3D Heat Transfer Analysis for a Hybrid Approach to Predict Residual Stresses After Ball-End Milling

In the direct digital metal manufacturing, Electron Beam Additive Manufacturing (EBAM) has been used to fabricate sophisticated metallic parts, in a layer by layer fashion, by sintering and/or melting metal powders. In principle, EBAM utilizes a high-energy electron beam to melt and fuse metal powders to build solid parts with various materials, such as Ti-6Al-4V which is very difficult to fabricate using conventional processes. EBAM is one of a few Additive Manufacturing (AM) technologies capable of making full-density metallic parts and has drastically extended AM applications. The heat transfer analysis has been conducted in a simple case of a single-scan path with the effect of powder porosity investigated. In the actual EBAM process, the scan pattern is typically alternate raster. In this study, a coupled thermo-mechanical finite element model was developed to simulate the transient heat transfer, part residual stresses of alternate raster during the EBAM process subject to a moving heat source with a Gaussian volumetric distribution. The developed model was first examined against literature data. The coupled mechanical simulation is able to capture the evolution of the part residual stresses in EBAM.

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Corrigendum to A new hybrid approach for transient heat transfer analysis of convective radiative fin of functionally graded material under Lorentz force in Thermal Science and Engineering Progress 16 (2020) 100467

Thermal Science and Engineering Progress ◽

10.1016/j.tsep.2021.101121 ◽

2021 ◽

pp. 101121

Author(s):

George Oguntala ◽

Gbeminiyi Sobamowo ◽

Raed Abd-Alhameed

Keyword(s):

Heat Transfer ◽

Lorentz Force ◽

Functionally Graded Material ◽

Hybrid Approach ◽

Functionally Graded ◽

Heat Transfer Analysis ◽

Transient Heat Transfer ◽

Science And Engineering ◽

Graded Material

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A Hybrid Approach to Predict Residual Stresses Induced by Ball-End Tool Finishing Milling of a Bainitic Steel

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.223.391 ◽

2011 ◽

Vol 223 ◽

pp. 391-400 ◽

Cited By ~ 3

Author(s):

Nicolas Guillemot ◽

Benoît Beaubier ◽

Tarek Braham ◽

Claire Lartigue ◽

René Billardon

Keyword(s):

Residual Stresses ◽

Material Removal ◽

End Milling ◽

Hybrid Approach ◽

Cutting Tools ◽

Bainitic Steel ◽

Ir Camera ◽

Mechanical Loads ◽

Applied Loading ◽

Numerical Predictions

The objective of this study is to predict the residual stresses induced by ball-end milling using an hybrid approach based on a numerical simulation where thermo-mechanical loads equivalent to the cutting process are applied directly on to the final surface of the workpiece without modelling the material removal. The applied loading is derived from the measurement of the maximum cutting forces and the measurement by IR camera of the temperature in the tertiary shear zone. The 2D simplified model proposed herein is derived from the analysis of oblique cutting with elementary cutting tools and makes it possible to take account of the normal rake and local helix angles as well as the lead angle of the tool. The feasibility of the approach is assessed by comparing experimental measurements and numerical predictions of the residual stresses induced by ball-end tool finishing milling of flat specimens made of a bainitic steel.

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Research on Homogenization and Surface Integrity of Ti-6Al-4V Alloy by Longitudinal-Torsional Coupled Ultrasonic Vibration Ball-End Milling

10.20944/preprints201809.0032.v1 ◽

2018 ◽

Cited By ~ 1

Author(s):

Wanfei Ren ◽

Jinkai Xu ◽

Jieqiong Lin ◽

Zhanjiang Yu ◽

Peng Yu ◽

...

Keyword(s):

Surface Roughness ◽

Residual Stresses ◽

Cutting Force ◽

Ultrasonic Vibration ◽

High Frequency ◽

End Milling ◽

Cutting Speed ◽

Ball End Milling ◽

Average Value ◽

Cutting Experiments

This paper aims to study the surface homogenization and integrity of Ti-6Al-4V alloy by longitudinal-torsional coupled ultrasonic vibration assisted ball-end milling. A method of continuous processing between the flat surface and freeform surface connection is proposed by using ultrasonic vibration assisted ball-end precision milling, during this process, it is not necessary to exchange the cutting tool. The way has been explored for changing the homogenization of surface on Ti-6Al-4V by ultrasonic vibration-assisted milling (UVAM). Cutting experiments employing three parameters, cutting speed, feed rate and depth of cut and two types of machining forms using ball-end milling with UVAM and conventional milling (CM) respectively. The high frequency cutting force, finished surface roughness, topography and residual stresses on the surface and tool wear have been measured by advanced instruments. Particularly, adopting the high frequency cutting force measurement system, it is concluded cutting force in ball-end milling decreased significantly using UVAM as against CM. Moreover, the surface roughness by UVAM with ball-end milling is much better than the CM at a high cutting speed. However, an opposite trend is observed at a low cutting speed. Especially, there is a steep decrease from Ra 0.828 μm average value at 4000 rpm to Ra 0.129 μm average value at 5000 rpm. At the same time, the homogenization of surface roughness and residual stresses decrease significantly in UVAM as compared to which in CM when taking the transversal-longitudinal ratio into consideration. Cutting experiments and measuring results are demonstrated the validity and feasibility of UVAM with ball-end milling, and this method enjoys significant advantages compared to CM process.

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