• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2004.10a
• /
• pp.543-547
• /
• 2004

The molding characteristics of large-sized orthogonal stiffened plastic plates were investigated in the present study. Models with the geometry of 1800$\times$600$\times$12mm and 1200$\times$600$\times$12mm were designed for injection molding(IM) and injection-compression molding(ICM), respectively. To determine a mold system and reduce the warpage of the presented model after molding process, IM and ICM analyses using MOLDFLOW$^{TM}$ were performed. Also, the experiments were performed to verify the suggested mold system. It was shown that the change of molding method could significant effect on the warpage of designed model.l.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2007.10a
• /
• pp.271-274
• /
• 2007

Housing and insulation of electrical connectors are made of plastic resin by injection molding process. The metallic inner tube is easily deformed by high pressure during the injection process. In order to prevent deformation of the inner tube, it is desirable to simulate it by structural CAE analysis. However, it takes a long time to calculate the stress- of the part by commercially available injection molding CAE software with sufficient accuracy. In this study, structural analysis in conjunction with injection molding analysis is proposed to improve accuracy of the structural analysis. Pressure distribution on the inner tube is predicted by the injection molding CAE analysis, and then mapped onto the mesh of structural analysis by a mapping algorithm developed in this study. As a result reliable result is obtained in shorter time than the conventional method. The predicted deformation of the inner tube is compared with the actual part after experiment.

• Design & Manufacturing
• /
• v.17 no.2
• /
• pp.62-69
• /
• 2023

In this study, we conducted a study on the optimization of injection molding conditions to minimize deformation of plastic product. The charging management system housing of the vehicle was selected as the research subject. Melting temperature, cooling temperature, packing time, and packing pressure were selected as the main factors expected to affect the deformation of molded products. Each main factor was divided into 5 levels. Optimization of injection molding conditions to minimize deformation was performed using the Taguchi Method. We performed an analysis of variance (ANOVA) to identify significant factors affecting the deformation of plastic product. In order to select injection molding conditions that minimize deformation of plastic products, injection molding analysis was additionally performed for insignificant factors. We then compared the deformation of the molded part before and after optimization. As a result of comparing the injection analysis results of the basic conditions and the injection analysis results of the optimal conditions, it was confirmed that the amount of deformation after optimization was improved by about 10.9%.

• Fibers and Polymers
• /
• v.7 no.4
• /
• pp.404-413
• /
• 2006

This study examines multiple quality optimization of the injection molding for Polyether Ether Ketone (PEEK). It also looks into the dimensional deviation and strength of screws that are reduced and improved for the molding quality, respectively. This study applies the Taguchi method to cut down on the number of experiments and combines grey relational analysis to determine the optimal processing parameters for multiple quality characteristics. The quality characteristics of this experiment are the screws' outer diameter, tensile strength and twisting strength. First, one should determine the processing parameters that may affect the injection molding with the $L_{18}(2^1{\times}3^7)$ orthogonal, including mold temperature, pre-plasticity amount, injection pressure, injection speed, screw speed, packing pressure, packing time and cooling time. Then, the grey relational analysis, whose response table and response graph indicate the optimum processing parameters for multiple quality characteristics, is applied to resolve this drawback. The Taguchi method only takes a single quality characteristic into consideration. Finally, a processing parameter prediction system is established by using the back-propagation neural network. The percentage errors all fall within 2%, between the predicted values and the target values. This reveals that the prediction system established in this study produces excellent results.

• Proceedings of the KSME Conference
• /
• 2008.11a
• /
• pp.996-999
• /
• 2008

Aspheric polymer lens fabrication using isothermal compression molding is presented in this paper. Due to increasing definition of an image sensor, higher precision is required by a lens which can be used as a part of an imageforming optical module. Injection molding is a factory standard method for a polymer optical lens. But achievable precision using injection molding has a formidable limitation due to the machining of complex mold structure and melting and cooling down a polymer melt under high pressure condition during forming process. To overcome the precision requirement and limitation using injection molding method, isothermal compression molding is applied to fabrication of a polymer optical lens. The fabrication condition is determined by numerical simulations of temperature distribution and given material properties. Under the found condition, the lens having a high precision can successfully be reproduced and does not show birefringence which results often in optical degradation.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.12
• /
• pp.5709-5715
• /
• 2012

Injection molding product is commonly used for reducing the weight of automotive vehicle, and door regulator guide rail with plastic material is also made by injection molding process. In order to improve the injection molding performance of plastic regulator guide rail, optimal molding condition is suggested by numerical simulation and DOE after obtaining the sensitivity of parameters for regulator rail manufacturing on warpage and fill time. Furthermore, multi direct gate method and optimal cooling circuit are introduced to get the uniform temperature distribution and better cooling efficiency in molding product. The effect of the proposed design on the injection molding performance is verified by the test of prototype of plastic regulator guide rail.

• Transactions of Materials Processing
• /
• v.14 no.4 s.76
• /
• pp.368-374
• /
• 2005

In the present study we used a diagrammatic analysis of 6 sigma quality control and Taguchi method for injection molding of monitor back-cover, evaluated the influence on the cycle time with part design, mold design, molding process and standardization activity involving design and molding, adopted analysis of sensitivity and effective factors of the part design and molding process conditions for productivity, identified main design molding factors. The contributing factors for the final cycle time could be enumerated as follows; the thickness of hot spot, main nominal part thickness, coolant inlet temperature, melt temperature and cooling line layout, etc.. As a first step, all the critical factors of design process applied to the current monitor housing were investigated through 6 sigma process. Thereafter, the optimal and better critical factors found in the first step were applied to new product design to prove that our process was correct. The Moldflow was used for injection molding simulation, and Minitab software for the statistical analysis, respectively. Finally, the productivity of new design was increased about 33 percents for our specific case.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2004.05a
• /
• pp.269-272
• /
• 2004

The present study used a diagrammatic analysis of 6 sigma quality control and Taguchi method for injection molding process of monitor back-cover, evaluated the influence on the cycle time with part design, mold design, molding process and standardization activity involving design & molding, adopted analysis of sensitivity and effective factors of the part design and molding process conditions for productivity, identified main design molding factors, as critical ones influencing on the quality and productivity, of which is summarized as design guidance. The main contribution factors for cycle time can be sequentially enumerated as follows; hot spot, part thickness, coolant inlet temperature, melt temperature cooling line layout, etc.. As a first step critical factors of the design process of current monitor housing were investigated. And the optimal and better critical factors found in the first step were applied to a new product proving our process was correct. Moldflow software was used for injection molding simulation, and Minitab software for the statistical analysis. Finally, the productivity was increased by about 33 percents for our specific case.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2003.04a
• /
• pp.27-32
• /
• 2003

The wavelike flow mark phenomenon is one of the surface defects that can arise during the injection stage of the injection molding process. We have performed a numerical analysis using a finite element method for the injection molding to verify the validity of 'Go-over' hypothesis. Also, we have compared the results of numerical analysis with available experimental data. Numerical analysis results of the flow marks are qualitatively in good agreement with experimental data of reference, but are quantitatively deviated from experimental data in a consistent manner. A parametric study has been performed to examine the correlative effects of various injection molding processing parameters and material properties on the flow mark size.

• Transactions of Materials Processing
• /
• v.18 no.2
• /
• pp.128-134
• /
• 2009

The present study covers an integrated simulation method to evaluate optical performance of an aspheric plastic lens by connecting an injection molding analysis with a ray tracing simulation. Traditional ray tracing methods have based on the assumption that the optical properties of a lens are homogeneous throughout the entire volume. This assumption is to a certain extent unrealistic for injection-molded plastic lenses because material properties vary at every point due to the injection molding effects. To take into account the effects of the inhomogeneous optical properties of the molded lens, a numerical scheme is developed to calculate the distribution of refractive index induced from the injection molding process. This index distribution is then reflected onto CODE $V^{(R)}$ simulation and used to calculate ray paths in inhomogeneous media. The proposed tracing scheme is implemented on the tracing of an aspheric lens for a mobile phone camera module.