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.

Investigation of tool geometry in nanoscale cutting single-crystal copper by molecular dynamics simulation

2019 ◽  
Vol 233 (8) ◽  
pp. 1208-1220 ◽  
Author(s):  
Houfu Dai ◽  
Hao Du ◽  
Jianbin Chen ◽  
Genyu Chen
Keyword(s):  
Molecular Dynamics ◽  
Single Crystal ◽  
Cutting Force ◽  
Rake Angle ◽  
Tool Geometry ◽  
Single Crystal Copper ◽  
Clearance Angle ◽  
Edge Radius ◽  
Lower Temperature ◽  
Nanoscale Cutting

Molecular dynamics has been employed in this paper to investigate the nanoscale cutting process of single-crystal copper with a diamond tool. The behavior of the workpiece during material removal by diamond cutting has been studied. The effects of tool geometry including rake angle, clearance angle, and edge radius are thoroughly investigated in terms of chips, dislocation movement, temperature distribution, cutting temperature, cutting force, and friction coefficient. The investigation showed that an appropriate positive rake angle ([Formula: see text]), a suitable clearance angle ([Formula: see text]), or a smaller edge radius tip resulted in a smaller cutting force and a better subsurface finish. It was found that a tool with a rake angle of [Formula: see text] generated more chips, had a higher cutting efficiency, and produced a lower temperature in the workpiece, but a smaller rake angle tip was more conducive to protecting the groove compared to a large rake angle tip. Compared with a tool with a small clearance angle, the tool with a larger clearance angle generated more chips and caused a lower temperature rise in the copper workpiece, and prolonged its lifetime. In addition, a larger clearance angle tip was more conducive to protecting the groove. A smaller edge radius tip reduces the cutting heat during the nanoscale cutting process, while the volume of chips decreases. These results indicated that it is possible to control and adjust the tool parameters according to the tool rake angle, clearance angle, and edge radius during the machining of single-crystal copper, and a set of tool parameters were obtained: [Formula: see text] rake angle, [Formula: see text] clearance angle, and 0 nm edge radius which could reduce surface damage and the required cutting force.

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.

Micro Flat End Milling Simulation Model With Instantaneous Plowing Area Prediction

2016 ◽  
Vol 4 (2) ◽  
Author(s):  
Abdolreza Bayesteh ◽  
Junghyuk Ko ◽  
Martin Byung-Guk Jun
Keyword(s):  
Feed Rate ◽  
Tool Path ◽  
End Milling ◽  
Chip Thickness ◽  
Depth Of Cut ◽  
Uncut Chip Thickness ◽  
Chip Area ◽  
Edge Radius ◽  
Wide Range ◽  
Radial Depth

There is an increasing demand for product miniaturization and parts with features as low as few microns. Micromilling is one of the promising methods to fabricate miniature parts in a wide range of sectors including biomedical, electronic, and aerospace. Due to the large edge radius relative to uncut chip thickness, plowing is a dominant cutting mechanism in micromilling for low feed rates and has adverse effects on the surface quality, and thus, for a given tool path, it is important to be able to predict the amount of plowing. This paper presents a new method to calculate plowing volume for a given tool path in micromilling. For an incremental feed rate movement of a micro end mill along a given tool path, the uncut chip thickness at a given feed rate is determined, and based on the minimum chip thickness value compared to the uncut chip thickness, the areas of plowing and shearing are calculated. The workpiece is represented by a dual-Dexel model, and the simulation properties are initialized with real cutting parameters. During real-time simulation, the plowed volume is calculated using the algorithm developed. The simulated chip area results are qualitatively compared with measured resultant forces for verification of the model and using the model, effects of cutting conditions such as feed rate, edge radius, and radial depth of cut on the amount of shearing and plowing are investigated.

Investigation on Mechanism of Ultra-Smoothed Surface with a Micro Slot on the Flank Face in Micro Cutting

2014 ◽  
Vol 651-653 ◽  
pp. 764-767
Author(s):  
Tao Zhang ◽  
Hou Jun Qi ◽  
Gen Li
Keyword(s):  
Surface Roughness ◽  
Chip Thickness ◽  
Cutting Edge ◽  
Back Side ◽  
Uncut Chip Thickness ◽  
Micro Cutting ◽  
Cutting Edge Radius ◽  
Edge Radius ◽  
Flank Face ◽  
Side Flow

Micro cutting is a promising manufacturing method to obtain good surface integrity. Surface roughness shows size effect when the uncut chip thickness is smaller than the cutting edge radius. A special micro slot on the flank face of cutting tools was manufactured with discharge. Two groups of micro orthogonal cutting were conducted. The surface roughness of machined surface was measured and compared to each other. The results show that surface roughness decreases first and then increases with the ratio of uncut chip thickness to cutting edge radius. The surface machined with micro slot is better than that of without micro slot due to the micro slot restrain the back side flow of work piece based on the finite element model.

Size Effects in Cutting With a Diamond-Coated Tool

2011 ◽  
Author(s):  
Feng Qin ◽  
Xibing Gong ◽  
Kevin Chou
Keyword(s):  
Residual Stresses ◽  
Size Effect ◽  
Normal Stress ◽  
High Speed ◽  
Chip Thickness ◽  
Tool Geometry ◽  
Uncut Chip Thickness ◽  
Edge Radius ◽  
Coated Tool ◽  
Tool Stresses

In machining using a diamond-coated tool, the tool geometry and process parameters have compound effects on the thermal and mechanical states in the tools. For example, decreasing the edge radius tends to increase deposition-induced residual stresses at the tool edge interface. Moreover, changing the uncut chip thickness to a small-value range, comparable or smaller than the edge radius, will involve the so-called size effect. In this study, a developed 2D cutting simulation that incorporates deposition residual stresses was applied to evaluate the size effect, at different cutting speeds, on the tool stresses, tool temperatures, specific cutting energy as well as the interface stresses around a cutting edge. The size effect on the radial normal stress is more noticeable at a low speed. In particular, a large uncut chip thickness has a substantially lower stress. On the other hand, the size effect on the circumferential normal stress is more noticeable at a high speed. At a small uncut chip thickness, the stress is largely compressive.

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]

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.

Influence of Reground Tool Sharpness on Micro-Cutting Process

2010 ◽  
Vol 37-38 ◽  
pp. 550-553
Author(s):  
Xin Li Tian ◽  
Zhao Li ◽  
Xiu Jian Tang ◽  
Fang Guo ◽  
Ai Bing Yu
Keyword(s):  
Cutting Forces ◽  
Orthogonal Cutting ◽  
Cutting Tools ◽  
Chip Thickness ◽  
Cutting Edge ◽  
Cutting Process ◽  
Micro Cutting ◽  
Temperature Distributions ◽  
Edge Radius ◽  
1045 Steel

Tool edge radius has obvious influences on micro-cutting process. It considers the ratio of the cutting edge radius and the uncut chip thickness as the relative tool sharpness (RST). FEM simulations of orthogonal cutting processes were studied with dynamics explicit ALE method. AISI 1045 steel was chosen for workpiece, and cemented carbide was chosen for cutting tool. Sixteen cutting edges with different RTS values were chosen for analysis. Cutting forces and temperature distributions were calculated for carbide cutting tools with these RTS values. Cutting edge with a small RTS obtains large cutting forces. Ploughing force tend to sharply increase when the RTS of the cutting edge is small. Cutting edge with a reasonable RTS reduces the heat generation and presents reasonable temperature distributions, which is beneficial to cutting life. The force and temperature distributions demonstrate that there is a reasonable RTS range for the cutting edge.

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.

scholarly journals Cutting-based single atomic layer removal mechanism of monocrystalline copper: edge radius effect

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Wenkun Xie ◽  
Fengzhou Fang
Keyword(s):  
Material Removal ◽  
Chip Thickness ◽  
Atomic Layer ◽  
Atomic Scale ◽  
Removal Mechanism ◽  
Minimum Chip Thickness ◽  
Layer Removal ◽  
Edge Radius ◽  
Mechanical Cutting ◽  
Cutting Model

AbstractThe ultimate objective of mechanical cutting is to down minimum chip thickness to single atomic layer. In this study, the cutting-based single atomic layer removal mechanism on monocrystalline copper is investigated by a series of molecular dynamics analysis. The research findings report that when cutting depth decreases to atomic scale, minimum chip thickness could be down to single atomic layer by mechanical cutting using rounded edge tool. The material removal behaviour during cutting-based single atomic layer removal exhibits four characteristics, including chip formation by shearing-stress driven dislocation motion, elastic deformation on the processed surface, atomic sizing effect, and cutting-edge radius effect. Based on this understanding, a new cutting model is proposed to study the material removal behaviour in cutting-based single atomic layer removal process, significantly different from those for nanocutting and conventional cutting. The outcomes provide theoretical support for the research and development of the atomic and close-to-atomic scale manufacturing technology.

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