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.

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.

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.

scholarly journals Chatter Behavior in the Milling Process of Inconel 718: Effects of Tool Edge Radius

2018 ◽  
Vol 202 ◽  
pp. 02006
Author(s):  
C H Hoe ◽  
M M Reddy ◽  
V C C Lee ◽  
S Debnath
Keyword(s):  
Inconel 718 ◽  
Elevated Temperatures ◽  
Milling Process ◽  
Machining Process ◽  
Chatter Vibration ◽  
End Mill ◽  
Tool Edge Radius ◽  
Edge Radius ◽  
Tool Edge ◽  
Variable Helix

Inconel 718 is widely used in various high end industries such as aerospace, nuclear plant, petrochemical plants etc. Inconel 718 is used for these applications due to unique mechanical properties such as high mechanical strength at elevated temperatures, high resistance to corrosion, and high strength to weight ratio. The unique properties of Inconel 718 made it difficult to be machined due to rapid work hardening and high cutting temperature. In addition, chatter vibration further increases the difficulty in machining of Inconel 718. In this paper, an experimental study on the effects of tool edge radius to the chatter behaviour was investigated. The dynamic responses of the milling process were recorded and analysed in both time domain and frequency domain. The results showed the variable helix and pitch end mill tool with larger tool edge radius able to mitigate chatter vibration at lower cutting speeds. Variable helix and pitch end mill with specific tool edge radius able to mitigate chatter vibration under the same cutting parameters. Experiments shows proper selection of tool edge radius improves the stability of end milling machining process.

Finite Element Modeling for High Speed Machining of Ti-6Al-4V Using ALE Boundary Technology

2011 ◽  
Vol 66-68 ◽  
pp. 1509-1514
Author(s):  
Dong Lu ◽  
Ming Ming Yang ◽  
Hong Fu Huang ◽  
Xiao Hong Zhong
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
High Speed ◽  
Element Model ◽  
Machining Process ◽  
Computational Time ◽  
High Speed Machining ◽  
Tool Edge Radius ◽  
Edge Radius ◽  
Tool Edge

A finite element model of HSM (High Speed Machining) process of Ti6Al4V was developed with Abaqus 6.10. The flow stress of Ti6Al4V is taken as a function of strain, strain rate and temperature. Considering the fact that the tool edge radius is relatively large in HSM of Ti6Al4V and significantly influences the mechanical behaviour, thus a new Arbitrary Lagrangian-Eulerian (ALE) boundary technology was incorporated into the finite element model to simulate the flowing material around the tool edge.The adoption of ALE boundary technology could avoid using the traditional chip separation criterias and element deletion method in the model, which at the same time results in the less excessive element distortion and computational time in comparison with traditional finite element models of cutting process. The simulation results of Cutting force and temperature close to the experimental values in an acceptable range could be obtained and a stagnant zone in front of the tool edge was successfully observed in this new developed model with large tool edge radius.

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.

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