• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.8
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• pp.1242-1245
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• 2001

Plastic microlenses play an important role in reducing the size, weight, and the cost of the systems in the fields of optical data storage and optical communication. In the present study, plastic microlens arrays were fabricated using micro-compression molding process. The design and fabrication procedures for mold insert were simplified by using silicon instead of metal. A simple but effective micro compression molding process, which uses polymer powder, were developed for microlens fabrication. The governing process parameters were temperature and pressure histories and the micromolding process was controlled such that the various defects developing during molding process were minimized. The radius and magnification ratio of the fabricated microlens were 125$\mu\textrm{m}$ and over 3.0, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.1
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• pp.38-41
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• 2010

Compared to conventional molding technology, the color uniformity of light direction emitted from LED is improved with PCB type lead frame technology in which metal thin film is used and transfer molding technology which makes the density of phosphor uniform by manufacturing high density LED lamp. The light efficiency and the color uniformity of the LED are improved by molding the phosphor layer outside of chip and controlling the thickness of the phosphor layer. CIE x,y difference of LED in major axis is also improved uniformly from 0 to 90 degrees.

• Design & Manufacturing
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• v.16 no.1
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• pp.62-69
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• 2022

In the present study, the injection molding optimization of a large thick LH type elastic frames for the reduction of warpage was performed. Two kinds of fine and coarse finite element models were prepared to investigate the efficiency of analysis time and quality on simulation results. In order to derive injection molding conditions that can minimize distortion of parts, it was investigated that the effects of mold temperature, resin temperature, injection time, hold pressure switching time, holding pressure and the hold time on deformation characteristics using the design of experiments. The main influential factors on the warpage were found from the optimization simulation and the geometry data of the warpage result was converted into an initial model for injection simulation. It was shown that a coarse model with good mesh quality could be adapted for mold design since the total analysis time using the proposed model was reduced to 1/10. The suggested inversed warpage model produced the best minimized result of warpage.

• Design & Manufacturing
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• v.17 no.1
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• pp.27-32
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• 2023

In this paper, we intend to predict the mass of the spiral using CAE and machine learning. First, We generated 125 data for the experiment through a complete factor design of 3 factors and 5 levels. Next, the data were derived by performing a molding analysis through CAE, and the machine learning process was performed using a machine learning tool. To select the optimal model among the models learned using the learning data, accuracy was evaluated using RMSE. The evaluation results confirmed that the Support Vector Machine had a good predictive performance. To evaluate the predictive performance of the predictive model, We randomly generated 10 non-overlapping data within the existing injection molding condition level. We compared the CAE and support vector machine results by applying random data. As a result, good performance was confirmed with a MAPE value of 0.48%.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.10
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• pp.1549-1554
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• 2010

Recently, plastic screws have replaced metal screws because of the former's light weight, thermal and electrical insulating properties, and anticorrosion characteristics. Plastic screws are usually produced by injection molding, which involves material shrinkage during the solidification of the polymer. This shrinkage results in the degeneration of the dimensional accuracy. In the present study, the effect of injection-molding conditions on the dimensional accuracy of plastic screws was investigated through a numerical simulation of injection molding; on the basis of this simulation, we could determine the mold-design parameters. The design of experiment was applied in accordance with the numerical analysis in order to optimize the injection-molding conditions with a view to improving the dimensional accuracy of the precision plastic screw.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.1039-1042
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• 2000

This research will deal with Innovative manufacturing technology for milli-structure manufacturing technology which is located betweon the traditional manufacturing technology for macro-sized structure and the recently emerging manufacturing technology for micro-scaled structure such as MEMS. There are four fields in this research, which are micro-sheet metal forming technology, micro-bulk forming technology micro-molding technology and micro die making technology. As a project for new-technology in next generation, this research will be carried out through three terms and each term and be composed of three years.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.6
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• pp.809-815
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• 1998

This study has been performed to investigate MRR(metal removal rate) surface roughness with various pulse-on duration using the copper and graphite electrode according to the electrode size on the heat treated STD 11 which is extensively used for metallic molding steel in the EDM. The results obtained are as follow ;a)MRR increases a lot when pulse-on duration is 100 $\mu{s}$ or less but MRR has little difference with pulse-on duration of 100 $\mu{s}$ or more b) According to the increase of Pulse-on duration the large the electrode size the more MRR c) Safe discharge is needed to make maximum of MRR and the metallic organization must be complicated for discharge induction. d) Actual machining time is longer than theoretical machining time at the short pulse-on duration because of skin effect of current. e) Graphite electrode needs the larger electric discharge energy than copper electrode to remove remained chips completely.

• Journal of the Korea Society of Computer and Information
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• v.22 no.10
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• pp.1-7
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• 2017

In this paper, the separation force measuring system is developed. The separation force aries due to adhesive strength between semiconductor epoxy molding compound(EMC) and the metal plate in semiconductor formed plate. In general, when removing the metal plate in semiconductor formed plate from semiconductor epoxy molding compound, excessive strength can result in a increase in semiconductor defect rates, or conversely, if too little force is exerted on the metal plate in semiconductor formed plate, the semiconductor production rates can decrease. In this study, the design criteria for the selection of the AC servo motor, the role of the ball screw, the relationship between the load cell and the ball screw, and the rate of deceleration are given. In addition, minimizing the reject rate of semiconductors and maximizing the semiconductor production rate are achieved through the standardization of the collected separation force data measured by the proposed system.

• Design & Manufacturing
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• v.13 no.2
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• pp.17-21
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• 2019

In this study, selective laser sintered 3D printing mold core and metal core were used to investigate the difference of the thickness shrinkage from the gate of the injection molded part at a constant interval. SLS 3D printing mold core was made of nylon-based PA2200 powder and the metal core was manufactured by conventional machining method. As the PA2200 powder material has low strength, thermal conductivity and high specific heat characteristics compared with metal, molding conditions were set with the consideration of molten temperature and injection pressure. Crystalline resin(PP) and amorphous resin(PS) with low melting temperature and viscosity were selected for the injection molding experiment. Cooling time for processing condition was selected by checking the temperature change of the cores with a cavity temperature sensor. The cooling time of the 3D printing core was required a longer time than that of the metal core. The thickness shrinkage of the molded part compared to the core depth was measured from the gate by a constant interval. It was shown that the thickness shrinkage of the 3D printing core was 2.02 ~ 4.34% larger than that of metal core. In additions, in the case of metal core, thickness shrinkage was increased with distance from the gate, on the contrary, in the case of polymer core showed reversed aspect.

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