forces of ball-end milling could be predicted using the model. The predicted cutting forces have shown a fairly good agreement with test results in various machining modes.
202 citations