• Design & Manufacturing
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• v.2 no.5
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• pp.11-15
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• 2008

A micro-injection mold for ultra-thin-walled plate was considered in this work. The proposed mold system is for the fabrication of ultra-thin walled plastic plate with micro features by injection molding. As the injection molding of thin-walled plastic, which has the thickness under $400{\mu}m$, itself is not easy, the injection molding of the micro-features in the thin-walled structure is more complicated and difficult. To investigate the basic phenomenon of the ultra-thin walled part during the injection molding process, design of the part and mold system were performed in the present study. The injection molding and structural analysis of the suggested part and mold system were also performed. Consequently, injection molding system for ultra-thin walled plate with micro features were manufactured and presented.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.7 s.172
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• pp.177-184
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• 2005

Recently, the engineering designer of injection mould has become more and more dependent on the CAE. In the design factors of injection mould, the shrinkage rate should be considered as one of the important performances to produce the reliable products. therefore the shrinkage rate can be mostly calculated by the MoldFlow and Pro-engineering. in the design process. However it is not easy to predict the shrinkage rate of a plastic injection mold in its design process because the analysis can take minutes to hours, the high computational costs of performing the analysis limit their use in design optimization. In this study, the surrogate models, DACE model, based on the Kriging in order to optimize the shrinkage rate of electric microwave oven window is used in lieu of the original models, facilitating design optimization.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.183-185
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• 1998

In this paper, a magnetic circuit of plastic magnet roller for laser printer is presented. The magnetization direction of plastic magnet is decided by the flux distribution of injection mold during the manufacturing process. The injection mold is designed and analysed to fit the design specification. The experiment showed that the flux distribution of a magnet is good agreement of the given specification.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.5
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• pp.84-90
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• 2018

When producing a plastic horn cover for an automobile, since the interval between the ribs on the inner surface is narrow, conventional cooling channels cannot be applied and cooling of the mold is difficult. For this reason, the molding operation cannot be completed within a set cycle time. In this study, a conformal cooling channel was applied on the mold to solve the cooling problem. Injection molding simulation was carried out to confirm the effectiveness of the conformal cooling channel. In the analysis results, the mold temperature at the rib section decreased by 33%, and the mold temperature also decreased by 31%. This reduction in temperature allowed for molding within a set cycle time and demonstrated the effectiveness of the conformal cooling channel.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.5 s.236
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• pp.647-654
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• 2005

This research Proposes a Process design of injection molded microcellular plastic gears for enhancing the fatigue strength/durability and accuracy of the gears applying thermodynamic instability to microcellular foaming process. To develop the injection molded plastic gears by way of microceliular process, it is absolutely necessary the following two process design. The first is microcellular forming process for enhancing the strength/durability of plastic gears. To be microcellular process succeeded, based on the microcellular principle, mechanical apparatus is designed where nucleation and cell growth are to be generated renewably. The second is the counter pressure process which is mainly fur improving the tooth surface roughness and the accuracy of microcellular gears. For the former process, screw, nozzle and gas equipment are newly designed, and for the latter, counter pressure by nitrogen gas is intentionally brought about into mold cavity when injecting plastic gears. Based on the proposed process design, using gear mold, experiments of injection molding show that, in internal space of plastic gears, microcellular nuclear cells less than 5 lim in diameter have been generated homogeneously via electron microscope photos.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.6
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• pp.1227-1237
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• 1988

A practically useful CAD system for mold design in the plastic injection molding processes has been developed. Even though many efforts have been tried to simulated the injection molding process, this is the first attempt toward an automatic mold design system instead of a manufacturing or a simulation system. In this system the computational routines, the data base for mold design, and the routines for three dimensional modeling are blended together so that the designed mold is obtained as a solid model. For this development, the following problems have been solved. First, the modeling capability of the plastic parts has been implemented by incorporating the modeling routines of a constructive solid geometric modeling system and developing a constant thickness modeling conditions, and that of standard mold bases have been established. Third, the experimental know-how and the empirical formulae have been collected and blended together with the modeling routines of a geometric modeling system to provide the high level commands for designing mold.

• Journal of Korean Society for Quality Management
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• v.29 no.3
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• pp.86-96
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• 2001

The objective of this research is to develop a robust design methodology for plastic injection molded parts wherein warpage will be minimized by a complex method which is a kind of a simple direct search method. The design space considered for optimization is divided Into two sub-design space : mold and process conditions. Warpage is quantified using the Moldflow injection molding simulation software. The design methodology was applied to an actual part of a fax machine, the Guide-ASF model, through two different design policies. The significance of this study is the synthesis of a computer simulation of injection molding process and optimization technique to determine the optimal robust design solution.

• Design & Manufacturing
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• v.13 no.2
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• pp.30-36
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• 2019

Traditional cell culture(2-dimensional) is the method that provide a nutrient and environment on a flat surface to cultivate cells into a single layer. Since the cell characteristics of 2D culture method is different from the characteristics of the cells cultured in the body, attempts to cultivate the cells in an environment similar to the body environment are actively proceeding in the industry, academy, and research institutes. In this study, we will develop a technology to fabricate micro-structures capable of culturing cells on surfaces with various curvatures, surface shapes, and characteristics. In order to fabricate the hemispheric plastic structure(thickness $50{\mu}m$), plastic preform mold (hereinafter as "preform mold") corresponding to the hemisphere was first prepared by injection molding in order to fabricate a two - layer structure to be combined with a flat plastic film. Then, thermoplastic polymer dissolved in an organic solvent was solidified on a preform mold. As a preliminary study, we proposed injection molding conditions that can minimize X/Y/Z axis deflection value. The effects of the following conditions on the preform mold were analyzed through injection molding CAE, [(1) coolant inlet temperature, (2) injection time, (3) packing pressure, (4) volume-pressure (V/P). As a result, the injection molding process conditions (cooling water inlet temperature, injection time, holding pressure condition (V / P conversion point and holding pressure size)) which can minimize the deformation amount of the preform mold were derived through CAE without applying the experimental design method. Also, the derived injection molding process conditions were applied during actual injection molding and the degree of deformation of the formed preform mold was compared with the analysis results. It is expected that plastic film having various shapes in addition to hemispherical shape using the preform mold produced through this study will be useful for the molding preform molding technology and cast molding technology.

• Korean Journal of Computational Design and Engineering
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• v.10 no.3
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• pp.151-161
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• 2005

This paper describes the parting and Boolean operations for a pseudo-solid model of a plastic part, and their application to injection mold design. Here, a pseudo-solid model means a sheet model that looks like a solid model, but its boundary is not closed. When a solid model created in a different CAD system is imported through a standard data exchange file format, in most cases, a pseudo-solid model may be created due to tolerance or some other problems. However, most existing mold design systems based on solid modeling kernels require a complete part solid model. Therefore, mold designers have to do time-consuming healing operations to convert a pseudo-solid to solid. To eliminate or reduce the healing pre-process for mold design, in this paper, we proposed the parting and Boolean Operations on pseudo-solid part models. This paper also describes their detailed implementation and a case study.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.2
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• pp.185-192
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• 2012

The paper presents the development of a cooling circuit design system that automatically creates 3D cooling circuit on a given section plane conforming to design specifications, generates 3D solid model of cooling line segments defined on a 2D sketch plane, and verifies interference of 3D cooling channel with the molding die surface. The system was developed mainly for designing plastic injection molding die of vehicular lamp, which helps the mold designer to rapidly construct cooling circuits but also reduce designer's unintended mistakes by conforming to the dimensional design specifications. It is used by an injection molding die manufacturing company in Korea, and reported approximately 20% reduction of cooling channel design time.