scholarly journals Influence of the Rake Angle on Nanocutting of Fe Single Crystals: A Molecular-Dynamics Study

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 516 ◽  
Author(s):  
Iyad Alabd Alhafez ◽  
Herbert M. Urbassek
Keyword(s):  
Molecular Dynamics ◽  
Chip Thickness ◽  
Mass Conservation ◽  
Friction Angle ◽  
Rake Angle ◽  
Shear Angle ◽  
Dynamics Simulation ◽  
Burgers Vector ◽  
Edge Dislocations ◽  
Cutting Direction

Using molecular dynamics simulation, we study the cutting of an Fe single crystal using tools with various rake angles α . We focus on the (110)[001] cut system, since here, the crystal plasticity is governed by a simple mechanism for not too strongly negative rake angles. In this case, the evolution of the chip is driven by the generation of edge dislocations with the Burgers vector b = 1 2 [ 111 ] , such that a fixed shear angle of ϕ = 54.7 ∘ is established. It is independent of the rake angle of the tool. The chip form is rectangular, and the chip thickness agrees with the theoretical result calculated for this shear angle from the law of mass conservation. We find that the force angle χ between the direction of the force and the cutting direction is independent of the rake angle; however, it does not obey the predictions of macroscopic cutting theories, nor the correlations observed in experiments of (polycrystalline) cutting of mild steel. Only for (strongly) negative rake angles, the mechanism of plasticity changes, leading to a complex chip shape or even suppressing the formation of a chip. In these cases, the force angle strongly increases while the friction angle tends to zero.

A New Model and Analysis of Orthogonal Machining With an Edge-Radiused Tool

1999 ◽  
Vol 122 (3) ◽  
pp. 384-390 ◽  
Author(s):  
Jairam Manjunathaiah ◽  
William J. Endres
Keyword(s):  
Shear Stress ◽  
Deformation Zone ◽  
Lower Boundary ◽  
Chip Thickness ◽  
Rake Angle ◽  
Shear Angle ◽  
Force Model ◽  
Uncut Chip Thickness ◽  
Edge Radius ◽  
Machining Force

A new machining process model that explicitly includes the effects of the edge hone is presented. A force balance is conducted on the lower boundary of the deformation zone leading to a machining force model. The machining force components are an explicit function of the edge radius and shear angle. An increase in edge radius leads to not only increased ploughing forces but also an increase in the chip formation forces due to an average rake angle effect. Previous attempts at assessing the ploughing components as the force intercept at zero uncut chip thickness, which attribute to the ploughing mechanism all the changes in forces that occur with changes in edge radius, are seen to be erroneous in view of this model. Calculation of shear stress on the lower boundary of the deformation zone using the new machining force model indicates that the apparent size effect when cutting with edge radiused tools is due to deformation below the tool (ploughing) and a larger chip formation component due to a lower shear angle. Increases in specific energy and shear stress are also due to shear strain and strain rate increases. A consistent material behavior model that does not vary with process input conditions like uncut chip thickness, rake angle and edge radius can be developed based on the new model. [S1087-1357(00)01302-2]

Experimental Study on the Chip Geometry and Shear Angle in Micro-Cutting Aluminum 7050-T7451

2010 ◽  
Vol 443 ◽  
pp. 657-662
Author(s):  
Jun Zhou ◽  
Jian Feng Li ◽  
Jie Sun
Keyword(s):  
Cutting Speed ◽  
Chip Thickness ◽  
Rake Angle ◽  
Shear Angle ◽  
Micro Scale ◽  
Effective Rake Angle ◽  
Al 7075 ◽  
Chip Geometry ◽  
Cutting Experiments ◽  
Machining Characteristics

In this paper, the micro-scale machining characteristics of a non-ferrous structural alloy, aluminum 7050-T7451 is investigated through a series of cutting experiments. The effects of cutting speed and undeformed chip thickness on the chip geometry, cutting ratio, effective rake angle and shear angle in orthogonal micro-scale cutting of Al 7075-T7451 are presented. Explanations for the observed trends are also given.

scholarly journals Glide Mobility of a-Type Edge Dislocations in Aluminum Nitride by Molecular Dynamics Simulation

ACS Omega ◽  
2021 ◽  
Author(s):  
Yinting Zhao ◽  
Danyang Fu ◽  
Qikun Wang ◽  
Jiali Huang ◽  
Dan Lei ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Aluminum Nitride ◽  
Dynamics Simulation ◽  
Edge Dislocations

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.

Al-Film/Si-Substrate System Nanoscratching Response Based upon Molecular Dynamics Simulation in NEMS

2011 ◽  
Vol 316-317 ◽  
pp. 107-117
Author(s):  
M. Rizwan Malik ◽  
Tie Lin Shi ◽  
Zi Rong Tang ◽  
Ping Peng
Keyword(s):  
Molecular Dynamics ◽  
Coefficient Of Friction ◽  
Md Simulation ◽  
Three Dimensional ◽  
Rake Angle ◽  
Dynamics Simulation ◽  
Si Substrate ◽  
Embedded Atom ◽  
Thin Film Adhesion ◽  
The Coefficient Of Friction

A growing scientific effort is being devoted to the study of nanoscale interface aspects such as thin-film adhesion, abrasive wear and nanofriction at surfaces by using the nanoscratching technique but there remain immense challenges. In this paper, a three-dimensional (3D) model is suggested for the molecular dynamics (MD) simulation and experimental verification of nanoscratching initiated from nano-indentation, carried out using atomic force microscope (AFM) indenters on Al-film/Si-substrate systems. Hybrid potentials such as Morse and Tersoff, and embedded atom methods (EAM) are taken into account together for the first time in this MD simulation (for three scratching conditions: e.g. orientation, depth and speed, and the relationship between forces and related parameters) in order to determine the mechanisms of nanoscratching phenomena. Salient features such as nanoscratching velocity, direction and depth - as well as indenter shape- and size-dependent functions such as scratch hardness, wear and coefficient of friction - are also examined. A remarkable conclusion is that the coefficient of friction clearly depends upon the tool rake-angle and therefore increases sharply for a large negative angle.

Determination of the Minimum Depth of Cut in Nanometric Machining Using Molecular Dynamics Simulation

2012 ◽  
Vol 565 ◽  
pp. 570-575
Author(s):  
Akinjide Oluwajobi ◽  
Xun Chen
Keyword(s):  
Molecular Dynamics ◽  
Md Simulation ◽  
Chip Thickness ◽  
Dynamics Simulation ◽  
Depth Of Cut ◽  
Limiting Factor ◽  
Nanometric Machining ◽  
Minimum Depth ◽  
Achievable Accuracy

The Minimum Depth of Cut (MDC) is a major limiting factor on achievable accuracy in nanomachining, because the generated surface roughness is primarily attributed to the ploughing process when the uncut chip thickness is less than the MDC. This paper presents an evaluation of a cutting process where a sharp diamond tool with an edge radius of few atoms acts on a crystalline copper workpiece. The molecular dynamics (MD) simulation results show the phenomena of rubbing, ploughing and cutting. The formation of chip occurred from the depth of cut thickness of 1-1.5nm.

Experimental Study on Chip Shape and Tool Wear of High-Speed and Micro-Feed Cutting

2010 ◽  
Vol 431-432 ◽  
pp. 479-482
Author(s):  
Dao Chun Xu ◽  
Ping Fa Feng ◽  
Ding Wen Yu ◽  
Zhi Jun Wu
Keyword(s):  
Tool Wear ◽  
Feed Rate ◽  
High Speed ◽  
Flank Wear ◽  
Chip Thickness ◽  
Friction Angle ◽  
Rake Angle ◽  
Cutting Edge ◽  
Effective Rake Angle ◽  
On Chip

With increasing spindle speed the cutting will be easy to enter into micro-feed cutting region. In the paper, the chip thickness and shape of high-speed and micro-feed cutting was researched in orthogonal milling. The cutting times in different fz was analyzed. We calculate the effective rake angle, friction angle and shear angle Furthermore, we measure cutting edge arc wear and tool flank wear of micro-feed cutting. Shown as the research results, the phenomenon of empty cutting and pure extrusion is very obvious as the feed rate per tooth is lower than 0.011mm/z. As the feed rate per tooth is lower than 0.005mm/z, the tool wear form is mainly cutting edge arc wear. As fz achieves 0.015mm/z, tool wear will decrease obviously and the tool appears the self-sharpening phenomenon.

Molecular Dynamics Simulation of Nanometric Machining Under Realistic Cutting Conditions

2008 ◽  
Author(s):  
R. Promyoo ◽  
H. El-Mounayri ◽  
X. Yang
Keyword(s):  
Molecular Dynamics ◽  
Cutting Force ◽  
Chip Formation ◽  
Thrust Force ◽  
Cutting Speed ◽  
Md Simulations ◽  
Rake Angle ◽  
Dynamics Simulation ◽  
Depth Of Cut ◽  
Nanometric Machining

Molecular Dynamics (MD) simulations of nanometric machining of single-crystal copper were conducted at a conventional cutting speed (5m/s) and different depths of cut (0.724 – 2.172 nm). The simulations were carried out to predict cutting forces and investigate the mechanism of chip formation at the nano level. The effect of tool rake angles and depths of cut on the mechanism of chip formation were also investigated. Tools with different rake angles, namely 0°, 5°, 10°, 15°, 30°, and 45°, were used. It was found that the cutting force, thrust force, and the ratio of the thrust force to cutting force decrease with increasing rake angle. However, the ratio of the thrust force to the cutting force is found to be independent of the depth of cut.

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