scholarly journals Molecular Dynamics Study of the Effect of Abrasive Grains Orientation and Spacing during Nanogrinding

Micromachines ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 712
Author(s):  
Nikolaos E. Karkalos ◽  
Angelos P. Markopoulos
Keyword(s):  
Molecular Dynamics ◽  
Chip Formation ◽  
Material Removal ◽  
Flat Surface ◽  
Ground Surface ◽  
Rake Angle ◽  
Dynamics Model ◽  
Grinding Forces ◽  
Abrasive Grains ◽  
Time Chip

Grinding at the nanometric level can be efficiently employed for the creation of surfaces with ultrahigh precision by removing a few atomic layers from the substrate. However, since measurements at this level are rather difficult, numerical investigation can be conducted in order to reveal the mechanisms of material removal during nanogrinding. In the present study, a Molecular Dynamics model with multiple abrasive grains is developed in order to determine the effect of spacing between the adjacent rows of abrasive grains and the effect of the rake angle of the abrasive grains on the grinding forces and temperatures, ground surface, and chip formation and also, subsurface damage of the substrate. Findings indicate that nanogrinding with abrasive grains situated in adjacent rows with spacing of 1 Å leads directly to a flat surface and the amount of material remaining between the rows of grains remains minimal for spacing values up to 5 Å. Moreover, higher negative rake angle of the grains leads to higher grinding forces and friction coefficient values over 1.0 for angles larger than −40°. At the same time, chip formation is suppressed and plastic deformation increases with larger negative rake angles, due to higher compressive action of the abrasive grains.

scholarly journals Molecular dynamics simulation of multi-pass nano-grinding process

2018 ◽  
Vol 178 ◽  
pp. 03016
Author(s):  
Nikolaos E. Karkalos ◽  
Angelos P. Markopoulos
Keyword(s):  
Molecular Dynamics ◽  
Material Removal ◽  
Cutting Tools ◽  
Md Simulations ◽  
Dynamics Simulation ◽  
Grinding Process ◽  
Grinding Forces ◽  
Workpiece Surface ◽  
Abrasive Grains ◽  
Quality Surface

Grinding involves the use of a large number of micrometric abrasive grains in order to remove material from workpiece surface efficiently and finally render a high quality surface. More specifically, grinding in the nano-metric level serves for attaining nano-level surface quality by removing several layers of atoms from the workpiece surface. The abrasive grains act as individual cutting tools, performing primarily material removal but also induce alterations in the subsurface regions. In order to study the nano-grinding process, Molecular Dynamics (MD) method is particularly capable to provide comprehensive observations of the process and its outcome. In this study, MD simulations of multi-pass grinding for copper substrates, using two abrasive grains, are performed. After the simulations are carried out, results concerning grinding forces and temperatures are presented and discussed.

Molecular Dynamics Study of Abrasive Grain Morphology and Orientation in Nanometric Grinding

2016 ◽  
Vol 686 ◽  
pp. 7-12 ◽  
Author(s):  
Angelos P. Markopoulos ◽  
Nikolaos E. Karkalos ◽  
Dimitrios E. Manolakos
Keyword(s):  
Molecular Dynamics ◽  
Grain Morphology ◽  
Rake Angle ◽  
Depth Of Cut ◽  
Grinding Forces ◽  
Abrasive Grain ◽  
Proposed Model ◽  
On Chip ◽  
Diamond Grain ◽  
Dynamics Method

A simulation of the material removal by a single abrasive grain in nanometric grinding is presented in this paper. Molecular Dynamics method is used for modeling the diamond grain and the copper workpiece. The Morse potential function is used to simulate the interactions between the atoms involved in the procedure. The abrasive grain follows a trajectory with decreasing depth of cut within the workpiece to simulate the interaction of the grain with the workpiece. The influence of the grain shape, being either square or rectangular, and of the orientation of the grain, where the grain has rake angle 10o, -10o and-20o, are studied. From the analysis it is apparent that both grain morphology and orientation play a significant role on chip formation, grinding forces and temperatures. With the appropriate modifications, the proposed model can be used for the simulation of various nanomachining processes and operations, in which continuum mechanics cannot be applied or experimental techniques are subjected to limitations.

Comparative Study on the Materials Removal Mechanism of Ceramics and Steels

2008 ◽  
Vol 389-390 ◽  
pp. 18-23
Author(s):  
Jian Qiang Guo ◽  
Hitoshi Ohmori ◽  
Kazutoshi Katahira ◽  
Yoshihiro Uehara
Keyword(s):  
Comparative Study ◽  
Material Removal ◽  
Ground Surface ◽  
Removal Mechanism ◽  
Material Removal Mechanism ◽  
Grinding Forces ◽  
Dressing Method ◽  
The Difference ◽  
Induced Defects

Ceramics has many advantages that cannot be substituted by metals, but its machining induced defects, such as crack and crater, are the obstacle of using ceramics in engineering. Thus, the further studies on the materials removal mechanism of ceramics should be done. As known, the cutting theory of metals is very successful and it is helpful to understand the material removal mechanism of ceramics. Through doing comparative experiments, the material removal mechanism of ceramics may be more deeply ascertained. Four types of material, such as ZrO2, SiC, STAVAX and SKD11, were ground by ELID (ELectrolytic In-process Dressing) method in this study. The grinding forces, roughness and topography of the ground surface were investigated. On the basis of this experiment, the difference of material removal mechanism between ceramics and steels was explained.

Force and Energy in Grinding Zirconia Ceramics by Brazed Monolayered Diamond Wheels

2011 ◽  
Vol 487 ◽  
pp. 80-83
Author(s):  
Shu Sheng Li ◽  
Jiu Hua Xu ◽  
Y.C. Fu ◽  
H.J. Xu
Keyword(s):  
Material Removal ◽  
Chip Thickness ◽  
Ground Surface ◽  
Morphological Features ◽  
Removal Mechanism ◽  
Zirconia Ceramics ◽  
Grinding Forces ◽  
Thickness Change ◽  
Material Removal Mechanisms ◽  
Removal Mechanisms

An investigation was undertaken to explore the grinding energy and removal mechanisms in grinding zirconia by using brazed diamond wheels. The grinding forces were measured and the morphological features of ground workpiece surfaces were examined. The results indicate that material removal mechanisms are dominated by the combined removal modes of brittle and ductile. The prevailing removal mechanism for the ground surface of zirconia changes from brittle to ductile when the maximum chip thickness change from large to small.

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.

Microgrinding of Nanostructured Carbide Coatings: Ground Surface and Subsurface Damage Observations

2006 ◽  
Vol 304-305 ◽  
pp. 276-280 ◽  
Author(s):  
Y.H. Ren ◽  
Zhi Xiong Zhou ◽  
Zhao Hui Deng
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Material Removal ◽  
Ground Surface ◽  
Subsurface Damage ◽  
Removal Mechanism ◽  
Material Removal Mechanism ◽  
Carbide Coatings ◽  
Subsurface Layers ◽  
Scanning Electron

Surface microgrinding of the nanostructured WC/12Co coatings have been undertaken with diamond wheels under various conditions. Nondestructive and destructive approaches were utilized to assess damage in ground nanostructured coatings. Different surface and subsurface configurations were observed by scanning electron microscopy. This paper investigates the effects of microgrinding conditions on damage formation in the surface and subsurface layers of the ground nanostructured WC/12Co coatings. And the material-removal mechanism has been discussed.

scholarly journals Performance of Norton Quantum Grinding Wheels

2016 ◽  
Vol 686 ◽  
pp. 125-130 ◽  
Author(s):  
Miroslav Neslušan ◽  
Jitka Baďurová ◽  
Anna Mičietová ◽  
Maria Čiliková
Keyword(s):  
Surface Roughness ◽  
Ground Surface ◽  
Bearing Steel ◽  
Grinding Wheel ◽  
Grinding Wheels ◽  
Grinding Forces ◽  
Removal Rates ◽  
Surface Burn ◽  
Conventional Grinding

This paper deals with cutting ability of progressive Norton Quantum grinding wheel during grinding roll bearing steel 100Cr6 of hardness 61 HRC. Cutting ability of this wheel is compared with conventional grinding wheel and based on measurement of grinding forces as well as surface roughness. Results of experiments show that Norton Quantum grinding wheels are capable of long term grinding cycles at high removal rates without unacceptable occurrence of grinding chatter and surface burn whereas application of conventional wheel can produce excessive vibration and remarkable temper colouring of ground surface. Moreover, while Norton Quantum grinding wheel gives nearly constant grinding forces and surface roughness within ground length at higher removal rates, conventional grinding wheel (as that reported in this study) does not.

Molecular Dynamics Modeling the Nano-Identation of Titanium

2021 ◽  
Author(s):  
Peiqiang Yang ◽  
Xueping Zhang ◽  
Zhenqiang Yao ◽  
Rajiv Shivpuri
Keyword(s):  
Molecular Dynamics ◽  
Plastic Deformation ◽  
Titanium Alloys ◽  
Large Scale ◽  
Mechanical Response ◽  
Pure Titanium ◽  
Dynamics Modeling ◽  
Dynamics Model ◽  
Nano Indentation ◽  
Molecular Dynamics Modeling

Abstract Titanium alloys’ excellent mechanical and physical properties make it the most popular material widely used in aerospace, medical, nuclear and other significant industries. The study of titanium alloys mainly focused on the macroscopic mechanical mechanism. However, very few researches addressed the nanostructure of titanium alloys and its mechanical response in Nano-machining due to the difficulty to perform and characterize nano-machining experiment. Compared with nano-machining, nano-indentation is easier to characterize the microscopic plasticity of titanium alloys. This research presents a nano-indentation molecular dynamics model in titanium to address its microstructure alteration, plastic deformation and other mechanical response at the atomistic scale. Based on the molecular dynamics model, a complete nano-indentation cycle, including the loading and unloading stages, is performed by applying Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS). The plastic deformation mechanism of nano-indentation of titanium with a rigid diamond ball tip was studied under different indentation velocities. At the same time, the influence of different environment temperatures on the nano-plastic deformation of titanium is analyzed under the condition of constant indentation velocity. The simulation results show that the Young’s modulus of pure titanium calculated based on nano-indentation is about 110GPa, which is very close to the experimental results. The results also show that the mechanical behavior of titanium can be divided into three stages: elastic stage, yield stage and plastic stage during the nano-indentation process. In addition, indentation speed has influence on phase transitions and nucleation of dislocations in the range of 0.1–1.0 Å/ps.

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