Study on Unique Cutting Phenomena in Micro Endmilling - Mechanism and Possibility to Occur-

2009 ◽  
Vol 76-78 ◽  
pp. 508-513 ◽  
Author(s):  
Mitsuyoshi Nomura ◽  
Takahiro Kawashima ◽  
Takayuki Shibata ◽  
Yoshihiko Murakami ◽  
Masami Masuda ◽  
...  
Keyword(s):  
Tool Wear ◽  
Computer Simulations ◽  
Surface Finish ◽  
Chip Thickness ◽  
Cutting Process ◽  
Uncut Chip Thickness ◽  
Tool Edge Radius ◽  
Edge Radius ◽  
Tool Edge

In micro endmilling, because of small uncut chip thickness comparable to the tool edge radius and low rigidity of tool, the cutting process must frequently transit between rubbing/ploughing and cutting, and it may deteriorate the machining stability, surface finish and tool wear. In this report, such unique cutting phenomena are investigated by modeling a mechanism, computer simulations and experiments. As a result, a possibility of the unique cutting phenomena proposed has been certified.

An Analytical Model for the Prediction of Minimum Chip Thickness in Micromachining

2005 ◽  
Vol 128 (2) ◽  
pp. 474-481 ◽  
Author(s):  
X. Liu ◽  
R. E. DeVor ◽  
S. G. Kapoor
Keyword(s):  
Analytical Model ◽  
Chip Thickness ◽  
Machining Process ◽  
Thickness Effect ◽  
Uncut Chip Thickness ◽  
Minimum Chip Thickness ◽  
Tool Edge Radius ◽  
Edge Radius ◽  
Tool Edge ◽  
Cutting Velocity

In micromachining, the uncut chip thickness is comparable or even less than the tool edge radius and as a result a chip will not be generated if the uncut chip thickness is less than a critical value, viz., the minimum chip thickness. The minimum chip thickness effect significantly affects machining process performance in terms of cutting forces, tool wear, surface integrity, process stability, etc. In this paper, an analytical model has been developed to predict the minimum chip thickness values, which are critical for the process model development and process planning and optimization. The model accounts for the effects of thermal softening and strain hardening on the minimum chip thickness. The influence of cutting velocity and tool edge radius on the minimum chip thickness has been taken into account. The model has been experimentally validated with 1040 steel and Al6082-T6 over a range of cutting velocities and tool edge radii. The developed model has then been applied to investigate the effects of cutting velocity and edge radius on the normalized minimum chip thickness for various carbon steels with different carbon contents and Al6082-T6.

Determination of Minimum Uncut Chip Thickness in Micromachining

2009 ◽  
Vol 69-70 ◽  
pp. 408-412 ◽  
Author(s):  
Zhen Yu Shi ◽  
Zhan Qiang Liu
Keyword(s):  
Surface Deformation ◽  
Geometric Model ◽  
Chip Thickness ◽  
Uncut Chip Thickness ◽  
Tool Edge Radius ◽  
Minimum Value ◽  
Edge Radius ◽  
Cutting Surface ◽  
Minimum Uncut Chip Thickness ◽  
Tool Edge

In micromachining, the uncut chip thickness is comparable to the tool edge radius, and chip won’t be generated if the uncut chip thickness is less than a critical value, besides that, the minimum uncut chip thickness affect many factors such as the cutting force, the chip’s modality, the cutting surface quality, etc. In this paper, a geometric model is developed to predict the minimum uncut chip thickness values. The model accounts for the theory that the critical condition of producing chip is when the friction of the surface deformation asperities is zero. Two situations when the minimum value is larger or smaller than the tool edge radius respectively to predict the minimum value are discussed. The influences of tool edge radius and material’s property on the minimum uncut chip thickness are taken into account.

A Study of Exit-Burr Formation Mechanism Using the Finite Element Method in Micro-Cutting of Aluminum Alloy

2008 ◽  
Vol 375-376 ◽  
pp. 470-473 ◽  
Author(s):  
Dong Lu ◽  
Jian Feng Li ◽  
Yi Ming Rong ◽  
Jie Sun ◽  
Jun Zhou ◽  
...  
Keyword(s):  
Cutting Speed ◽  
Chip Thickness ◽  
Burr Formation ◽  
Uncut Chip Thickness ◽  
Micro Cutting ◽  
Tool Edge Radius ◽  
Edge Radius ◽  
Tool Edge ◽  
Speed Effect ◽  
Exit Burr

A burr formation process in micro-cutting of Al7075-T7451 was analyzed. Three stages of burr formation including steady-state cutting stage, pivoting stage, and burr formation stage are investigated. And the effects of uncut chip thickness, cutting speed and tool edge radius on the burr formation are studied. The simulation results show that the generation of negative shear zone is one of the prime reasons for burr formation. Uncut chip thickness has a significant effect on burr height; however, the cutting speed effect is minor. Unlike in conventional cutting, in micro-cutting the effect of tool edge radius on the burr geometry can no longer be neglected.

Simulation of Meso-Scale Machining of AISI1045 Based on Multiphase Model

2016 ◽  
Vol 836-837 ◽  
pp. 374-380
Author(s):  
Teng Yi Shang ◽  
Li Jing Xie ◽  
Xiao Lei Chen ◽  
Yu Qin ◽  
Tie Fu
Keyword(s):  
Cutting Force ◽  
Cutting Process ◽  
Multiphase Model ◽  
Tool Edge Radius ◽  
Edge Radius ◽  
Tool Edge ◽  
Cutting Insert ◽  
Multiphase Models ◽  
Hot Rolled ◽  
Meso Scale

In the meso-scale machining, feed rate, grain size and tool edge radius are in the same order of magnitude, and cutting process is often carried out in the grain interior and grain boundary. In this paper the meso-cutting process of hot-rolled AISI1045 steel is studied and its metallographic microstructure is analyzed for the establishment of multiphase models which incorporate the effect of ferrite and pearlite grains. In order to discover the applicability of multiphase models to the simulation of meso-cutting, three contrast simulation models including multiphase model with rounded-edge cutting insert (model I), multiphase model with sharp edge cutting insert (model II) and equivalent homogeneous material model with rounded-edge cutting insert (model III) are built up for the meso-orthogonal cutting processes of hot-rolled AISI1045. By comparison with the experiments in terms of chip morphology, cutting force and specific cutting force, the most suitable model is identified. Then the stress distiribution is analyzed. And it is found that multiphase model with tool edge radius can give a more accurate prediction of the global variables and reveal more about these important local variables distribution.

Investigation of effect of uncut chip thickness to edge radius ratio on nanoscale cutting behavior of single crystal copper: MD simulation approach

2020 ◽  
pp. 251659842093763
Author(s):  
A. Sharma ◽  
P. Ranjan ◽  
R. Balasubramaniam
Keyword(s):  
Molecular Dynamics ◽  
Single Crystal ◽  
Material Removal ◽  
Chip Thickness ◽  
Cutting Process ◽  
Uncut Chip Thickness ◽  
Edge Radius ◽  
Nanoscale Cutting ◽  
Cutting Behavior ◽  
Subsurface Defects

Extremely small cutting depths in nanoscale cutting makes it very difficult to measure the thermodynamic properties and understand the underlying mechanism and behavior of workpiece material. Highly precise single-crystal Cu is popularly employed in optical and electronics industries. This study, therefore, implements the molecular dynamics technique to analyze the cutting behavior and surface and subsurface phenomenon in the nanoscale cutting of copper workpieces with a diamond tool. Molecular dynamics simulation is carried out for different ratios of uncut chip thickness ( a) to cutting edge radius ( r) to investigate material removal mechanism, cutting forces, surface and subsurface defects, material removal rate (MRR), and stresses involved during the nanoscale cutting process. Calculation of forces and amount of plowing indicate that a/ r = 0.5 is the critical ratio for which the average values of both increase to maximum. Material deformation mechanism changes from shear slip to shear zone deformation and then to plowing and elastic rubbing as the cutting depth/uncut chip thickness is reduced. The deformation during nano-cutting in terms of dislocation density changes with respect to cutting time. During the cutting process, it is observed that various subsurface defects like point defects, dislocations and dislocation loops, stacking faults, and stair-rod dislocation take place.

The Influence of Tool Edge Radius on Size Effect in Orthogonal Micro-Cutting Process of 7050-T7451 Aluminum Alloy

2008 ◽  
Vol 375-376 ◽  
pp. 31-35
Author(s):  
Jun Zhou ◽  
Jian Feng Li ◽  
Jie Sun ◽  
Zhi Ping Xu
Keyword(s):  
Aluminum Alloy ◽  
Size Effect ◽  
Cutting Force ◽  
Chip Thickness ◽  
Specific Cutting Energy ◽  
Uncut Chip Thickness ◽  
Tool Edge Radius ◽  
Specific Cutting Force ◽  
Cutting Energy ◽  
Tool Edge

In machining, the size effect is typically characterized by a non-linear increase in the specific cutting energy (or specific cutting force) as the uncut chip thickness is decreased. A finite element model of orthogonal micro-cutting was established to study the influence of tool edge radius on size effect when cutting 7050-T7451 aluminum alloy. Diamond cutting tool was used in the simulation. Specific cutting force and specific cutting energy are obtained through the simulation. The nonlinear scaling phenomenon is evident. The likely explanations for the size effect in small uncut chip thickness were discussed in this paper.

Tool Edge Roundness and Stable Build-Up Formation in Finish Machining

1974 ◽  
Vol 96 (4) ◽  
pp. 1258-1267 ◽  
Author(s):  
M. Es. Abdelmoneim ◽  
R. F. Scrutton
Keyword(s):  
Theoretical Analysis ◽  
Cutting Force ◽  
Specific Energy ◽  
Chip Thickness ◽  
Force Measurements ◽  
Undeformed Chip Thickness ◽  
Velocity Discontinuity ◽  
Tool Edge Radius ◽  
Edge Radius ◽  
Tool Edge

The results of cutting force measurements when machining materials which do not form a sizable unstable built-up-edge are compared with the results of a theoretical analysis. This analysis, based partly on the use of circular cylindrical surfaces of velocity discontinuity around the base of the tool, yields specific energy values which are uniquely determined by the value of the undeformed chip thickness in relation to the tool edge radius.

Extracting Specific Cutting Force Coefficients in Micro Drilling with Tool Edge Radius Effects

2015 ◽  
Vol 799-800 ◽  
pp. 256-260 ◽  
Author(s):  
Ravi Shankar Anand ◽  
Karali Patra
Keyword(s):  
Cutting Force ◽  
Thrust Force ◽  
Chip Thickness ◽  
Cutting Force Coefficients ◽  
Undeformed Chip Thickness ◽  
Tool Edge Radius ◽  
Cutting Coefficients ◽  
Edge Radius ◽  
Tool Edge ◽  
Micro Drilling

This article introduces a methodology for extracting specific cutting force coefficients by performing micro drilling experiments with tool edge radius effect.Tool edge radius mainly affects the effective rake angle that varies according to undeformed chip thickness. Ploughing effect is also considered for undeformed chip thickness lower than the minimum chip thickness. In this work specific normal and frictional cutting coefficients for both ploughing and shearing are determined from mechanistic approach of fitting experimental specific thrust forces of the micro drilling process. The variations of these cutting coefficients with respect to cutting speedand feed are presented. Finally these coefficients have been applied to the mechanistic model to predict thrust force in micro drilling. The predicted thrust force values at different feed show good agreement with the experimental results.

A Non-Dimensional Analysis of Tool Edge Radius Effect on the Mechanics of Micromachining

2012 ◽  
Vol 565 ◽  
pp. 576-581
Author(s):  
Keng Soon Woon ◽  
Mustafizur Rahman ◽  
Kui Liu
Keyword(s):  
Dimensional Analysis ◽  
Chip Thickness ◽  
Contact Length ◽  
Extreme Condition ◽  
Process Variables ◽  
Tool Edge Radius ◽  
Edge Radius ◽  
Machining Force ◽  
Tool Edge ◽  
Chip Formation Mechanism

The effect of tool edge radius on the mechanics of micromachining, both in terms of plasticity and tribology is significant. Through an experimental study, the responses of normalized process variables namely tool-chip contact length, deformed chip thickness and machining force were evaluated for varying relative tool sharpness. A non-dimensional analysis of the interrelationship among the process variables indicate a transformation in chip formation mechanism under an extreme condition is reported.

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