• Design & Manufacturing
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• v.10 no.3
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• pp.8-13
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• 2016

Despite technological advance, there have been several troubles in photo reaction injection molding (photo RIM) to produce ultra thin light guide panels (LGPs). In this study, micro leakage problem at cavity edge during photo RIM was investigated numerically. In order to obtain optimal processing conditions, we regulated inlet pressure of injected resin at the cavity edge and figured out micro leakage behaviors. At low inlet pressure (less than 100 Pa), though the micro leakage problem was not occurred, another problem, short shot due to not enough driving force, was appeared More than 1,000 Pa of the inlet pressure, injected resin was rapidly leaked through the micro gap at the cavity edge. Finally, we obtained optimal inlet pressure around 600 ~ 1,000 Pa. At this region, injected resin fully filled the cavity without micro leakage behavior. Based on the present study, further comparative investigations with experimental photo RIM should be performed to find optimal processing conditions for produce ultra thin LGPs.

• Design & Manufacturing
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• v.2 no.1
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• pp.51-56
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• 2008

Recently, the demand of high-productivity injection mold increases since the consumption of packaging grows in the world. Stack mold is composed of more than two molds and it has very high productivity and economic efficiency. In this study, stack mold was developed to improve productivity of vehicle fixed weather strip with TPV materials and to investigate the characteristic of injection molding using CAE.

• Transactions of Materials Processing
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• v.15 no.1 s.82
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• pp.65-70
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• 2006

In recent industry, with the miniaturization and high-precision of machine part, the development of mold manufacturing technology for mass production is accompanied by the development of new technology such as IT and BT In this study, the spiral type injection mold with a $200{\mu}m$ thickness is made to. investigating the influence of injection molding parameter and the flow length is measured through an experiment. Besides, Taguchi method is used in this experiment and the obtained data are analyzed using ANOVA method.

• Design & Manufacturing
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• v.2 no.1
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• pp.45-50
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• 2008

Micro channel is to fabricate desired pattern on the polymer substrate by pressing the patterned mold against the substrate which is heated above the glass transition temperature, and it is a high throughput fabrication method for bio chip, optical microstructure, etc. due to the simultaneous large area patterning. However, the bad pattern fidelity in large area patterning is one of the obstacles to applying the hot embossing technology for mass production. In the present study, stamper of cross channel with width $100{\mu}m$ and height $50{\mu}m$ was manufactured using UV-LiGA process. Micro channel was manufactured using stamper manufactured in this study. Also replicability appliance was evaluated for micro channel and factors affected replicability were investigated using Taguchi method.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.444-447
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• 2005

In recent industry, according to pursuit the miniaturization and high-precision of machine part with development of new technology as If, BT the development of mold manufacturing technology for mass production is accompanied. In this study, after executing the injection molding process of micro structure on the plate which the aspect ratio is 10, the characteristic of each molding condition is investigated by observing the filling height.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.45-46
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• 2006

In recent years, micro powder injection molding $(\mu-PIM)$ is being explored as an economical fabrication method for microcomponents in microsystems technology (MST). Technical and economic comparison was performed for $\mu-PIM$ processes. Molding experiment and simulation during the filling process were performed to evaluate several different geometries and processing conditions. The influence of material parameters and process conditions on mold filling were examined as a function of features size using microchannels as an example. It was found that the heat conductivity and viscosity of feedstock, geometry and mold temperature were the most critical parameters for complete filling of micro features.

• Korea-Australia Rheology Journal
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• v.19 no.3
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• pp.171-176
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• 2007

LCD-BLU (Liquid Crystal Display-Back Light Unit) of medium size is usually manufactured by forming numerous dots with $50{\sim}300\;{\mu}m$ in diameter by etching process and V-grove shape with $50\;{\mu}m$ in height by mechanical cutting process. However, the surface of the etched dots is very rough due to the characteristics of the etching process and V-cutting needs rather high cost. Instead of existing optical pattern made by etching and mechanical cutting, 3-dimensional continuous micro-lens of $200\;{\mu}m$ in diameter was applied in the present study. The continuous micro-lens pattern fabricated by modified LIGA with thermal reflow process was tested to this new optical design of LGP. The manufacturing process using LIGA-reflow is made up of three stages as follows: (i) the stage of lithography, (ii) the stage of thermal reflow process and (iii) the stage of electroplating. The continuous micro-lens patterned LGP was fabricated with injection molding and its test results showed the possibility of commercial use in the future.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.74-77
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• 2009

Demands for high quality and productivity of precision mechanical parts are increasing greatly nowadays due to the rapid growth of information technologies and convergence industries. Therefore, core technologies for fabrication of precision mechanical parts are the fundamental issues, which are the precision machining, micro powder injection molding technologies, MR polishing, micro polymer processes, micro actuation modules and so on. These technologies are directly related to the mass production of high functional devices and machineries. Therefore, this study investigates the fabrication technologies of micro precision molds for advanced devices for possible commercialization in a near future.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.209-210
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• 2013

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.388-390
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• 2003

Paste micro-injection molding process was applied for fabrication of barrier ribs of PDP in an attempt to reduce processing steps and materials loss during the processing. For the paste, a thermally curable one was used and for the mold, a polymeric soft mold was used. It was demonstrated that the micro-molding process can be used successfully in producing barrier ribs of PDP.