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

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.

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1032 ◽  
Author(s):  
Jae-Hyeon Ha ◽  
Choon-Man Lee

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.


2017 ◽  
Vol 09 (02) ◽  
pp. 1750028
Author(s):  
Hany H. Sherief ◽  
Allam A. Allam

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.


1984 ◽  
Vol 106 (3) ◽  
pp. 179-186 ◽  
Author(s):  
P. R. Dawson ◽  
S. Malkin

The analysis of an inclined plane heat source moving along the surface of a semi-infinite solid is presented. Material passing by the heat source is eliminated from the analysis to simulate its removal by an orthogonal cutting process. The solution, expressed in terms of dimensionless parameters, is obtained by solving the heat equation numerically with the finite element method for a wide range of cutting conditions. The solution is used to evaluate shear plane temperatures in orthogonal machining and grinding zone temperatures in conventional and creep feed grinding.


1975 ◽  
Vol 97 (1) ◽  
pp. 39-44
Author(s):  
C. S. Kang ◽  
Y. P. Chang

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.


2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Banjara Kotresha ◽  
N. Gnanasekaran

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.


Author(s):  
Mohsen Akbari ◽  
David Sinton ◽  
Majid Bahrami

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.


Author(s):  
Y Huang ◽  
S Y Liang

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.


2020 ◽  
Vol 42 (3) ◽  
pp. 271-282
Author(s):  
OLEG IVANOV

The general characteristics of planetary systems are described. Well-known heat sources of evolution are considered. A new type of heat source, variations of kinematic parameters in a dynamical system, is proposed. The inconsistency of the perovskite-post-perovskite heat model is proved. Calculations of inertia moments relative to the D boundary on the Earth are given. The 9 times difference allows us to claim that the sliding of the upper layers at the Earth's rotation speed variations emit heat by viscous friction.This heat is the basis of mantle convection and lithospheric plate tectonics.


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