scholarly journals A Study on the Thermal Effect by Multi Heat Sources and Machining Characteristics of Laser and Induction Assisted Milling

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1032 ◽  
Author(s):  
Jae-Hyeon Ha ◽  
Choon-Man Lee
Keyword(s):  
Temperature Distribution ◽  
Heat Source ◽  
Thermal Effect ◽  
Measured Temperature ◽  
Heat Sources ◽  
High Productivity ◽  
Measurement Experiment ◽  
Laser Induction ◽  
Machining Characteristics

Thermally assisted machining (TAM) is an effective method for difficult-to-cut materials, and works by locally preheating the workpiece using various heat sources, such as laser, induction, and plasma. Recently, many researchers have studied TAM because of its low manufacturing costs, high productivity, and quality of materials. Laser assisted machining (LAM) has been studied by many researchers, but studies on TAM using induction or plasma heat sources, which are much cheaper than lasers, have been carried out by only a few researchers. Lasers have an excellent preheating effect, but are expensive, and the temperature of the heated workpiece drops quickly. Here, multi heat sources were used to solve the shortage in supplied heat source with a single heat source. Induction was applied as an additional heat source. The purpose of this study is to analyze the thermal effect and temperature distribution of single heat source and multi heat sources, and compare the machining characteristics according to heat source types. In order to analyze the preheating effect according to the feed rate of the heat sources, a temperature measurement experiment using thermocouples was carried out, and the efficiency of the thermal effect using multi heat sources was verified. In addition, the effectiveness of the thermal analysis results was verified by comparison with the measured temperature distribution. The machining characteristics of Inconel 718 and Ti-6Al-4V with laser, induction, and laser-induction assisted milling (LIAMill) were analyzed, by cutting force and surface roughness.

scholarly journals Alternative solid fuels combustion in small heat source

2018 ◽  
Vol 168 ◽  
pp. 08002 ◽  
Author(s):  
Michal Holubčík ◽  
Nikola Kantová ◽  
Jozef Jandačka ◽  
Zuzana Kolková
Keyword(s):  
Heat Source ◽  
Alternative Fuels ◽  
Beech Wood ◽  
Major Influence ◽  
Heat Output ◽  
Heat Sources ◽  
Gaseous Emissions ◽  
Output Efficiency ◽  
Negative Factors

Air quality is related to the using of solid fuel based heat sources in which the human factor has a major influence on the quality of combustion, which can lead to higher emissions into the air. One of the negative factors is the use of alternative fuels in heat sources. The article deals with the combustion of various alternative fuels, on a waste basis, in small heat sources. There were tested 4 types of fuels: beech wood pieces, 2 types of solid alternative fuel on the base of municipal waste and wood waste. In the experiment, it was tested the influence of used fuel in the fireplace on the heat output, efficiency, production of gaseous emissions and particulate matter. The results confirmed that combustion of fuels not recommended by the heat source manufacturer reduces the efficiency of combustion and significantly increases all monitored emissions.

Analytical Thermal Models of Oblique Moving Heat Source for Deep Grinding and Cutting

2000 ◽  
Vol 123 (2) ◽  
pp. 185-190 ◽  
Author(s):  
T. Jin ◽  
G. Q. Cai
Keyword(s):  
Temperature Distribution ◽  
Heat Source ◽  
High Efficiency ◽  
Orthogonal Cutting ◽  
Heat Sources ◽  
Thermal Models ◽  
Creep Feed ◽  
Moving Direction ◽  
Transfer Problems ◽  
Zone Temperature

Three related analytical thermal models of plane heat source moving obliquely along the surface of a semi-infinite solid are presented. The temperature distribution of grinding zone under deep-cut conditions is investigated with these models. It is proposed that the oblique angle of the heat source plane to its moving direction has an essential influence on the grinding zone temperature rise and its distribution of high efficiency deep grinding (HEDG). Compared with that in creep-feed grinding, HEDG has a different form of heat flux distribution in grinding zone and should be treated with different thermal models. The temperature distribution at the shear zone of orthogonal cutting is also briefly discussed with the thermal models. The models developed in the paper provide a more rational and integrated analytical basis for dealing with the heat transfer problems of inclined moving heat sources.

Temperature Distribution in a Hollow Cylindrical Workpiece During Machining: Theoretical Model and Experimental Results

1991 ◽  
Vol 113 (4) ◽  
pp. 373-380 ◽  
Author(s):  
G. Subramani ◽  
M. C. Whitmore ◽  
S. G. Kapoor ◽  
R. E. DeVor
Keyword(s):  
Temperature Field ◽  
Temperature Distribution ◽  
Heat Source ◽  
Analytical Model ◽  
Initial Conditions ◽  
Temperature Response ◽  
Test Facility ◽  
Measured Temperature ◽  
Cylindrical Workpiece ◽  
Cylinder Bore

In this paper, an analytical model is developed for computation of the temperature distribution in a hollow cylindrical workpiece during machining with a single point tool. Such a model is useful for prediction of machined surface error arising from thermal expansion of the workpiece during machining. The model considers the interface between the tool and the workpiece to be a helically moving volumetric heat source. The governing equation satisfied by the temperature field, along with the appropriate boundary and initial conditions, is solved using the method of integral transforms. The experimental test facility used for the conduct of experiments for measurement of the temperature response in a cylindrical workpiece, namely a cylinder bore, during machining is discussed. The results from tests conducted using a laser as a heat source to verify the analytical model for temperature field are then presented. Several cylinder boring tests have been conducted, and the results from these tests along with the analysis performed with the temperature data to calibrate the temperature model are then discussed. Comparisons between predicted and measured temperature response in a cylinder bore during machining show good agreement.

A NEW HEAT SOURCE MODEL FOR KEYHOLE MODE LASER WELDING

2021 ◽  
pp. 1-14
Author(s):  
Samuel Lorin ◽  
Julia Madrid ◽  
Rikard Söderberg ◽  
Kristina Wärmefjord
Keyword(s):  
Heat Source ◽  
Laser Welding ◽  
Heat Input ◽  
Source Model ◽  
Fluid Simulation ◽  
Heat Sources ◽  
Heat Source Model ◽  
Mode Laser ◽  
Standard Heat

Abstract Laser welding is a common technique for joining metals in many manufacturing industries. Due to the heat input and the resulting melting and solidification, the parts deform causing residual distortion and residual stresses. To assure the geometrical and functional quality of the product, Computational Welding Mechanics (CWM) is often employed in the design phase to predict the outcome of different design proposals. Furthermore, CWM can be used to design the welding process with the objective of assuring the quality of the weld. However, welding is a complex multi-physical process and in a design process it is typically not feasible, for example, to employ fluid simulation of the weld pool in order to predict deformation, especially if a set of design proposals is under investigation. Instead, what is used is a heat source that emulates the heat input from the melt pool. However, standard heat sources are typically not flexible enough to capture the fusion zone for deep keyhole mode laser welding. In this paper, a new heat source model for keyhole mode laser welding is presented. In an industrial case study, a number of bead on plate welds have been employed to compare standard weld heat sources and develop the new heat source model. The proposed heat source is based on a combination of standard heat sources. From the study, it was concluded that the standard heat sources could not predict the observed melted zone for certain industrial application while the new heat source was able to do so.

2D Axisymmetric Problem for a Sphere with Heat Sources in the Theory of Generalized Thermoviscoelasticity

2017 ◽  
Vol 09 (02) ◽  
pp. 1750028
Author(s):  
Hany H. Sherief ◽  
Allam A. Allam
Keyword(s):  
Temperature Distribution ◽  
Heat Source ◽  
Axisymmetric Problem ◽  
Solid Sphere ◽  
Heat Sources ◽  
Inner Sphere ◽  
Axisymmetric Temperature

A solid sphere composed of a thermoviscoelastic material is subjected to an axisymmetric temperature distribution on its surface that is traction free. A distributed heat source acts inside an inner sphere. The problem is solved analytically and numerically. The solutions are represented graphically for different cases.

Effects of Change of Phase on Temperature Distribution Due to a Moving Heat Source

1975 ◽  
Vol 97 (1) ◽  
pp. 39-44
Author(s):  
C. S. Kang ◽  
Y. P. Chang
Keyword(s):  
Boundary Condition ◽  
Temperature Field ◽  
Temperature Distribution ◽  
Heat Source ◽  
Heat Input ◽  
Line Source ◽  
Initial Temperature ◽  
The Other ◽  
Heat Sources ◽  
Moving Heat Source

This paper presents a numerical method for the solution of problems of moving heat sources with change of phase and with any boundary condition. Calculated results of two specific cases are shown: one for a plane moving source in a rod and the other for a line source in a plate. It is found that for low heat input and/or low initial temperature, the change of phase does not affect significantly the temperature distribution in the medium, were it of solid only. However, the higher the heat input and/or the initial temperature, the larger is the effect of phase-change to the temperature field.

A Synergistic Combination of Thermal Models for Optimal Temperature Distribution of Discrete Sources Through Metal Foams in a Vertical Channel

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Banjara Kotresha ◽  
N. Gnanasekaran
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Heat Source ◽  
Metal Foam ◽  
Vertical Channel ◽  
Metal Foams ◽  
Local Thermal Equilibrium ◽  
High Porosity ◽  
Heat Sources ◽  
Excess Temperature

This paper discusses about the numerical prediction of forced convection heat transfer through high-porosity metal foams with discrete heat sources in a vertical channel. The physical geometry consists of a discrete heat source assembly placed at the center of the channel along with high thermal conductivity porous metal foams in order to enhance the heat transfer. The novelty of the present work is the use of combination of local thermal equilibrium (LTE) model and local thermal nonequilibrium (LTNE) model for the metal foam region to investigate the temperature distribution of the heat sources and to obtain an optimal heat distribution so as to achieve isothermal condition. Aluminum and copper metal foams of 10 PPI having a thickness of 20 mm are considered for the numerical simulations. The metal foam region is considered as homogeneous porous media and numerically modeled using Darcy Extended Forchheimer model. The proposed methodology is validated using the experimental results available in literature. The results of the present numerical solution indicate that the excess temperature of the bottom heat source reduces by 100 °C with the use of aluminum metal foam. The overall temperature of the vertical channel reduces based on the combination of LTE and LTNE models compared to only LTNE model. The results of excess temperature for both the empty and the metal foam filled vertical channels are presented in this work.

Moving Heat Sources in a Half Space: Effect of Source Geometry

2009 ◽  
Author(s):  
Mohsen Akbari ◽  
David Sinton ◽  
Majid Bahrami
Keyword(s):  
Temperature Distribution ◽  
Heat Source ◽  
Half Space ◽  
Source Area ◽  
Heat Sources ◽  
Shape Variation ◽  
Wide Range ◽  
Space Effect ◽  
Moving Plane ◽  
Transient And Steady State

The time dependent temperature distribution due to a moving plane heat source of hyperelliptical geometry is analytically studied in this work. The effect of the heat source shape is investigated starting from the general solution of a moving heat source on a half space. Selecting the square root of the heat source area as a length scale, it is observed that the temperature distribution becomes a weak function of the heat source shape. Variation of temperature field with respect to the source aspect ratio, velocity and depth is studied. The analysis presented in this work is valid for both transient and steady-state conditions. In addition, the hyperellipse formulation provided here covers a wide range of shapes including star, rhombic, ellipse, circle, square, rectangle and rectangle with rounded corners.

Modelling of the cutting temperature distribution under the tool flank wear effect

2003 ◽  
Vol 217 (11) ◽  
pp. 1195-1208 ◽  
Author(s):  
Y Huang ◽  
S Y Liang
Keyword(s):  
Temperature Distribution ◽  
Tool Wear ◽  
Heat Source ◽  
Shear Zone ◽  
Temperature Rise ◽  
Flank Wear ◽  
Cutting Temperature ◽  
Infinite Medium ◽  
Heat Sources ◽  
Moving Band

The understanding of cutting temperature distribution at the presence of tool wear can aid in addressing important metal cutting issues such as part surface integrity, tool life and dimensional tolerance under practical operating conditions. The effect of tool wear on the cutting temperature distribution was first modelled by Chao and Trigger and there have been very few followers since. In Chao's model, the primary heat source was assumed to have no effect on the workpiece temperature rise and the chip temperature rise was treated as a bulk quantity. This paper analytically quantifies the tool wear effect by taking into account the contributions of the primary heat source and considering the distribution of chip temperature rise. On the chip side, the primary shear zone is modelled as a uniform moving oblique band heat source and the secondary shear zone as a non-uniform moving band heat source within a semi-infinite medium. On the tool side, the effects of both the secondary and the rubbing heat sources are modelled as non-uniform static rectangular heat sources within a semi-infinite medium. For the workpiece side, the study models the primary shear zone as a uniform moving oblique band heat source and the rubbing heat source as a non-uniform moving band heat source within a semi-infinite medium. The proposed model is verified based on the published experimental data in the orthogonal cutting of Armco iron. Furthermore, a comparison case is presented on the temperature variation with respect to cutting speed, feed rate and flank wear length.

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