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.

The Constant Force Component due to Material Separation and Its Contribution to the Size Effect in Specific Cutting Energy

2005 ◽  
Vol 128 (3) ◽  
pp. 811-815 ◽  
Author(s):  
Sathyan Subbiah ◽  
Shreyes N. Melkote
Keyword(s):  
Size Effect ◽  
Cutting Force ◽  
Orthogonal Cutting ◽  
Chip Thickness ◽  
Constant Force ◽  
Specific Cutting Energy ◽  
Force Component ◽  
Uncut Chip Thickness ◽  
Cutting Energy ◽  
Material Separation

The contribution of material separation in cutting ductile metals to the constant force component, and, hence, to the size effect in specific cutting energy is explored in this paper. A force-decomposition-based framework is proposed to reconcile the varied reasons given in literature for the size effect. In this framework, the cutting force is broken down into three components: one that is decreasing, another that is increasing, and the third that remains constant, with decreasing uncut chip thickness. The last component is investigated by performing orthogonal cutting experiments on OFHC copper at high rake angles of up to 70deg in an attempt to isolate it. As the rake angle is increased, the resulting experimental data show a trend toward a constant cutting-force component independent of the uncut chip thickness. Visual evidence of ductile tearing ahead of the tool associated with material separation leading to chip formation is shown. The measured constant force and the force needed for ductile crack extension are then compared.

On the Size-Effect in Micro-Cutting at Low and High Rake Angles

2004 ◽  
Author(s):  
Sathyan Subbiah ◽  
Shreyes N. Melkote
Keyword(s):  
Size Effect ◽  
Cutting Force ◽  
Constant Width ◽  
Orthogonal Cutting ◽  
Chip Thickness ◽  
Cutting Condition ◽  
Specific Cutting Energy ◽  
Uncut Chip Thickness ◽  
Micro Cutting ◽  
Cutting Energy

A partial explanation of the size-effect in the specific cutting energy in micro-cutting is provided in this paper. For a simple orthogonal cutting condition, with constant width of cut, the specific cutting energy is viewed as a ratio of the cutting force and the uncut chip thickness. Size-effect, i.e., an unbounded increase in the specific cutting energy with decrease in uncut chip thickness, will occur under two conditions: one, if a component of the cutting force remains constant with uncut chip thickness and two, if some component of the cutting force increases with the uncut chip thickness. Experiments have been performed at high rake angles in an attempt to isolate and detect the presence of the constant component of the cutting force. The trend confirming the presence of this component is reported and explained.

Material Strengthening Mechanisms and Their Contribution to Size Effect in Micro-Cutting

2005 ◽  
Author(s):  
Kai Liu ◽  
Sathyan Subbiah ◽  
Shreyes N. Melkote
Keyword(s):  
Size Effect ◽  
Strain Rate ◽  
Strain Gradient ◽  
Orthogonal Cutting ◽  
Chip Thickness ◽  
Material Strength ◽  
Specific Cutting Energy ◽  
Uncut Chip Thickness ◽  
Cutting Energy ◽  
Secondary Deformation

The specific cutting energy in machining is known to increase nonlinearly with decrease in uncut chip thickness. It has been reported in the literature that this phenomenon is dependent on several factors such as material strengthening, ploughing due to finite edge radius, and material separation effects. This paper examines the material strengthening effect where the material strength increases as the uncut chip thickness decreases down to a few microns. This increase in strength has been attributed to various factors such as strain-rate, strain gradient and temperature effects. Given that the increase in material strength in the primary and secondary deformation zones can occur due to many factors, it is important to understand the contributions of each factor to the increase in specific cutting energy and the conditions under which they are dominant. This paper analyzes two material strengthening factors: (i) the contribution of the decrease in the secondary deformation zone cutting temperature, and (ii) strain gradient strengthening, and their relative contributions to the increase in specific cutting energy as the uncut chip thickness is reduced. Finite Element (FE) based orthogonal cutting simulations are performed using aluminum 5083-H116, a work material with a small strain-rate hardening exponent, thus minimizing strain-rate effect. Suitable cutting conditions are identified under which the temperature and strain gradient effects are dominant. Orthogonal cutting experiments are used to validate the model in terms of the cutting forces. The simulation results are then analyzed to identify the contributions of the material strengthening factors to the size effect in specific cutting energy.

Material Strengthening Mechanisms and Their Contribution to Size Effect in Micro-Cutting

2005 ◽  
Vol 128 (3) ◽  
pp. 730-738 ◽  
Author(s):  
Kai Liu ◽  
Shreyes N. Melkote
Keyword(s):  
Size Effect ◽  
Strain Rate ◽  
Strain Gradient ◽  
Orthogonal Cutting ◽  
Chip Thickness ◽  
Material Strength ◽  
Strengthening Effect ◽  
Specific Cutting Energy ◽  
Uncut Chip Thickness ◽  
Cutting Energy

The specific cutting energy in machining is known to increase nonlinearly with decrease in uncut chip thickness. It has been reported in the literature that this phenomenon is dependent on several factors such as material strengthening, ploughing due to finite edge radius, and material separation effects. This paper examines the material strengthening effect where the material strength increases nonlinearly as the uncut chip thickness is reduced to a few microns. This increase in strength has been attributed in the past to various factors such as strain rate, strain gradient, and temperature effects. Given that the increase in material strength can occur due to many factors, it is important to understand the contributions of each factor to the increase in specific cutting energy and the conditions under which they are dominant. This paper analyzes two material strengthening factors, (i) the contribution of the decrease in the secondary deformation zone cutting temperature and (ii) strain gradient strengthening, and their relative contributions to the increase in specific cutting energy as the uncut chip thickness is reduced. Finite element (FE)-based orthogonal cutting simulations are performed with Aluminum 5083-H116, a work material with a small strain rate hardening exponent, thus minimizing strain rate effects. Suitable cutting conditions are identified under which the temperature and strain gradient effects are dominant. Orthogonal cutting experiments are used to validate the model in terms of cutting forces. The simulation results are then analyzed to identify the contributions of the material strengthening factors to the size effect in specific cutting energy.

Experimental Investigations of Size Effect on Cutting Force, Specific Cutting Energy, and Surface Integrity during Micro Cutting

2012 ◽  
Vol 723 ◽  
pp. 371-376
Author(s):  
Tao Zhang ◽  
Zhan Qiang Liu ◽  
Chong Hai Xu ◽  
Ning He ◽  
Liang Li
Keyword(s):  
Size Effect ◽  
Surface Integrity ◽  
Chip Thickness ◽  
Cutting Edge ◽  
Specific Cutting Energy ◽  
Uncut Chip Thickness ◽  
Micro Cutting ◽  
Burr Height ◽  
Cutting Energy ◽  
Exit Burr

Micro cutting is a promising technology to manufacture the micro parts. The shear mechanism of micro cutting is different from the conventional cutting due to the round cutting edge. The ratio of uncut chip thickness to cutting edge radius plays an important role on the micro cutting process. This paper investigates the size effect phenomena of micro cutting. Firstly, the cutting force and size effect of specific cutting energy depending on the ratio of uncut chip thickness to cutting edge radius are analyzed according to the experimental results. Then, the size effect of surface roughness due to the size effect of specific cutting energy is explored. Lastly, the size effect of the exit burr height is depicted and the potential reason is analyzed. The paper supplies a good understanding of how to get the best surface integrity and minimize the exit burr height for micro cutting.

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.

Finite Element Analysis of Cutting Force and Burr Formation in Micro-Cutting of Titanium Alloy Considering Tool Edge Radius

2012 ◽  
Vol 426 ◽  
pp. 235-238 ◽  
Author(s):  
Da Peng Dong ◽  
Xiao Hu Zheng ◽  
Ming Chen ◽  
Qing Long An
Keyword(s):  
Cutting Force ◽  
Simulation Modeling ◽  
Burr Formation ◽  
Element Analysis ◽  
Micro Cutting ◽  
Tool Edge Radius ◽  
Cutting Energy ◽  
Burr Size ◽  
Edge Radius ◽  
Tool Edge

In recent years, with the development of machinery industry, micro-cutting technologies have been gradually moving into engineering realization. The paper carries out a series of works on simulation modeling of micro-cutting of Ti-5Al-5V-5Mo-3Cr considering tool edge radius. Unlike conventional cutting, in micro-cutting the effect of tool edge radius which has a marked impact on cutting force, specific cutting energy, burr formation and burr size can no longer be neglected.

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.

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.

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