scholarly journals Microstructure-Based 3D FE Modeling for Micro Cutting Ferritic-Pearlitic Carbon Steels

2014 ◽  
Author(s):  
M. Abouridouane ◽  
F. Klocke ◽  
D. Lung
Keyword(s):  
Size Effects ◽  
Chip Thickness ◽  
Rake Angle ◽  
Carbon Steels ◽  
Micro Milling ◽  
Fe Model ◽  
Two Phase ◽  
Workpiece Material ◽  
Micro Cutting ◽  
Feed Force

The mechanics of the cutting process on the microscopic level differ fundamentally from the conventional macro cutting. For example, the tool edge radius influences the cutting mechanism in micro machining significantly with regard to the effective rake angle, the minimum chip thickness, the dominance of ploughing, and the related elasto-plastic deformation of the workpiece material. These phenomena, known as size effects, have a profound impact on the cutting force, process stability, and resulting surface finish in micro cutting. Therefore, microstructural effects in microscale cutting require quite different assumptions to be made concerning underlying material behaviour during micro cutting and have led to the need for new modeling approaches to account for such effects. This paper presents a three-dimensional finite element approach to incorporate microstructure into micro cutting simulation based on the concept of a representative volume element (RVE) and constitutive material modeling as well as using the Lagrangian formulation proposed in the implicit FE code Deform 3D™. Micro drilling and micro milling tests using solid carbide tools with different diameters (d = 50 μm − 1 mm) were performed on ferrite-pearlite two-phase steel AISI 1045 for the verification of the developed 3D multiphase FE computation model regarding chip formation, feed force, and torque. The developed 3D multiphase FE model was successfully used to predict size effects in micro cutting.

Process-Independent Force Characterization for Metal-Cutting Simulation

1997 ◽  
Vol 119 (1) ◽  
pp. 86-94 ◽  
Author(s):  
D. A. Stephenson ◽  
P. Bandyopadhyay
Keyword(s):  
Metal Cutting ◽  
Cutting Speed ◽  
Chip Thickness ◽  
Rake Angle ◽  
Baseline Data ◽  
Empirical Equations ◽  
Machining Processes ◽  
Workpiece Material ◽  
Bar Turning ◽  
Force Data

Obtaining accurate baseline force data is often the critical step in applying machining simulation codes. The accuracy of the baseline cutting data determines the accuracy of simulated results. Moreover, the testing effort required to generate suitable data for new materials determines whether simulation provides a cost or time advantage over trial-and-error testing. The efficiency with which baseline data can be collected is limited by the fact that simulation programs do not use standard force or pressure equations, so that multiple sets of tests must be performed to simulate different machining processes for the same tool-workpiece material combination. Furthermore, many force and pressure equations do not include rake angle effects, so that separate tests are also required for different cutter geometries. This paper describes a unified method for simulating cutting forces in different machining processes from a common set of baseline data. In this method, empirical equations for cutting pressures or forces as a function of the cutting speed, uncut chip thickness, and tool normal rake angle are fit to baseline data from end turning, bar turning, or fly milling tests. Forces in specific processes are then calculated from the empirical equations using geometric transformations. This approach is shown to accurately predict forces in end turning, bar turning, or fly milling tests on five common tool-work material combinations. As an example application, bar turning force data is used to simulate the torque and thrust force in a combined drilling and reaming process. Extrapolation errors and corrections for workpiece hardness variations are also discussed.

scholarly journals Material microstructure effects in micro-endmilling of Cu99.9E

2016 ◽  
Vol 232 (7) ◽  
pp. 1143-1155 ◽  
Author(s):  
AM Elkaseer ◽  
SS Dimov ◽  
DT Pham ◽  
KP Popov ◽  
L Olejnik ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Grain Size ◽  
Chip Thickness ◽  
Micro Milling ◽  
Coarse Grained ◽  
Material Microstructure ◽  
Micro Cutting ◽  
Minimum Chip Thickness ◽  
Average Grain Size ◽  
Material Homogeneity

This article presents an investigation of the machining response of metallurgically and mechanically modified materials at the micro-scale. Tests were conducted that involved micro-milling slots in coarse-grained Cu99.9E with an average grain size of 30 µm and ultrafine-grained Cu99.9E with an average grain size of 200 nm, produced by equal channel angular pressing. A new method based on atomic force microscope measurements is proposed for assessing the effects of material homogeneity changes on the minimum chip thickness required for a robust micro-cutting process with a minimum surface roughness. The investigation has shown that by refining the material microstructure the minimum chip thickness can be reduced and a high surface finish can be obtained. Also, it was concluded that material homogeneity improvements lead to a reduction in surface roughness and surface defects in micro-cutting.

Finite Element Modelling and Analysis of Cutting-Direction Burr Formation

2008 ◽  
Vol 392-394 ◽  
pp. 88-92
Author(s):  
Xiao Wang ◽  
H. Yan ◽  
C. Liang ◽  
B. Wu ◽  
Hui Xia Liu ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Metal Cutting ◽  
Chip Thickness ◽  
Element Model ◽  
Rake Angle ◽  
Burr Formation ◽  
Workpiece Material ◽  
Orthogonal Machining ◽  
Cutting Direction

To prevent or reduce the formation of burr efficiently in metal cutting, it is necessary to reveal the burr formation mechanism. A finite element model of cutting-direction burr formation in orthogonal machining was presented in this paper. The simulation of the burr formation process was conducted. Undeformed chip thickness, rake angle, rounded cutting edge radius and workpiece material were included in cutting conditions, whose influences on burr formation were investigated, according to the simulation results. By comparing the results of the simulation and the experiment, good consistency is achieved which proves that the finite element model of burr formation in this paper is significant and effective to predict burr formation.

Impact of Spindle Speed on Micro-Milling Stability

2012 ◽  
Author(s):  
Eric B. Halfmann ◽  
C. Steve Suh
Keyword(s):  
Slip Line ◽  
Chip Thickness ◽  
Rake Angle ◽  
Micro Milling ◽  
Work Piece ◽  
Formation Mechanisms ◽  
Lumped Mass ◽  
Effective Rake Angle ◽  
Helical Angle ◽  
Force Mechanism

Milling efficiency is hampered by excessive tool vibrations that negatively impact the work-piece quality. This is more of a concern in micro-milling where sudden tool breakage occurs before the operator can adjust cutting parameters. Due to different chip formation mechanisms in micro-milling, an increased tool-radius to feed-rate ratio, and higher spindle speeds, micro-milling is a highly non-linear process which can produce multiple and broadband frequencies which increase the probability of tool failure. Micro-milling is studied through the development and analysis of a 3-D nonlinear micro-milling dynamic model. A lumped mass, spring, damper system is assumed for modeling the dynamic properties of the tool. The force mechanism utilized is a slip-line field model that provides the advantages of being highly dynamic by accounting for the constantly changing effective rake angle and slip-line variables. Accurate prediction of the chip thickness is important in correctly predicting the dynamics of the system since the force mechanism and its variables are a function of the chip thickness. A novel approach for calculating the instantaneous chip thickness which accounts for the tool jumping out of the cut and elastic recovery of the work-piece is presented. The effective rake angle and helical angle is accounted for resulting in a 3-D micro-milling model. The model is shown to resolve the high frequency force components that are seen in experimental data available in literature. Also, exciting the system at various spindle speeds results in dynamic states of motion that negatively impact the process through increased vibration amplitude and a broad frequency bandwidth.

Determination of Cutting Forces for Micro Milling

2008 ◽  
Author(s):  
Shih-Ming Wang ◽  
Zou-Sung Chiang ◽  
Da-Fun Chen
Keyword(s):  
Cutting Force ◽  
Chip Thickness ◽  
Cutting Parameters ◽  
Rake Angle ◽  
Micro Milling ◽  
Force Model ◽  
Machining Parameters ◽  
Cutting Force Model ◽  
Optimal Cutting Parameters

To enhance the implementation of micro milling, it is necessary to clearly understand the dynamic characteristics of micro milling so that proper machining parameters can be used to meet the requirements of application. By taking the effect of minimum chip thickness and rake angle into account, a new cutting force model of micro-milling which is function the instantaneous cutting area and machining coefficients was developed. According to the instantaneous rotation trajectory of cutting edge, the cutting area projected to xy-plane was determined by rectangular integral method, and used to solve the instantaneous cutting area. After the machining coefficients were solved, the cutting force of micro-milling for different radial depths of cut and different axial depths of cut can be predicted. The results of micro-milling experimental have shown that the force model can predict the cutting force accurately by which the optimal cutting parameters can be selected for micro-milling application.

scholarly journals Experimental Study on the Minimum Undeformed Chip Thickness Based on Effective Rake Angle in Micro Milling

Micromachines ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 924
Author(s):  
Xian Wu ◽  
Li Liu ◽  
Mingyang Du ◽  
Jianyun Shen ◽  
Feng Jiang ◽  
...  
Keyword(s):  
Averaging Method ◽  
Chip Thickness ◽  
Rake Angle ◽  
Cutting Process ◽  
Micro Milling ◽  
Undeformed Chip Thickness ◽  
Effective Rake Angle ◽  
Force Signal ◽  
Micro Parts ◽  
Tool Cutting

Micro milling is widely used to manufacture micro parts due to its obvious advantages. The minimum undeformed chip thickness, the effective rake angle, and size effect are the typical characteristics and closely related to each other in micro milling. In this paper, the averaging method is proposed to quantitatively estimate the effective rake angle in the cutting process. The minimum undeformed chip thickness is explained based on the effective rake angle and determined to be 0.17 rn (tool cutting edge radius). Then, micro milling experiment was conducted to study the effect of the minimum undeformed chip thickness. It is found that the minimum undeformed chip thickness results in the unstable cutting process, the uneven peaks on cutting force signal, and the dense characteristic frequency distribution on frequency domain signal. The dominant ploughing effect induces the great specific cutting energy and the deteriorated surface roughness due to the minimum undeformed chip thickness.

High Speed Non-Linear Micro-Milling Dynamics

2012 ◽  
Author(s):  
Eric B. Halfmann ◽  
C. Steve Suh
Keyword(s):  
Slip Line ◽  
Chip Thickness ◽  
Rake Angle ◽  
Micro Milling ◽  
Work Piece ◽  
Formation Mechanisms ◽  
Effective Rake Angle ◽  
Non Linear ◽  
Force Mechanism ◽  
Milling Dynamics

The efficiency of the milling process is limited due to excessive vibrations that negatively impact the tool and work-piece quality. This becomes even more of a concern in micro-milling where sudden tool breakage occurs before the operator can adjust cutting parameters. Due to different chip formation mechanisms in micro-milling, an increased tool-radius to feed-rate ratio, and higher spindle speeds, micro-milling is a highly non-linear process which can produce multiple and broadband frequencies which increase the probability of tool failure. This paper investigates micro-milling through the development and analysis of a 3-D nonlinear micro-milling dynamic model. A lumped mass, spring, damper system is assumed for modeling the dynamic properties of the tool. The force mechanism utilized is a slip-line field model that provides the advantages of being highly dynamic by accounting for the constantly changing effective rake angle and slip-line variables. Accurate prediction of the chip thickness is important in correctly predicting the dynamics of the system since the force mechanism and its variables are a function of the chip thickness. A novel approach for calculating the instantaneous chip thickness which accounts for the tool jumping out of the cut and elastic recovery of the work-piece is presented. The derivation for the effective rake angle is given and the helical angle is accounted for resulting in a 3-D micro-milling model. The results of simulating the model demonstrate its capability of producing the high frequency force components that are seen in experimental data available in literature. The advantages of using this approach over the constant empirical force coefficient approach when studying micro-milling dynamics is discussed and the instability of the system is investigated utilizing instantaneous frequency.

A Lagrangian FEM Model to Produce Saw-Toothed Macro-Chip and to Study the Depth of Cut Influence on its Formation in Orthogonal Cutting of Ti6Al4V

2011 ◽  
Vol 223 ◽  
pp. 3-11 ◽  
Author(s):  
François Ducobu ◽  
Edouard Rivière-Lorphèvre ◽  
Enrico Filippi
Keyword(s):  
Orthogonal Cutting ◽  
Chip Thickness ◽  
Chip Morphology ◽  
Rake Angle ◽  
Micro Milling ◽  
Depth Of Cut ◽  
Fem Model ◽  
Minimum Chip Thickness ◽  
Thickness Prediction ◽  
On Chip

The foundations of micro-milling are similar to macro-milling but the phenomena it involves are not a simple scaling-down of macro-cutting. The importance of the minimum chip thickness is one of the significant differences between the two processes. The lagrangian FEM model presented in this paper aims to study the depth of cut influence on chip formation of Ti6Al4V in orthogonal cutting. It is firstly used to compare the modelled saw-toothed macro-chip morphology and cutting forces to experimental cutting results from literature. Then a minimum chip thickness prediction is performed by decreasing the depth of cut. Finally this study is the opportunity to highlight the specific features of micro-cutting reported in literature, such as the effective negative rake angle of the tool or the size effect. The model presented brings therefore a numerical contribution to the comprehension of these phenomena.

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.

Finite Element Model and Analysis for Micro-Cutting of Aluminum Alloy 7050-T7451

2012 ◽  
Vol 566 ◽  
pp. 650-653 ◽  
Author(s):  
Fu Zeng Wang ◽  
Jie Sun ◽  
Pei Qin Sun ◽  
Jun Zhou
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Cutting Force ◽  
Chip Thickness ◽  
Element Model ◽  
Actual State ◽  
Depth Of Cut ◽  
Fe Model ◽  
Uncut Chip Thickness ◽  
Micro Cutting

In this paper, a finite element model with respect to actual state of micro-cutting is established by adopting software of ABAQUS/Explicit. Based on the FE model, the cutting force and specific cutting force with various uncut depth of cut with different cutting edge radius are compared and then analyzed with regard to this simulation. In micro-cutting, the nonlinear scaling phenomenon is more evident with the decreasing of uncut chip thickness. The likely explanations for the size effect in small uncut chip thickness are discussed in this paper.

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