Modelling the pressure die casting process with the boundary element method: Steady state approximation

1990 ◽  
Vol 30 (7) ◽  
pp. 1275-1299 ◽  
Author(s):  
K. Davey ◽  
S. Hinduja
Keyword(s):  
Steady State ◽  
Boundary Element Method ◽  
Boundary Element ◽  
Die Casting ◽  
Casting Process ◽  
State Approximation ◽  
Steady State Approximation ◽  
Die Casting Process ◽  
Pressure Die Casting ◽  
Element Method

Modelling the pressure die casting process with the boundary element method: Die deformation model for flash prevention

1998 ◽  
Vol 212 (3) ◽  
pp. 197-215 ◽  
Author(s):  
J Milroy ◽  
S Hinduja ◽  
K Davey
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Die Casting ◽  
Injection Pressure ◽  
Casting Process ◽  
Operating Conditions ◽  
Deformation Model ◽  
The Individual ◽  
Pressure Die Casting ◽  
Element Method

In pressure die casting, the thermal loads, injection pressure and clamping forces cause the individual blocks of a die to deform. This deformation results in gaps between the interface surfaces which, if big enough and in the vicinity of the cavity, permit material to seep into the gaps, causing flash. This paper describes a thermoelastic model to predict the deformation of the die so that it can be machined to prevent flash. The model is based on the boundary element method and allows the use of linear isoparametric or quadratic subparametric elements. Each die block is analysed as a separate problem. To avoid the occurrence of flash, the model suggests the amounts that should be machined from each die block. The predicted deformation has been experimentally verified by measuring the profile of a test die using displacement transducers and die impressions. It is shown that there is good agreement between the predicted and experimental results for different operating conditions. By machining the amounts suggested by the model, the test die was run without flash at operating conditions that had previously resulted in flash.

An Experimental and Numerical Investigation into the Thermal Behavior of the Pressure Die Casting Process

1999 ◽  
Vol 122 (1) ◽  
pp. 90-99 ◽  
Author(s):  
S. Bounds ◽  
K. Davey ◽  
S. Hinduja
Keyword(s):  
Heat Transfer ◽  
Die Casting ◽  
Casting Process ◽  
Heat Extraction ◽  
Transfer Coefficients ◽  
Average Heat ◽  
Heat Transfer Coefficients ◽  
Die Casting Process ◽  
Pressure Die Casting ◽  
Element Method

The modeling of the pressure die casting process generally requires the specification of heat transfer coefficients at the surfaces of the die. The coefficients at the cavity-casting interface and at the cooling channel surfaces are of particular importance. In order to provide estimates for these heat transfer coefficients, the behavior of a specifically designed zinc alloy casting is investigated using a three dimensional thermal model whose predictions are supported by experimentally obtained results. The numerical model uses the boundary element method for the dies, as surface temperatures are of particular importance, and the finite element method for the casting, where the nonlinear material behavior makes this technique suitable. The experimental data comprises of thermocouple measurements of both die, casting, and coolant temperatures for three sets of operating conditions. These measurements are complemented by qualitative data of casting defects caused by incomplete solidification and thermal imaging temperature measurements. An experimental technique for obtaining average heat transfer coefficients for the casting–die interface is presented. Although the technique circumvents the need to place thermocouples in the casting and provides average heat transfer coefficients of sufficient accuracy for modeling purposes, it is not sufficiently responsive to provide accurate transient information. The presence of coolant boiling is detected by its effect on the rates of heat extraction. Heat transfer coefficients are determined for the cooling channels using a boiling model. Comparison between predicted and experimental rates of heat transfer to the coolant support the need for a boiling model. Good agreement is obtained between experimental and numerical predictions. [S1087-1357(00)00601-8]

Predicting heat extraction due to boiling in the cooling channels during the pressure die casting process

2000 ◽  
Vol 214 (3) ◽  
pp. 465-482 ◽  
Author(s):  
L D Clark ◽  
I Rosindale ◽  
K Davey ◽  
S Hinduja ◽  
P J Dooling
Keyword(s):  
Heat Transfer ◽  
Forced Convection ◽  
Die Casting ◽  
Casting Process ◽  
Nucleate Boiling ◽  
Heat Extraction ◽  
Film Boiling ◽  
Cooling Channels ◽  
Die Casting Process ◽  
Pressure Die Casting

The effect of boiling on the rate of heat extraction by cooling channels employed in pressure die casting dies is investigated. The cooling effect of the channels is simulated using a model that accounts for subcooled nucleate boiling and transitional film boiling as well as forced convection. The boiling model provides a continuous relationship between the rate of heat transfer and temperature, and can be applied to surfaces where forced convection, subcooled nucleate boiling and transitional film boiling are taking place in close proximity. The effects of physical parameters such as flow velocity, degree of subcooling, system pressure and bulk temperature are taken into account. Experimental results are obtained using a rig that simulates the pressure die casting process. The results are compared with the model predictions and are found to show good agreement. Instrumented field tests, on an industrial die casting machine, are also reported. These tests show the beneficial effects of boiling heat transfer in the pressure die casting process, including a 75 per cent increase in the production rate for the test component.

Numerical modelling of convection-diffusion problems with first-order chemical reaction using the dual reciprocity boundary element method

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Salam Adel Al-Bayati ◽  
Luiz C. Wrobel
Keyword(s):  
Steady State ◽  
Boundary Element Method ◽  
Boundary Element ◽  
Content Type ◽  
Convection Diffusion ◽  
First Order ◽  
Order Chemical Reaction ◽  
First Order Chemical Reaction ◽  
Diffusion Problems ◽  
Element Method

Purpose The purpose of this paper is to describe an extension of the boundary element method (BEM) and the dual reciprocity boundary element method (DRBEM) formulations developed for one- and two-dimensional steady-state problems, to analyse transient convection–diffusion problems associated with first-order chemical reaction. Design/methodology/approach The mathematical modelling has used a dual reciprocity approximation to transform the domain integrals arising in the transient equation into equivalent boundary integrals. The integral representation formula for the corresponding problem is obtained from the Green’s second identity, using the fundamental solution of the corresponding steady-state equation with constant coefficients. The finite difference method is used to simulate the time evolution procedure for solving the resulting system of equations. Three different radial basis functions have been successfully implemented to increase the accuracy of the solution and improving the rate of convergence. Findings The numerical results obtained demonstrate the excellent agreement with the analytical solutions to establish the validity of the proposed approach and to confirm its efficiency. Originality/value Finally, the proposed BEM and DRBEM numerical solutions have not displayed any artificial diffusion, oscillatory behaviour or damping of the wave front, as appears in other different numerical methods.

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