Identification of the Cutting Forces Coefficients via Milling Process Simulation

Author(s):  
Sergey A. Voronov ◽  
Igor A. Kiselev ◽  
Maxim G. Yakovlev

The paper is devoted to the description of a new technique (numerical and experimental) identification of the dependences between cutting forces and instantaneous chip thickness. It is required to measure only the cutting forces versus cutting conditions. Experimentally, for the given pair the processed material – the tool, coefficients of the cutting forces model are calculated by means of the optimization method (Nelder-Mead algorithm). The mathematical model of the milling process developed by authors on each step of the Nelder-Mead method is used for the process numerical simulation under given coefficients of the cutting force model. The elaborated numerical modeling algorithm allows investigating the dynamics and the kinematics of the milling process. The dynamic model of the tool, the algorithm of geometrical modeling of the instantaneous chip thickness, the finite element model of the detail are embedded into the whole model of the milling process.

Author(s):  
Xuewei Zhang ◽  
Tianbiao Yu ◽  
Wanshan Wang

An accurate prediction of cutting forces in the micro end milling, which is affected by many factors, is the basis for increasing the machining productivity and selecting optimal cutting parameters. This paper develops a dynamic cutting force model in the micro end milling taking into account tool vibrations and run-out. The influence of tool run-out is integrated with the trochoidal trajectory of tooth and the size effect of cutting edge radius into the static undeformed chip thickness. Meanwhile, the real-time tool vibrations are obtained from differential motion equations with the measured modal parameters, in which the process damping effect is superposed as feedback on the undeformed chip thickness. The proposed dynamic cutting force model has been experimentally validated in the micro end milling process of the Al6061 workpiece. The tool run-out parameters and cutting forces coefficients can be identified on the basis of the measured cutting forces. Compared with the traditional model without tool vibrations and run-out, the predicted and measured cutting forces in the micro end milling process show closer agreement when considering tool vibrations and run-out.


2011 ◽  
Vol 188 ◽  
pp. 404-409 ◽  
Author(s):  
Xue Yan ◽  
Hua Tao ◽  
D.H. Zhang ◽  
B.H. Wu

A developed method to predict the cutting forces in end milling of generalized corners is proposed in this paper. The cornering milling process is divided into a series of cutting segments with different cutting states. The mathematical model of the geometric relationship between cutter and the corner profile is established for each segment. Cutting forces is predicted by introducing the classical cutting force model. The computational results of cutting forces are in good agreement with experimental data.


2000 ◽  
Vol 123 (1) ◽  
pp. 23-29 ◽  
Author(s):  
Hsi-Yung Feng ◽  
Ning Su

This paper presents an improved mechanistic cutting force model for the ball-end milling process. The objective is to accurately model the cutting forces for nonhorizontal and cross-feed cutter movements in 3D finishing ball-end milling. Main features of the model include: (1) a robust cut geometry identification method to establish the complicated engaged area on the cutter; (2) a generalized algorithm to determine the undeformed chip thickness for each engaged cutting edge element; and (3) a comprehensive empirical chip-force relationship to characterize nonhorizontal cutting mechanics. Experimental results have shown that the present model gives excellent predictions of cutting forces in 3D ball-end milling.


Author(s):  
Caixu Yue ◽  
Xianli Liu ◽  
Yunpeng Ding ◽  
Steven Y Liang

Tool deflection induced by cutting force could result in dimensional inaccuracies or profile error in corner milling process. Error compensation has been proved to be an effective method to get accuracy component in milling process. This article presents a methodology to compensate profile errors by modifying tool path. The compensation effect strongly depends on accuracy of the cutting force model used. The mathematical expression of chip thickness is proposed based on the true track of cutting edge for corner milling process, which considers the effect of tool deflection. The deflection of tool is calculated by finite element method. Then, an off-line compensation algorithm for corner profile error is developed. Following the theoretical analysis, the effect of the error compensation algorithm is verified by experimental study. The outcome provides useful comprehension about selection of process conditions for corner milling process.


2016 ◽  
Vol 693 ◽  
pp. 843-849
Author(s):  
An Hai Li ◽  
Jun Zhao ◽  
He Lin Pan ◽  
Zhao Chao Gong

In order to acquire high machining quality and minimum machining time, cutting forces are usually modeled to understand the milling process, simulate or predict cutting forces, and optimize the machining parameters. In this paper, side milling tests were conducted on superalloy Inconel 718 with a solid carbide end mill, and the cutting forces vs. cutting time were measured. The average cutting forces were extracted from the measured instantaneous cutting forces under different feed rates of experiments, and the components of the shear forces and edge forces were determined by using the linear regression of the experimental data. The cutting force coefficients, including shear force coefficients and edge force coefficients, were identified. In addition, the algorithms of the mathematical model were implemented in Matlab. The predicted cutting forces were in good agreement with the experimentally measured forces, and the validation of the cutting force model was demonstrated.


Author(s):  
Han Ul Lee ◽  
Dong-Woo Cho

In this paper, a milling process simulation system was constructed and ME Z-map (Moving Edge node Z-map) model was developed to elevate the performance of this system. The milling process simulation system computes the cutting configuration and then the cutting forces are predicted using these calculated configurations. In this system, an improved cutting force model which is independent of cutting conditions is used to more precisely predict the cutting forces. In the process, the ME Z-map model was used for more accurate computing of cutting configuration. Due to the edge node, ME Z-map model produces more accurate cutting configuration than the conventional Z-map models even with five to ten times larger grid size, which reduces the computing time dramatically. The superiority of the ME Z-map model was confirmed through comparison with the conventional Z-map.


2013 ◽  
Vol 554-557 ◽  
pp. 2054-2061 ◽  
Author(s):  
Hassan Zamani ◽  
Jan Patrick Hermani ◽  
Bernhard Sonderegger ◽  
Christof Sommitsch

During machining of hard materials, one approach to reduce tool wear is using a laser beam to preheat the material in front of the cutting zone. In this study, a new concept of laser-assisted milling with spindle and tool integrated laser beam guiding has been tested. The laser beam is located at the cutting edge and moving synchronously with the cutter. In experiment, a reduction in the resulting process cutting forces and tool wear has been observed in comparison to milling without laser. A three-dimensional finite element model in DEFORM 3D was developed to predict the cutting forces in the milling process with and without an additional laser heat source, based on a Johnson-Cook-type material constitutive model adapted for high strains and strain rates. Both in experiment and simulation, the deformation behavior of a Ti-6Al-4V workpiece has been investigated. The comparison of the resulting cutting forces showed very good agreement. Thus the new model has great potential to further optimize laser assisted machining processes.


2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Haoqiang Zhang ◽  
Xibin Wang ◽  
Siqin Pang

In microdrilling, because of lower feed, the microdrill cutting edge radius is comparable to the chip thickness. The cutting edges therefore should be regarded as rounded edges, which results in a more complex cutting mechanism. Because of this, the macrodrilling thrust modeling is not suitable for microdrilling. In this paper, a mathematical modeling to predict microdrilling thrust is developed, and the geometric characteristics of microdrill were considered in force models. The thrust is modeled in three parts: major cutting edges, secondary cutting edge, and indentation zone. Based on slip-line field theory, the major cutting edges and secondary cutting edge are divided into elements, and the elemental forces are determined by an oblique cutting model and an orthogonal model, respectively. The thrust modeling of the major cutting edges and second cutting edge includes two different kinds of processes: shearing and ploughing. The indentation zone is modeled as a rigid wedge. The force model is verified by comparing the predicted forces and the measured cutting forces.


2012 ◽  
Vol 504-506 ◽  
pp. 1269-1274 ◽  
Author(s):  
François Ducobu ◽  
Edouard Rivière-Lorphèvre ◽  
Enrico Filippi

Micro-milling with a cutting tool is a manufacturing technique that allows production of parts ranging from several millimeters to several micrometers. The technique is based on a downscaling of macroscopic milling process. Micro-milling is one of the most effective process to produce complex three-dimensional micro-parts, including sharp edges and with a good surface quality. Reducing the dimensions of the cutter and the cutting conditions requires taking into account physical phenomena that can be neglected in macro-milling. These phenomena include a size effect (nonlinear rising of specific cutting force when chip thickness decreases), the minimum chip thickness (under a given dimension, no chip can be machined) and the heterogeneity of the material (the size of the grains composing the material is significant as compared to the dimension of the chip). The aim of this paper is to introduce some phenomena, appearing in micromilling, in the mechanistic dynamic simulation software ‘dystamill’ developed for macro-milling. The software is able to simulate the cutting forces, the dynamic behavior of the tool and the workpiece and the kinematic surface finish in 2D1/2 milling operation (slotting, face milling, shoulder milling,…). It can be used to predict chatter-free cutting condition for example. The mechanistic model of the cutting forces is deduced from the local FEM simulation of orthogonal cutting. This FEM model uses the commercial software ABAQUS and is able to simulate chip formation and cutting forces in an orthogonal cutting test. This model is able to reproduce physical phenomena in macro cutting conditions (including segmented chip) as well as specific phenomena in micro cutting conditions (minimum chip thickness and size effect). The minimum chip thickness is also taken into account by the global model. The results of simulation for the machining of titanium alloy Ti6Al4V under macro and micro milling condition with the mechanistic model are presented discussed. This approach connects together local machining simulation and global models.


1994 ◽  
Vol 116 (1) ◽  
pp. 17-25 ◽  
Author(s):  
J.-J. Junz Wang ◽  
S. Y. Liang ◽  
W. J. Book

This paper presents the establishment of a closed form expression for the dynamic forces as explicit functions of cutting parameters and tool/workpiece geometry in milling processes. Based on the existing local cutting force model, the generation of total cutting forces is formulated as the angular domain convolution of three cutting process component functions, namely the elementary cutting function, the chip width density function, and the tooth sequence function. The elemental cutting force function is related to the chip formation process in an elemental cutting area and it is characterized by the chip thickness variation, and radial cutting configuration. The chip width density function defines the chip width per unit cutter rotation along a cutter flute within the range of axial depth of cut. The tooth sequence function represents the spacing between flutes as well as their cutting sequence as the cutter rotates. The analysis of cutting forces is extended into the Fourier domain by taking the frequency multiplication of the transforms of the three component functions. Fourier series coefficients of the cutting forces are shown to be explicit algebraic functions of various tool parameters and cutting conditions. Numerical simulation results are presented in the frequency domain to illustrate the effects of various process parameters. A series of end milling experiments are performed and their results discussed to validate the analytical model.


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