Prediction of Temperature and Stress Distribution During Micro-Cutting of Ti-6Al-4V

2007 ◽  
Author(s):  
Dong Lu ◽  
Jianfeng Li ◽  
Yiming Rong ◽  
Jie Sun ◽  
Zhongqiu Wang
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Maximum Shear Stress ◽  
Cutting Temperature ◽  
Cutting Speed ◽  
Chip Thickness ◽  
Machining Process ◽  
Maximum Temperature ◽  
Uncut Chip Thickness ◽  
Micro Cutting

A finite element method (FEM) for predicting the temperature and stress distribution in micro-cutting of Ti-6Al-4V is presented. The flow stress of Ti-6Al-4V is taken as a function of strain, strain rate and temperature in order to reflect realistic behavior in machining process. Diamond cutting tool is used. From simulation, cutting force, thrust force, cutting temperature and distribution of cutting temperature and stress are obtained. The effects of cutting speed and uncut chip thickness on the maximum temperature and maximum shear stress are analyzed and size effect is observed. The simulation results show that in micro-cutting of Ti-6Al-4V the maximum temperature locates on the shear plane. And the maximum shear stress locates on the stick region. The maximum temperature decreases as the uncut chip thickness decreases, and it increases with an increase in cutting speed. The maximum shear stress increases as the uncut chip thickness decreases, and it decreases with an increase in cutting speed.

Study on Temperature Effect in Micro-Cutting Process

2011 ◽  
Vol 268-270 ◽  
pp. 2077-2080
Author(s):  
Zi Yang Cao ◽  
Hua Li
Keyword(s):  
Temperature Effect ◽  
Orthogonal Cutting ◽  
Temperature Drop ◽  
Cutting Temperature ◽  
Cutting Speed ◽  
Chip Thickness ◽  
Cutting Process ◽  
Material Strength ◽  
Uncut Chip Thickness ◽  
Micro Cutting

A coupled thermo-mechanical model is used to simulate two-dimensional orthogonal cutting process based on simulation model of micro-cutting. The temperature effect in micro-cutting process is studied deeply through FEM combined with micro-cutting experiments. The results indicate that cutting temperature decreases at the tool-chip interface with reduction in uncut chip thickness at high cutting speed and large uncut chip thickness. The temperature drop tends to have a hardening effect on the material strength, which in turn causes an increase in the specific cutting energy.

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.

Experimental investigation of a slip-line field model for a worn cutting tool

2013 ◽  
Vol 228 (8) ◽  
pp. 1398-1404 ◽  
Author(s):  
Alper Uysal ◽  
Erhan Altan
Keyword(s):  
Wear Rate ◽  
Slip Line ◽  
Field Model ◽  
Cutting Tool ◽  
Flank Wear ◽  
Cutting Speed ◽  
Chip Thickness ◽  
Rake Angle ◽  
Uncut Chip Thickness ◽  
Line Field

In this study, the slip-line field model developed for orthogonal machining with a worn cutting tool was experimentally investigated. Minimum and maximum values of five slip-line angles ( θ1, θ2, δ2, η and ψ) were calculated. The friction forces that were caused by flank wear land, chip up-curl radii and chip thicknesses were calculated by solving the model. It was specified that the friction force increased with increase in flank wear rate and uncut chip thickness and it decreased a little with increase in cutting speed and rake angle. The chip up-curl radius increased with increase in flank wear rate and it decreased with increase in uncut chip thickness. The chip thickness increased with increase in flank wear rate and uncut chip thickness. Besides, the chip thickness increased with increase in rake angle and it decreased with increase in cutting speed.

scholarly journals Shear Stress Distribution in the Opening Chords of Hybrid R/C T-Beams with Opening

2018 ◽  
Vol 147 ◽  
pp. 01005
Author(s):  
Jonie Tanijaya
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Shear Force ◽  
Maximum Shear Stress ◽  
Shear Stress Distribution ◽  
Shear Stresses ◽  
Web Openings ◽  
The Right ◽  
Lower Corner ◽  
T Beam

This study is carried out to evaluate the potential of three hybrid T-beams with web openings theoretical shear stresses distribution. The shear stresses at the opening edges were plotted at the working stage, yielding stage and collapse stage for these three tested beams. The available experimental results from the previous research was compared to the finite element results as well as the developed analytical. The shear stress distribution at the middle of the top and bottom chords of the opening in pure bending region are zero. At the upper and lower corners of the opening occurs the maximum shear stresses. The maximum shear stress occurs at the right lower corner chord at the high moment edge and at the left upper corner chord at the low moment edge in beams with openings at high shear and high flexural – shear region. Furthermore, an extensive parametric study is performed on these beams to find the distributing ratio of the shear force between the opening chords. The shear force at an opening in hybrid R/C T-beam is carried by the top and bottom chords of the opening according to the area – moment of inertia root ratio with the correction factor 0.70.

Effect of Cutting Temperature on Phase Transformation in Cutting of NiTi Alloy

2020 ◽  
Author(s):  
Hao Yang ◽  
Katsuhiko Sakai ◽  
Hiroo Shizuka ◽  
Kunio Hayakawa ◽  
Tetsuo Nagare
Keyword(s):  
Phase Transformation ◽  
Phase State ◽  
Niti Alloy ◽  
Cutting Temperature ◽  
Cutting Speed ◽  
Cutting Process ◽  
Maximum Temperature ◽  
Machined Surface ◽  
Speed Condition ◽  
Work Material

Abstract In this study, the effect of cutting temperature on phase transformation in cutting of room temperature austenitic NiTi alloy was investigated by X-ray diffraction (XRD) and temperature measurements. Results from XRD reveals that after cutting process, the phase state of work material near the machined surface transformed from austenite to martensite at relatively low cutting speed conditions while the phase state of work material did not undergo any form of transformation at the highest cutting speed condition. Temperature measurement results measured with temperature indicating paint showed that the maximum temperature of work material near the machined surface in cutting process exceeded the Md temperature at the highest cutting speed condition. However, there was no phase transformation observed in cutting chips after cutting at all cutting speed conditions as the temperature of cutting chips was much higher than the Md temperature under all cutting speed conditions.

scholarly journals Chip Morphology and Delamination Characterization for Vibration-Assisted Drilling of Carbon Fiber-Reinforced Polymer

2019 ◽  
Vol 3 (1) ◽  
pp. 23 ◽  
Author(s):  
Ramy Hussein ◽  
Ahmad Sadek ◽  
Mohamed Elbestawi ◽  
M. Attia
Keyword(s):  
Carbon Fiber ◽  
Cutting Temperature ◽  
Cutting Speed ◽  
Chip Thickness ◽  
Chip Morphology ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Carbon Fiber Reinforced Polymers ◽  
Geometrical Accuracy ◽  
Carbon Fiber Reinforced

Carbon fiber-reinforced polymers (CFRP) are widely used in the aerospace industry. A new generation of aircraft is being built using CFRP for up to 50% of their total weight, to achieve higher performance. Exit delamination and surface integrity are significant challenges reported during conventional drilling. Exit delamination influences the mechanical properties of machined parts and, consequently, reduces fatigue life. Vibration-assisted drilling (VAD) has much potential to overcome these challenges. This study is aimed at investigating exit delamination and geometrical accuracy during VAD at both low- and high-frequency ranges. The kinematics of VAD are used to investigate the relationship between the input parameters (cutting speed, feed, vibration frequency, and amplitude) and the uncut chip thickness. Exit delamination and geometrical accuracy are then evaluated in terms of mechanical and thermal load. The results show a 31% reduction in cutting temperature, as well as a significant enhancement in exit delamination, by using the VAD technology.

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.

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]

Internal Stresses in Elastohydrodynamic Lubrication of Rolling/Sliding Contacts

1989 ◽  
Vol 111 (1) ◽  
pp. 180-187 ◽  
Author(s):  
Farshid Sadeghi ◽  
Ping C. Sui
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Internal Stress ◽  
Maximum Shear Stress ◽  
Elastohydrodynamic Lubrication ◽  
Normal Pressure ◽  
Internal Stresses ◽  
Stress Distributions ◽  
Principal Stresses ◽  
Dimensionless Velocity

The internal stress distribution in elastohydrodynamic lubrication of rolling/sliding line contact was obtained. The technique involves the full EHD solution and the use of Lagrangian quadrature to obtain the internal stress distributions in the x, y, z-directions and the shear stress distribution as a function of the normal pressure and the friction force. The principal stresses and the maximum shear stress were calculated for dimensionless loads ranging from (2.0452 × 10−5) to (1.3 × 10−4) and dimensionless velocity of 10−10 to 10−11 for slip ratios ranging from 0 to pure sliding condition.

Evidence of Ductile Tearing Ahead of the Cutting Tool and Modeling the Energy Consumed in Material Separation in Micro-Cutting

2006 ◽  
Vol 129 (2) ◽  
pp. 321-331 ◽  
Author(s):  
Sathyan Subbiah ◽  
Shreyes N. Melkote
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Damage Model ◽  
Chip Thickness ◽  
Element Model ◽  
Uncut Chip Thickness ◽  
Micro Cutting ◽  
Ductile Tearing ◽  
Material Separation ◽  
Cutting Experiments

Orthogonal cutting experiments using a quick-stop device are performed on Al2024-T3 and OFHC copper to study the chip–workpiece interface in a scanning electron microscope. Evidence of ductile tearing ahead of the tool at cutting speeds of 150m∕min has been found. A numerical finite element model is then developed to study the energy consumed in material separation in micro-cutting. The ductile fracture of Al2024-T3 in a complex stress state ahead of the tool is captured using a damage model. Chip formation is simulated via the use of a sacrificial layer and sequential elemental deletion in this layer. Element deletion is enforced when the accumulated damage exceeds a predetermined value. A Johnson–Cook damage model that is load history dependent and with strain-to-fracture dependent on stress, strain rate, and temperature is used to model the damage. The finite element model is validated using the cutting forces obtained from orthogonal micro-cutting experiments. Simulations are performed over a range of uncut chip thickness values. It is found that at lower uncut chip thickness values, the percentage of energy expended in material separation is higher than at higher uncut chip thicknesses. This work highlights the importance of the energy associated with material separation in the nonlinear scaling effect of specific cutting energy in micro-cutting.

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