Tool/Chip Interfacial Stress Distributions in Atomistic Machining of Polycrystalline Coppers

2014 ◽  
Author(s):  
Chunhui Ji ◽  
Jing Shi ◽  
Yachao Wang ◽  
Hsueh-Ming Steve Wang
Keyword(s):  
Grain Size ◽  
Friction Force ◽  
Normal Force ◽  
Three Dimensional ◽  
Cutting Speed ◽  
Interfacial Stress ◽  
Depth Of Cut ◽  
Polycrystalline Copper ◽  
Stress Distributions ◽  
Normal Forces

A three-dimensional molecular dynamics (MD) model is developed to study the tool/chip interface stress distributions in machining of polycrystalline copper at atomistic scale. Three polycrystalline copper structures with equivalent grain sizes of 12.25, 7.72, and 6.26 nm are constructed for simulation. Also, a monocrystalline copper structure of the same dimension is simulated as the benchmark case. In addition to the grain size, the effects of depth of cut and cutting speed are also considered. The friction force and normal force profiles along the tool/chip interface in both polycrystalline and monocrystalline nano-machining exhibit similar patterns. The reduction in grain size overall increases the magnitude of normal force along the tool/chip interface, but the normal forces in all polycrystalline cases are still smaller than that in the monocrystalline case. In polycrystalline nano-machining, the increase of depth of cut consistently increases the normal force along the entire contact area, but this trend cannot be observed for the friction force. In addition, the stress profiles are also significantly affected by the cutting speed.

Tool/Chip Interfacial Friction Analysis in Atomistic Machining of Polycrystalline Coppers

2014 ◽  
Vol 2 (4) ◽  
Author(s):  
Jing Shi ◽  
Chunhui Ji ◽  
Yachao Wang ◽  
Steve Hsueh-Ming Wang
Keyword(s):  
Grain Size ◽  
Friction Force ◽  
Normal Force ◽  
Three Dimensional ◽  
Cutting Speed ◽  
Rake Angle ◽  
Depth Of Cut ◽  
Polycrystalline Copper ◽  
Friction Forces ◽  
Force Components

Three-dimensional (3D) molecular dynamics (MD) simulation is performed to study the tool/chip interface friction phenomenon in machining of polycrystalline copper at atomistic scale. Three polycrystalline copper structures with the equivalent grain sizes of 12.25, 7.72, and 6.26 nm are constructed for simulation. Also, a monocrystalline copper structure is simulated as the benchmark case. Besides the grain size, the effects of depth of cut, cutting speed, and tool rake angle are also considered. It is found that the friction force and normal force distributions along the tool/chip interface in both polycrystalline and monocrystalline machining exhibit similar patterns. The reduction in grain size overall increases the magnitude of normal force along the tool/chip interface, but the normal forces in all polycrystalline cases are smaller than that in the monocrystalline case. In atomistic machining of polycrystalline coppers, the increase of depth of cut consistently increases the normal force along the entire contact area, but this trend cannot be observed for the friction force. In addition, both higher cutting speed and more negative tool rake angle do not bring significant changes to the distributions of normal and friction forces on the interface, but both factors tend to increase the magnitudes of the two force components.

Green-State Micromilling of Additive Manufactured AISI316 L

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Sandeep Kuriakose ◽  
Paolo Parenti ◽  
Salvatore Cataldo ◽  
Massimiliano Annoni
Keyword(s):  
Surface Roughness ◽  
Surface Quality ◽  
Surface Defects ◽  
Three Dimensional ◽  
Cutting Speed ◽  
Force Sensor ◽  
Depth Of Cut ◽  
Green State ◽  
Air Supply ◽  
Wide Range

Additive manufacturing (AM) of metal offers matchless design sovereignty to manufacture metallic microcomponents from a wide range of materials. Green-state micromilling is a promising method that can be integrated into the AM of metallic feedstock microcomponents in typical extrusion-based AM methods for compensating the inability to generate microfeatures. The integration enables the manufacturing of complex geometries, the generation of good surface quality, and can provide exceptional flexibility to new product shapes. This work is a micromachinability study of AISI316 L feedstock components produced by extrusion-based AM where the effects of workpiece temperature and the typical micromilling parameters such as cutting speed, feed per tooth, axial depth of cut, and air supply are studied. Edge integrity and surface roughness of the machined slots, as well as cutting forces, are analyzed using three-dimensional microscopy and piezoelectric force sensor, respectively. Green-state micromilling results were satisfying with good produced quality. The micromilling of heated workpieces (45 °C), with external air supply for debris removal, showed the best surface quality with surface roughness values that reached around Sa = 1.5 μm, much smaller than the average metal particles size. Minimum tendency to borders breakage was showed but in some cases microcutting was responsible of the generation of surface defects imputable to lack of adhesion of deposited layers. Despite this fact, the integrability of micromilling into extrusion-based AM cycles of metallic feedstock is confirmed.

Surface integrity in laser-assisted machining of Ti6Al4V

2020 ◽  
pp. 095440622097825
Author(s):  
O Kalantari ◽  
MM Fallah ◽  
F Jafarian ◽  
SR Hamzeloo
Keyword(s):  
Surface Roughness ◽  
Grain Size ◽  
Surface Integrity ◽  
Cutting Tool ◽  
Cutting Temperature ◽  
Cutting Speed ◽  
Laser Source ◽  
Depth Of Cut ◽  
Thermal Source ◽  
Laser Assisted Machining

In laser-assisted machining (LAM), the laser source is focused on the workpiece as a thermal source and locally increases the workpiece temperature and makes the material soft ahead of the cutting tool so using this method, the machining forces are reduced, which causes improving the surface quality and cutting tool life. Machinability of advanced hard materials is significantly low and conventional methods do not work effectively. Therefore, utilizing an advanced method is inevitable. The product life and performance of complex parts of the leading industry depends on surface integrity. In this work, the surface integrity features including microhardness, grain size and surface roughness (Ra) and also the maximum cutting temperature were investigated experimentally in LAM of Ti-6Al-4V. According to the results, cutting speed has inverse effect on the effectiveness of LAM process because with increasing speed (15 to 63 m/min), temperature decreases (524 °C to 359 °C) and surface roughness increases (0.57 to 0.71 μm). Enhancing depth of cut and feed has direct effect on the process temperature, grain size, microhardness and surface roughness.

scholarly journals Molecular Dynamics Simulation of Nanoscale Abrasive Wear of Polycrystalline Silicon

Crystals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 463 ◽  
Author(s):  
Pengzhe Zhu ◽  
Rui Li ◽  
Hanyu Gong
Keyword(s):  
Molecular Dynamics ◽  
Grain Size ◽  
Size Effect ◽  
Friction Force ◽  
Polycrystalline Silicon ◽  
Normal Force ◽  
Crystalline Silicon ◽  
Grain Size Effect ◽  
Single Crystalline Silicon ◽  
Nanoscale Wear

In this work, molecular dynamics simulations of the nanoscratching of polycrystalline and singlecrystalline silicon substrates using a single-crystal diamond tool are conducted to investigate the grain size effect on the nanoscale wear process of polycrystalline silicon. We find that for a constant indentation depth, both the average normal force and friction force are much larger for single-crystalline silicon compared to polycrystalline silicon. It is also found that, for the polycrystalline substrates, both the average normal force and friction force increase with increasing grain size. However, the friction coefficient decreases with increasing grain size, and is the smallest for single-crystalline silicon. We also find that the quantity of wear atoms increases nonlinearly with the average normal load, inconsistent with Archard’s law. The quantity of wear atoms is smaller for polycrystalline substrates with a larger average grain size. The grain size effect in the nanoscale wear can be attributed to the fact that grain boundaries contribute to the plastic deformation of polycrystalline silicon.

Characteristics of Abrasive Waterjet Generated Surfaces and Effects of Cutting Parameters and Structure Vibration

1995 ◽  
Vol 117 (4) ◽  
pp. 516-525 ◽  
Author(s):  
J. Chao ◽  
G. Zhou ◽  
M. C. Leu ◽  
E. Geskin
Keyword(s):  
Three Dimensional ◽  
Cutting Speed ◽  
Cutting Parameters ◽  
Abrasive Waterjet ◽  
Depth Of Cut ◽  
Height Distribution ◽  
Waterjet Machining ◽  
Machining System ◽  
Structure Vibration ◽  
Abrasive Size

We use three-dimensional surface topography analysis for evaluating waterjet generated surfaces. The waterjet generated surface is separated into smooth and striation zones, where striation influence is negligible in the smooth zone. It is found that the smooth zone has a random, moderately isotropic texture, with the height distribution nearly Gaussian. The effects of cutting speed, depth of cut, and abrasive size on the surface roughness are studied for the smooth zone and striation zone separately. This provides useful information for controlling process parameters to obtain smooth finished surfaces. Spectral analysis is used to investigate the surface striation and machine structure vibration. It is found that forced vibration of the mechanical structure strongly influences striations generated in the waterjet machining system.

Three-dimensional finite element modeling of effect on the cutting forces of rake angle and approach angle in milling

2016 ◽  
Vol 231 (2) ◽  
pp. 83-88 ◽  
Author(s):  
Kadir Gok ◽  
Hüseyin Sari ◽  
Arif Gok ◽  
Süleyman Neseli ◽  
Erol Turkes ◽  
...  
Keyword(s):  
Cutting Tools ◽  
Three Dimensional ◽  
Cutting Speed ◽  
Cutting Parameters ◽  
Rake Angle ◽  
Depth Of Cut ◽  
Dry Cutting ◽  
Milling Operations ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

In this study, milling operations were carried out using AISI 1040 specimens steel in dry cutting conditions. The cutting tools used in the experiment include P20 tool steel and they also have three different approach angles (45°, 60°, 75°) and rake angles (0°, −6°, −12°). In milling experiments, cutting parameters with a depth of cut of 1.5 mm, cutting speed of 193 m/min, and feed rate of 313 mm/min were selected. A comparison was presented between the force values which were obtained by measured value and predicted with numerical simulations, and then a good agreement was found between measured and predicted force values. As result of, it was observed that the rake and approach angles were effective in milling operations.

A Three-Dimensional, Tool-Life Equation—Machining Economics

1959 ◽  
Vol 81 (3) ◽  
pp. 239-249 ◽  
Author(s):  
Bertil N. Colding
Keyword(s):  
Tool Life ◽  
Three Dimensional ◽  
Cutting Speed ◽  
Minimum Cost ◽  
Optimum Combination ◽  
Depth Of Cut ◽  
Nose Radius ◽  
Edge Angle ◽  
Machining Economics ◽  
General Tool

In Part 1 of this paper, two tool-life equations are derived, one limited equation and one general tool-life equation, between the variables cutting speed, chip equivalent, and tool life. The chip equivalent, introduced by Woxén, is a well-defined function of feed, depth of cut, nose radius, and side-cutting-edge angle. The limited equation takes into account the variation of Taylor’s exponent n with the value of the chip equivalent, but the equation is only valid within certain limits of cutting speed and chip equivalent. A general equation is then derived on the basis of the limited equation. In Part 2 an expression called the productivity is derived. This relationship is valid for either maximum production or minimum cost and, combined with the general, hyperbolic, tool-life equation, it is used to investigate the optimum combination of tool-life, cutting speed, and chip equivalent.

scholarly journals Effect of Subsurface Microstructures on Adhesion of Highly Confined Elastic Films

2020 ◽  
Vol 88 (3) ◽  
Author(s):  
Manar Samri ◽  
Attila Kossa ◽  
René Hensel
Keyword(s):  
Poisson’S Ratio ◽  
Contact Stiffness ◽  
Three Dimensional ◽  
Adhesive Layer ◽  
Interfacial Stress ◽  
Poisson's Ratio ◽  
Stress Distributions ◽  
Elastic Film ◽  
Polymer Adhesive ◽  
The Impact

Abstract Polymer adhesive films sandwiched between two rigid solids are a common bonding strategy. The mechanics and consequently the adhesion of such geometrically confined films depend mainly on their thickness, Young's modulus, and the Poisson's ratio of the material. In this work, we explore the effect of a micropatterned subsurface embedded into the adhesive layer. We compare experiments with three-dimensional numerical simulations to evaluate the impact of the microstructure on the contact stiffness and effective modulus. The results are used to extend a previously proposed size scaling argument on adhesion from incompressible to slightly compressible films to account for the silicone used in our study with a Poisson's ratio of 0.495. In addition, interfacial stress distributions between the elastic film and the glass disc are obtained from plane strain simulations to evaluate characteristic adhesion failures such as edge cracks and cavitation. Overall, the micropatterned subsurface has a large impact on the contact stiffness, the interfacial stress distribution, and the detachment behavior; however, the adhesion performance is only slightly improved in comparison to a non-patterned subsurface.

The influence of friction on the tooth normal force of spur and helical gears

2019 ◽  
Vol 233 (21-22) ◽  
pp. 7391-7400
Author(s):  
T Reimann ◽  
T Herzog ◽  
D Kadach ◽  
K Stahl
Keyword(s):  
Friction Force ◽  
Normal Force ◽  
Load Carrying Capacity ◽  
Helical Gears ◽  
Gear Mesh ◽  
Normal Forces ◽  
Cylindrical Gears ◽  
Load Carrying ◽  
Set Up ◽  
Tooth Flank

The tooth normal force is one of the main influencing factors for calculating the pitting load-carrying capacity of gears. In the current standards for cylindrical gears, it is calculated without regard to the friction force’s influence. This paper presents a simple local calculation approach for determining the friction force and driving direction’s influence on the tooth normal force of cylindrical gears on the whole tooth flank. Unlike previous models, without the need to set up a dynamic model of the gear mesh and having to solve differential equations numerically. For two exemplary spur and one helical gear set, the tooth normal forces are calculated considering the friction force and the driving direction’s influence and without regard to these effects. A comparison is carried out and the results are discussed thoroughly.

Forced Vibration of an Initial Stressed Rectangular Composite Thick Plate With a Cylindrical Hole

2009 ◽  
Author(s):  
Nazmiye Yahnioglu ◽  
Ulku Babuscu Yesil
Keyword(s):  
Thick Plate ◽  
Three Dimensional ◽  
Problem Formulation ◽  
Cylindrical Hole ◽  
Stress Distributions ◽  
Normal Forces ◽  
Time Harmonic ◽  
Upper Face ◽  
Linearized Theory ◽  
Dynamic Time

Within the framework of the Three-Dimensional Linearized Theory of Elastic Waves in Initially Stressed Bodies, the influence is studied of the initial stretching of a composite thick plate containing a cylindrical hole on the stress concentration around a hole caused by the action of the additional uniformly distributed dynamic (time-harmonic) normal forces on the upper face of the plane. The corresponding problem formulation is presented and, in order to find the solution to this problem, the finite element method is employed. The numerical results on the concentration of the stress around the hole and the influence of the initial stretching on this concentration are presented. According to these results, in particular it is established that the stress distributions around the cylindrical hole changed significantly with the initial stretching force.

Sign in / Sign up

Export Citation Format

Share Document