scholarly journals Effect of gas on the polymer temperature in external gas-assisted injection molding

2019 ◽  
Vol 39 (6) ◽  
pp. 587-595
Author(s):  
Taidong Li ◽  
Jiquan Li ◽  
Frederik Desplentere ◽  
Xinxin Xia ◽  
Xiang Peng ◽  
...  
Keyword(s):  
Injection Molding ◽  
Delay Time ◽  
Quantitative Methods ◽  
Transient Heat Conduction ◽  
Simulation Methods ◽  
Conduction Model ◽  
One Dimensional ◽  
Simulation Results ◽  
Heat Preservation ◽  
Conventional Injection Molding

AbstractThe introduction of gas is the principal difference between external gas-assisted injection molding (EGAIM) and conventional injection molding. In this study, the effects of gas thickness and gas delay time on polymer temperature were discussed. A modified one-dimensional transient heat conduction model of polymer was established to reveal the relationships between polymer temperature and gas thickness and gas delay time in EGAIM. The temperature histories of polymer were obtained by the simulation methods, including Moldflow and ANSYS, and were verified by comparing the experimental data to numerical simulation results. The effects of gas thickness and gas delay time on the temperature histories of polymer will be discussed in detail. The results showed that the polymer temperature is strongly affected by the heat preservation of gas, which in turn, increases with the increase of gas thickness and delay time. This paper provides quantitative methods and theoretical guidance for the study of the effects of gas on the polymer temperature in EGAIM.

scholarly journals Reducing the Burn Marks on Injection-Molded Parts by External Gas-Assisted Injection Molding

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4087
Author(s):  
Jiquan Li ◽  
Wenyong Liu ◽  
Xinxin Xia ◽  
Hangchao Zhou ◽  
Liting Jing ◽  
...  
Keyword(s):  
Image Processing ◽  
Injection Molding ◽  
Delay Time ◽  
Quantitative Method ◽  
Surface Defect ◽  
Processing Method ◽  
Traditional Methods ◽  
Molded Parts ◽  
Injection Molded ◽  
Conventional Injection Molding

A burn mark is a sort of serious surface defect on injection-molded parts. In some cases, it can be difficult to reduce the burn marks by traditional methods. In this study, external gas-assisted injection molding (EGAIM) was introduced to reduce the burn marks, as EGAIM has been reported to reduce the holding pressure. The parts with different severities of burn marks were produced by EGAIM and conventional injection molding (CIM) with the same molding parameters but different gas parameters. The burn marks were quantified by an image processing method and the quantitative method was introduced to discuss the influence of the gas parameters on burn marks. The results show that the burn marks can be eliminated by EGAIM without changing the structure of the part or the mold, and the severity of the burn marks changed from 4.98% with CIM to 0% with EGAIM. Additionally, the gas delay time is the most important gas parameter affecting the burn marks.

Particle temperature distribution in a dust flame

2010 ◽  
Vol 224 (2) ◽  
pp. 363-367
Author(s):  
A S Shahrbabaki ◽  
M Dodangeh
Keyword(s):  
Particle Size ◽  
Heat Conduction ◽  
Temperature Profile ◽  
Particle Temperature ◽  
Transient Heat Conduction ◽  
Order Model ◽  
Conduction Model ◽  
One Dimensional ◽  
Dust Flame ◽  
Good Agreement

An unsteady one-dimensional heat conduction model is used to determine the particle temperature profile in suspension fuels by using a perturbation method. A second-order model is presented for transient heat conduction in a spherical particle. The radiation term is considered in the boundary conditions, which plays an important role in the dust flame. The effects of particle size and Biot number on the temperature profile are investigated. The results are in good agreement with the numerical solution.

Determination of Optimum Process Parameters in Gas-Assisted Injection Molding

2011 ◽  
Vol 143-144 ◽  
pp. 494-498
Author(s):  
Ke Ming Zi ◽  
Li Heng Chen
Keyword(s):  
Injection Molding ◽  
Delay Time ◽  
Optimization Design ◽  
Gas Pressure ◽  
Optimum Process ◽  
Injection Molding Process ◽  
Technological Parameters ◽  
Molding Process ◽  
Element Analysis ◽  
Melt Temperature

With finite element analysis software Moldflow, numerical simulation and studies about FM truck roof handle were conducted on gas-assisted injection molding process. The influences of melt pre-injection shot, gas pressure, delay time and melt temperature were observed by using multi-factor orthogonal experimental method. According to the analysis of the factors' impact on evaluation index, the optimized parameter combination is obtained. Therefore the optimization design of technological parameters is done. The results show that during the gas-assisted injection molding, optimum pre-injection shot is 94%,gas pressure is 15MPa,delay time is 0.5s,melt temperature is 240 oC. This study provided a more practical approach for the gas-assisted injection molding process optimization.

Key Technologies Research on Color Contour Map of 3D Injection Molding Simulation Results

2012 ◽  
Vol 217-219 ◽  
pp. 1998-2001
Author(s):  
Tie Geng ◽  
Qing Hai Ren ◽  
Wei Qing Tu ◽  
Dan Dan Liu
Keyword(s):  
Injection Molding ◽  
Color Image ◽  
Three Dimensional ◽  
Physical Field ◽  
Contour Map ◽  
Image Rendering ◽  
Color Range ◽  
Key Technologies ◽  
Injection Molding Simulation ◽  
Simulation Results

According to the color contour map of the 3D injection molding simulation results, the commonly used color contour map drawing algorithm was researched, and a three-dimensional color image rendering algorithm which based on the "physical field values and color range mapping" was given too. And the key technologies of the algorithm which was used to draw 3D color contour map were introduced in detail. In the end, an example was given.

Enhanced Explicit Scheme to Solve Transient Heat Conduction Problem

2007 ◽  
Vol 2 (1) ◽  
Author(s):  
Ganesh Hegde ◽  
Madhu Gattumane
Keyword(s):  
Heat Conduction ◽  
Correction Factor ◽  
Truncation Error ◽  
Transient Heat Conduction ◽  
Explicit Scheme ◽  
Stability And Convergence ◽  
Two Dimensional ◽  
Time Step ◽  
One Dimensional ◽  
Partial Derivatives

Improvement in accuracy without sacrificing stability and convergence of the solution to unsteady diffusion heat transfer problems by computational method of enhanced explicit scheme (EES), has been achieved and demonstrated, through transient one dimensional and two dimensional heat conduction. The truncation error induced in the explicit scheme using finite difference technique is eliminated by optimization of partial derivatives in the Taylor series expansion, by application of interface theory developed by the authors. This theory, in its simple terms gives the optimum values to the decision vectors in a redundant linear equation. The time derivatives and the spatial partial derivatives in the transient heat conduction, take the values depending on the time step chosen and grid size assumed. The time correction factor and the space correction factor defined by step sizes govern the accuracy, stability and convergence of EES. The comparison of the results of EES with analytical results, show decreased error as compared to the result of explicit scheme. The paper has an objective of reducing error in the explicit scheme by elimination of truncation error introduced by neglecting the higher order terms in the expansion of the governing function. As the pilot examples of the exercise, the implementation is aimed at solving one-dimensional and two-dimensional problems of transient heat conduction and compared with the results cited in the referred literature.

scholarly journals A one-dimensional modified TASEP model on a track of variable length: analytical and computational results

2021 ◽  
Vol 2090 (1) ◽  
pp. 012025
Author(s):  
B. Reed ◽  
E. Aldrich ◽  
L. Stoleriu ◽  
D.A. Mazilu ◽  
I. Mazilu
Keyword(s):  
Monte Carlo ◽  
Molecular Motors ◽  
Mean Field Theory ◽  
Mean Field ◽  
Limited Range ◽  
Field Methods ◽  
One Dimensional ◽  
Emergent Features ◽  
Simulation Results ◽  
Mean Field Methods

Abstract We present analytical solutions and Monte Carlo simulation results for a one-dimensional modified TASEP model inspired by the interplay between molecular motors and their cellular tracks of variable lengths, known as microtubules. Our TASEP model incorporates rules for changes in the length of the track based on the occupation of the first two sites. Using mean-field theory, we derive analytical results for the particle densities and particle currents and compare them with Monte Carlo simulations. These results show the limited range of mean-field methods for models with localized high correlation between particles. The variability in length adds to the complexity of the model, leading to emergent features for the evolution of particle densities and particle currents compared to the traditional TASEP model.

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