Model of the instantaneous undeformed chip thickness in micro-milling based on tooth trajectory

2016 ◽  
Vol 232 (2) ◽  
pp. 226-239 ◽  
Author(s):  
Xiaohong Lu ◽  
Zhenyuan Jia ◽  
Furui Wang ◽  
Guangjun Li ◽  
Likun Si ◽  
...  
Keyword(s):  
Cutting Forces ◽  
Chip Thickness ◽  
Milling Process ◽  
Cutting Edge ◽  
Micro Milling ◽  
Undeformed Chip Thickness ◽  
Single Tooth ◽  
Extended Length ◽  
Manufacturing Errors ◽  
Tooth Cutting

Instantaneous undeformed chip thickness is one of the key parameters in modeling of micro-milling process. Most of the existing instantaneous undeformed chip thickness models in meso-scale cutting process are based on the trochoidal trajectory of the cutting edge, which neglect the influences of cutter installation errors, cutter-holder manufacturing errors, radial runout of the spindle and so forth on the instantaneous undeformed chip thickness. This article investigates the tooth trajectory in micro-milling process. A prediction model of radial runout of cutting edge is built, with consideration of the effects of the extended length of micro-milling cutter and the spindle speed. Considering the effects of cutting-edge trochoidal trajectory, radial runout of cutting edge and the minimum cutting thickness, a novel instantaneous undeformed chip thickness model is proposed, and the phenomenon of single-tooth cutting in micro-milling process is analyzed. Comparisons of cutting forces under different chip thickness models and experimental data indicate that this new model can be used to predict cutting forces.

A Comprehensive Micro-milling Force Model for A Low-stiffness Machining System

2021 ◽  
pp. 1-42
Author(s):  
Da Qu ◽  
Bo Wang ◽  
Yuan Gao ◽  
Huajun Cao
Keyword(s):  
Chip Thickness ◽  
Micro Milling ◽  
Force Model ◽  
Milling Force ◽  
Undeformed Chip Thickness ◽  
Single Tooth ◽  
Good Prediction Accuracy ◽  
Low Stiffness ◽  
Milling Force Model ◽  
Tooth Cutting

Abstract Micro-milling is widely used in various crucial fields with the ability of machining micro- and meso-scaled functional structures on various materials efficiently. However, the micro-milling force model is not comprehensively developed yet when tool feature sizes continually decrease to under two hundred microns in a low-stiffness system. This paper proposes an analytical force model considering the influence of tool radius, size effect, tool runout, tool deflection, and the actual trochoidal trajectories and the interaction of historical tool teeth trajectories (IHTTT). Different micro-milling status are recognized by analyzing the cutting process of different tool teeth. Conditions of single-tooth cutting status are determined by a proposed numerical algorithm, and entry angle and exit angle are analyzed under various cutting conditions for the low-stiffness system. Three micro-milling status, including single-tooth cutting status, are distinguished based on the instantaneous undeformed chip thickness resulting in three types of material removal mechanisms in predicting micro-milling force components. Discontinuous change rates of undeformed chip thickness are found in the low-stiffness micro-milling system. The proposed micro-milling force model is then verified through experiments of micro slot milling Elgiloy alloy with a 150-µm-diametrical two-teeth micro-end-mill. The experimental results show a Root-Mean-Square Error (RSME) of 0.092 N in the predicted resultant force, accounting for approximately 5.12% of the measured force, by which the proposed theoretical model is verified to be of good prediction accuracy.

Dynamic Simulation of the Micro-Milling Process Including Minimum Chip Thickness and Size Effect

2012 ◽  
Vol 504-506 ◽  
pp. 1269-1274 ◽  
Author(s):  
François Ducobu ◽  
Edouard Rivière-Lorphèvre ◽  
Enrico Filippi
Keyword(s):  
Size Effect ◽  
Cutting Forces ◽  
Mechanistic Model ◽  
Orthogonal Cutting ◽  
Chip Thickness ◽  
Milling Process ◽  
Cutting Conditions ◽  
Micro Milling ◽  
Minimum Chip Thickness ◽  
Physical Phenomena

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.

Generalized Modeling of Milling Mechanics and Dynamics: Part I — Helical End Mills

1999 ◽  
Author(s):  
Serafettin Engin ◽  
Yusuf Altintas
Keyword(s):  
Cutting Forces ◽  
Chip Thickness ◽  
Milling Process ◽  
Cutting Edge ◽  
End Mill ◽  
Edge Point ◽  
Stability Lobes ◽  
End Mills ◽  
Helical Flute ◽  
Cutting Point

Abstract Variety of helical end mill geometry is used in 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 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.

Development of Micro Milling Machine and Experimental Study on Meso Scale Milling

2007 ◽  
Author(s):  
Chengfeng Li ◽  
Xinmin Lai ◽  
Hongtao Li ◽  
Linfa Peng ◽  
Jun Ni
Keyword(s):  
Chip Formation ◽  
Cutting Forces ◽  
High Speed ◽  
End Milling ◽  
Three Dimensional ◽  
Chip Thickness ◽  
Cutting Edge ◽  
Micro Milling ◽  
Milling Machine ◽  
Meso Scale

This paper develops a three-axis micro milling machine for manufacturing meso-scale components and products. This machine utilizes high-speed miniature spindle to obtain appropriate cutting velocities, and three precision linear stages with 50 nm feed resolution to supply the relative motion. The PMAC2 controller is used to control three axes simultaneously, and a piezoelectric dynamometer is mounted on the X-Y stages to measure three-dimensional cutting forces for the real-time measurement and feedback. More than 200 cutting experiments of end milling operations are performed on the developed machine. When the machined feature ranges at meso scale, the characteristics and phenomena in milling process will heavily differ from those of conventional scale milling due to the size effects. The critical differences at meso scale arise from the breakdown of the assumptions of negligible edge radius effects. The roundness of cutting edge and the runout of spindle have a crucial impact on the chip formation process and the characteristics of cutting forces. The roundness of cutting edge also induces the existence of the minimum chip thickness and the intermittency of the chip formation at a low feed per tooth.

An Approach to Modeling Cutting Forces in Five-Axis Ball-End Milling of Curved Geometries Based on Tool Motion Analysis

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Guo Dongming ◽  
Ren Fei ◽  
Sun Yuwen
Keyword(s):  
Motion Analysis ◽  
Cutting Forces ◽  
End Milling ◽  
Chip Thickness ◽  
Cutting Edge ◽  
Axis Orientation ◽  
Undeformed Chip Thickness ◽  
Ball End Milling ◽  
Tool Motion ◽  
Five Axis

The prediction of five-axis ball-end milling forces is quite a challenge due to difficulties of determining the underformed chip thickness and engaged cutting edge. To solve these concerns, this paper presents a new mechanistic model of cutting forces based on tool motion analysis. In the model, for undeformed chip thickness determination, an analytical model is first established to describe the sweep surface of cutting edge during the five-axis ball-end milling process of curved geometries. The undeformed chip thickness is then calculated according to the real kinematic trajectory of cutting edges under continuous change of the cutter axis orientation. A Z-map method is used to verify the engaged cutting edge and cutting coefficients are subsequently calibrated. The mechanistic method is applied to predict the cutting force. Validation tests are conducted under different cutter postures and cutting conditions. The comparison between predicted and measured values demonstrates the applicability of the proposed prediction model of cutting forces.

Mechanism of Cutting Force and Surface Generation in Dynamic Milling

1991 ◽  
Vol 113 (2) ◽  
pp. 160-168 ◽  
Author(s):  
D. Montgomery ◽  
Y. Altintas
Keyword(s):  
Cutting Force ◽  
Surface Finish ◽  
Cutting Forces ◽  
Chip Thickness ◽  
Dominant Frequency ◽  
Milling Process ◽  
Cutting Edge ◽  
Surface Generation ◽  
Uncut Chip Thickness ◽  
Improved Model

An improved model of the milling process is presented. The model proposes a method of determining cutting forces in five distinct regions where the cutting edge travels during dynamic milling. Trochoidal motion of the milling cutter is used in determining uncut chip thickness. The kinematics of the cutter and workpiece vibrations are modelled, which identifies the orientation and velocity direction of the cutting edge during dynamic cutting. The model allows the prediction of forces and surface finish under rigid or dynamic cutting conditions. The proposed mechanism of chip thickness, force and surface generation is proven with simulation and experimental results. It is found that when the tooth passing frequency is selected to be an integer ratio of a dominant frequency of tool-workpiece structure in milling imprint of vibrations on the surface finish is avoided.

A Micro Milling Model Considering Metal Phases and Minimum Chip Thickness

2008 ◽  
Vol 375-376 ◽  
pp. 505-509 ◽  
Author(s):  
Jin Sheng Wang ◽  
Jia Shun Shi ◽  
Ya Dong Gong ◽  
G. Abba ◽  
Guang Qi Cai
Keyword(s):  
Cutting Forces ◽  
Chip Thickness ◽  
Milling Process ◽  
Micro Milling ◽  
Surface Generation ◽  
Minimum Chip Thickness ◽  
Experiment Validation ◽  
Metal Phases

In this paper, a micro milling model is brought forward. The influences of different metal phases and the minimum chip thickness are considered in the model. The cutting forces and the surface generation in the micro milling process are predicted. Through the experiment validation, the results correlate to the model very well.

scholarly journals Temperature Distribution of Micro Milling Process due to Uncut Chip Thickness

2014 ◽  
Vol 939 ◽  
pp. 214-221 ◽  
Author(s):  
B.T.H.T. Baharudin ◽  
Kooi Pin Ng ◽  
S. Sulaiman ◽  
R. Samin ◽  
M.S Ismail
Keyword(s):  
Finite Element ◽  
Temperature Distribution ◽  
Model Validation ◽  
End Milling ◽  
Chip Thickness ◽  
Milling Process ◽  
Micro Milling ◽  
Work Piece ◽  
Workpiece Material ◽  
Undeformed Chip Thickness

A simplified model for micro milling process is presented, as well as results on temperature on tool and work piece. The purpose is to investigate on finite element modelling of two flute micro end milling process of titanium alloy, Ti6Al4V with prediction of temperature distribution. ABAQUS/Explicit has been chosen as solver for the analysis. A thermo-mechanical analysis was performed. First model was created by selecting medium carbon steel, AISI1045, as workpiece material for model validation purpose. Second model was created by modifying the workpiece material from AISI1045 to Ti6Al4V. The model consists of two parts which are tungsten carbide micro tool and workpiece. Johnson-Cook law model has been applied as material constitutive properties for both materials due to its severe plastic deformation occur during machining. Prediction on forces was obtained during the analysis. Model validation was done by comparing results published by Woon et al. in 2008. The results showed a good agreement in cutting force. Once this was proved, the same model was then modified to simulate finite element analysis in micro milling of Ti6Al4V. Prediction of temperature distribution of micro end mill of Ti6Al4V was done in relation of different undeformed chip thickness. The findings showed that temperature increases as undeformed chip thickness increases. Temperature distribution of Ti6Al4V and AISI1045 under same machining conditions was compared. Results showed that the highest temperature was concentrated at tool edge for Ti6Al4V.

scholarly journals Development and validation of a meshless 3D material point method for simulating the micro-milling process

2018 ◽  
Author(s):  
Sabine Leroch ◽  
Stefan J Eder ◽  
Georg Ganzenmüller ◽  
Jose Luis Sandoval Murillo ◽  
Manel Rodriguez Ripoll
Keyword(s):  
Finite Element ◽  
Cutting Forces ◽  
Chip Thickness ◽  
Material Point Method ◽  
Milling Process ◽  
Material Point ◽  
Finite Element Simulations ◽  
Point Method ◽  
Micro Milling ◽  
3D Simulations

A meshless Generalized Interpolation Material Point Method for simulating the micro-milling process was developed. This method has several advantages over well-established approaches (such as finite elements) when it comes to large plastic strains and deformations, since it inherently does not suffer from tensileinstability problems. The feasibility of the developed material point model for simulating micro-milling is verified against finite element simulations and experimental data. The model is able to successfully predict experimentally measured cutting forces and determine chip temperatures in agreement with conventional finite element simulations. After having verified the approach, the model was applied to perform extensive numerical 3D simulations of the micro-milling process. The goal is to evaluate the response of the micro-milling cutting forces as function of the hardening behavior of the micro-milled material. The meshless 3D simulations reveal a dependency of tool force slopes (with respect to the uncut chip thickness) on the hard-ening parameters. Based on these findings, a new approach is outlined to determine hardening parametersdirectly from two micro-milling experiments with distinct, sufficiently large uncut chip thicknesses.

CUTTING FORCES ANALYSIS IN WHIRLING PROCESS

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2786-2791 ◽  
Author(s):  
JAE HWAN SON ◽  
CHANG WOO HAN ◽  
SUN IL KIM ◽  
HEE CHUL JUNG ◽  
YOUNG MOON LEE
Keyword(s):  
Cutting Force ◽  
Chip Formation ◽  
Cutting Forces ◽  
Chip Thickness ◽  
Cutting Edge ◽  
Cutting Process ◽  
Undeformed Chip Thickness ◽  
Adams Software ◽  
Rotating Workpiece ◽  
Cutting Experiments

Whirling is a cutting process in which a series of cutting edges remove material by turning over the rotating workpiece. In this process, the whirling ring with a number of cutting teeth combined with the rotation and advancement of workpiece, produces pitches of worm. Mechanics of chip formation of the process, however, has not been fully estabilished. To estimate the cutting force during the process, the kinematics and the maximum undeformed chip thickness to be removed by each cutting edge should be thoroughly analyzed. In this study, using the recently developed model of undeformed chip thickness and the DEFORM software, cutting forces of the whirling process are estimated. The effects of cutting forces on tool are analyzed using the ADAMS software. The validity of the simulations has been verified with a series of cutting experiments.

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