• Journal of the Korean Society for Precision Engineering
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• v.21 no.2
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• pp.27-34
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• 2004

In the injection molding of plastic optical lenses, the molding conditions have critical effects on the quality of the molded lenses. Since there are many molding parameters involved in injection molding process, determination of the molding conditions for lens molding is very important in order to precisely control the surface contours of an optical lens. Therefore this paper presents the application of neural network in suggesting the optimized molding conditions for improving the quality of molded parts based on data of FE Analysis carried out through CAE software, Timon-3D. Suggested model in this paper, which serves to learn from the data of FE Analysis and induce the values for optimized molding conditions. has been implemented for searching the molding conditions without void and with minimized thickness shrinkage at lens center of injection molding optical lens. As the result of this study. we have confirmed that void creation at the inside of lens is primarily determined by mold temperature and thickness shrinkage at center of lens is primarily determined by the parameters such as holding pressure and mold temperature.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.5
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• pp.105-112
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• 2017

In this study, plastics were deformed after molding due to the characteristics of the material. The Taguchi experimental design method was utilized to find the molding conditions that minimized deformation of the plastic bezel to be assembled in an automotive steering wheel. The injection molding conditions applied to the experimental design method are the melt temperature, cavity plate coolant temperature, core plate coolant temperature, and cooling time. Each condition was divided into five levels, and a total of 25 experiments were planned. However, instead of performing 25 actual molding experiments, the injection molding analysis was performed using the Moldflow program, and the deformation values for each molding analysis were obtained. The optimal molding conditions were obtained from these deformation values. The actual injection molding experiment using optimal molding conditions was compared with the deformation amount of the current molded product. The deformation was measured using a precise 3D scanner. The deformation amount of the molded product under optimal molding conditions was 16.1% lower than the deformation amount of the current molded product.

• Design & Manufacturing
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• v.14 no.1
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• pp.30-35
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• 2020

Plastic pulleys used for the purpose of power transmission have to very high roundness characteristics. The roundness of plastic pulleys is influenced by many factors. In this study, the effect of molding conditions on the roundness of pulleys was analyzed using a numerical analysis program. To improve the roundness, molding conditions that minimize the amount of deformation of the pulley were studied through an experimental design method. Among the experimental design methods, the Taguchi method was used, and the main molding conditions affecting the deformation of the pulley were the resin temperature and the holding pressure. It was found that the amount of deformation is reduced by about 2.86% when molding with the optimum molding conditions compared to when the optimum molding conditions are not applied.

• Transactions of Materials Processing
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• v.4 no.1
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• pp.39-47
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• 1995

The compression molding of SMC (sheet molding compund) at room temperature was analyzed based on rigid-viscoplastic approach by three dimensional finite element program. The developed program was tested by solving the three dimensional compression of wedge type specimens of aluminum alloys at various processing conditions. The simulation results were compared well to the experimental results available in the literature. based on this comparison the program was proved to be valid and was further applied in solving compression molding of SMC, which is a thermosetting material reinforced with chopped fiber glass. To investigate the effects of friction conditions and mold closing speeds for compression molding of SMC charge at room temperature, compressions of the cylindrical and rectangular shaped SMC were analyzed for various friction conditions and mold closing speeds. The calculated load values were compared to the experimental results for the compression molding of cylindrical specimen.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.6
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• pp.465-469
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• 2001

In injection molding short shot is one of the frequent and fatal defects. Experts of Injection molding usually adjust process conditions such as injection time, mold temperature, and melt temperature because it is most economic way in time and cost. However, it is difficult task to find appropriate process conditions for troubleshooting of short shot as injection molding process is a highly nonlinear system and process conditions are coupled. In this paper, a modular fuzzy neural network (MFNN) has been applied to injection molding process to shorten troubleshooting time of short shot. Based on melt temperature and fill time, a reasonable initial mo이 temperature is recommenced by the NFNN, and then the mold temperature is inputted to injection molding process. Depending on injection molding result, specifically the insufficient quantity of an injection molded part. and appropriate mold temperature is recommend repeatedly through the NFNN.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1609-1612
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• 2005

The effects of injection molding conditions on the uniformity and brightness of light guide plate(LGP) with micro-patterns were investigated in the present study. An injection molding system for stampers with mirco-pattern was designed and manufactured to perform experiment. Variations of injection molding speed, mold and melt temperature for LGP were considered in this work. Also, injection molding characteristics of LGP were investigated by numerical analysis using plastic injection molding commercial code. It was shown that injection molding conditions such as injection speed, melt temperature and mold temperature can have an effect on the uniformity and brightness of light guide plate.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2005.05a
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• pp.109-114
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• 2005

The large injection molded parts technology such as instrument panel, front and rear bumper are presented for a precision molding. Some lead time and cost are required to product these part from design to mass product. Recently, CAE is widely used in product design, mold design and analysis of molding conditions to reduce time and cost. The optimal molding conditions can be obtained by DOE(Design of Experiment). The optimal design applications with CAE and DOE have been used in small molded parts. However, application to the large molded body is not reported. In this paper, optimization of injection molding process is studied for quality control in mass production of automobile bumper. Mold temperature difference is chosen through robust design of injection molding process, the molding process being optimized in term of shrinkage and deflection. The optimal conditions through DOE are validated by using injection molding analysis.

• Design & Manufacturing
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• v.13 no.2
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• pp.12-16
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• 2019

For optimal injection molding, various molding conditions should be combined well. Therefore, engineers should be thoroughly familiar with mold design, fabrication, and injection molding. The choice of resin among the various molding conditions is closely related to the productivity of the molded part and the deformation after molding, so the engineer must select the appropriate resin. Engineers work on the basis of data provided by resin manufacturers during molding. However, in actual molding work, it is necessary to apply values slightly different from those provided to obtain molded articles of desired performance. In this study, various deformations of molded products were compared with respect to crystalline resin and amorphous resin when molded according to the data provided by the resin maker and molded at the changed values at the work site.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.12
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• pp.1619-1625
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• 2011

The objective of this study determine the molding conditions of a double-shot injection mold for fabricating a computer mouse using different materials, by performing three-dimensional injection molding analysis. In order to select the optical injection molding conditions, the effects of the injection time, the maximum injection pressure, the effect of packing time on the injection molding characteristics, and the product qualities were quantitatively examined. From the results of the injection molding analysis, the optimal injection molding conditions of the double-shot injection mold, which leads the molded product to the minimized shrinkage and deflection, were estimated. The results of the injection molding experiments, showed that an appropriate computer mouse can be fabricated using different materials when the identified optimal injection molding conditions are adopted.

• Elastomers and Composites
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• v.52 no.4
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• pp.317-325
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• 2017

Molding conditions can be described as factors that determine the quality of a product obtained from injection molding. Many studies have been performed on the injection molding pressure, injection temperature, packing pressure and other molding conditions related to part quality. However, the most accessible factor among the adjustable molding conditions during actual injection is the injection speed. In this study, we simulated the variation of the physical quantity according to injection speed and performed experiments to understand the effect of injection speed on the actual product. A CAE analysis program (Moldflow) was used to simulate and analyze the results using PC and PBT for two models. In order to compare these results with the experimental results, an actual injection molding was performed for each injection speed, and the correlation between simulation and injection molding, especially for the shrinkage of the molded article, was discussed.