• Journal of Korea Foundry Society
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• v.20 no.6
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• pp.400-406
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• 2000

Computer simulation for the predictions of casting defects is very important to produce high quality castings with less cost. Complicate shaped Al solenoid housing part was selected to be cold chamber die cast and a numerical simulation technique was applied for the optimization of the chill vent position and gating. A first design led to insufficient central flow. This flow left the last filled areas falling into the inner portion of the part. And last filled area did not fit the chill vent position. So these resulted in a high possibility of air entrapment in the casting and the design was not proper for the part. The design was improved by using a proper gating system, a more chill vent and proper overflow positions. New design provided a homogenous mold filling pattern and the last filled areas that being located at the overflow and chill vent. Casting plan which produce good quality solenoid housing part was established by using the computer simulation.

• Composites Research
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• v.28 no.2
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• pp.46-51
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• 2015

In this study, structural design and analysis of the automobile bonnet is performed. The flax/vinly ester composite material is applied for structural design. The Vacuum Assisted Resin Transfer Molding-Light (VARTML) manufacturing method is adopted for manufacturing the flax fiber composite bonnet. The VARTML is a manufacturing process that the resin is injected into the fly layered-up fibers enclosed by a rigid mold tool under vacuum. A series of flax/vinyl ester composite panels are manufactured, and several kinds of specimens cut out from the panels are tested to obtain mechanical performance data. Based on this, structural design of the automobile bonnet is performed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.449-450
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• 2006

Development of a feed drive system with high speed, positioning accuracy and thrust has been an important issue in modern automation systems and machine tools. Linear motors can be used as an efficient system to achieve such technical demands. By eliminating mechanical transmission mechanisms such as ball screw or rack-pinion, much higher speeds and greater acceleration can be achieved without backlash or excessive friction. However, an important disadvantage of linear motor system is its high power loss and heating up of motor and neighboring machine components on operation. For the application of the linear motors to precision machine tools an effective cooling method and thermal optimizing measures are required. In this paper presents an investigation into a thermal behavior of linear motor cooling plate. FVM employed to analyze the thermal behavior of the linear motor cooling plate, using the ANSYS-CFX.

• Laser Solutions
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• v.14 no.2
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• pp.24-29
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• 2011

The design of a telecentric f-${\theta}$ lens with a field of view (FOV) $30^{\circ}$ and an effective focal length of 1000mm is presented. The optical stop is placed at the front plane and the design is based on a geometric ray tracing technique, and the designed system consists of a series of convex and concave lenses. The designed f-${\theta}$ lens showed a considerable reduction in weight with a simplified structure and resulted in a good performance in the designated FOV. Detail analysis of rays is also presented. 653nm (red laser), 586nm (green laser), and 468nm (blue laser) were simulated as a light source and image illuminating source. The developed optical design requires 7 pieces of lenses made of SF1, N-FK56, N-LAK33, and BK7 glass materials. With optimal parametric design, the effective focal length was calculated to be 974.839mm which is very close to the initial design target. For the manufacturing purpose, the dimensions of lens curvature and thickness were truncated with error ranging 0.1% to 3.2%. As a result, the overall error was calculated to be 3.2% which can be still tolerable for display, laser material, and machining processing.

• Journal of the Korea Safety Management & Science
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• v.15 no.2
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• pp.71-77
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• 2013

The accident which is caused by the press work remains a Permanent obstacle in worker's hand or arms, the disaster ratio is high and the fatal case is many. Mainly Like this accident occurs because the hand to enter with inside of the press die, therefore, basic countermeasure is the safety press. In order to prevent access to mechanical moving part by the hand or any part of the body, it is important to making a safety die design Structurally. It presents the design of the safety press die with suitable structure in the Product's attribute which it had shown in samples, There is a possibility of being difficult because the attribute of safety die design that had present all the productions from research does not agree each other. but because the representative process which is used most at sample had designed, If you were imitates with safety die design base which is presented from this research, It comes to be thought to be the part which can are used at the various sides.

• Journal of the Korean Society for Heat Treatment
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• v.24 no.4
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• pp.203-208
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• 2011

Recently, from general machine parts and automobile parts using carbon steel to a mold, there has been efforts for improving durability and attrition resistance of these parts. Especially, heat treatment with laser which works fast and automatically can be used for the mass production with high quality. Moreover, local heat treatment can be used to handle with complex and precise parts. Accordingly, we analyzed hardening characteristics of carbon steel using the finite element method and compare the experimental results to have more reliability. We also proved the cause of thermal deformation with temperature and stress distribution by heat treatment. After these analysis and experimental, we found that each maximum hardness of the two tests was 728 Hv and 700 Hv, on condition of $1050^{\circ}C$ heating temperature, and 2 mm/sec laser speed. We also found that difference of surface stress-distribution was occurred, and this makes deformation mode up after heat treatment.

• 한국금형공학회:학술대회논문집
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• 2008.06a
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• pp.203-208
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• 2008

Recently, the modern society in development and industrial growth is investing a lot of time and much effort to improvement and environment of life quality. Thus, the casting tape which uses environmentally friendly and human body friendly water hardening process Polymer is rapidly substituted for the gypsum cast product which has been plentifully used in medical treatment. Until currently, prior researches have a tendency to focusing the analysis about chemical creation expense and reaction quality rather than the issue about optimization of the process for this polymerization. In the polymerization process which has been accomplished with actual same chemical creation expense, there has been a problem which is the possibility of getting a different result. This is because the optimization of respectively control factors is not accomplished which affect at polymerization process. Therefore, this research sees the chemical qualities of casting tape Polymer, consequently selects the polymerization process which is suitable. And, by using a experimental design, this research will evaluate the affects which the respective factors have on remaining NCO and viscosity. futhermore, this research will carry out the process optimization which can get the above results.

• 한국금형공학회:학술대회논문집
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• 2008.06a
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• pp.61-66
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• 2008

The hydraulic system have been used much in a heavy machine which high power source is desired. In the case of the heavy press machine and the injection molding machine, the use of the hydraulic power is essential especially for increasing productivity and getting the good products. Because the hydraulic circuit is very complex and the system parameters are uncertain, the development of the simulation model for hydraulic system is not easy in the heavy machine. In this case, Many researchers have used a commercial program for analysis and development in a major field of study. In this paper, the aim is to develop the simulation model of the hydraulic system with various commercial program for trajectory tracking. And adaptive control method is applied to the simulation model for the trajectory tracking of a cylinder motion. Load on the cylinder is modeled in ADAMS program, the hydraulic circuit including pump, spool valve and cylinder is modeled in AMESim program and a controller is designed in MatLab/simulink program. The suggested model is applied for the tracking of a cylinder motion, and through computer simulation, its trajectory tracking performance is illustrated.

• Journal of the Society of Naval Architects of Korea
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• v.50 no.5
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• pp.349-354
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• 2013

The blades of flexible propellers are formed by overlaying and adhering many layers of thin glass-fiber fabric sheets, are compressed and dried in the rigid mold. The current manufacturing process can not avoid the rather irregular deformation of the blades composed of non-isotropic non-uniform fabric structures, and inevitably introduces the different shape-forming errors between blades. In this paper, several flexible model propellers are precisely measured with three-dimensional optical instrument and compared with the original design geometry. The model propellers with the as-measured geometry are evaluated with the lifting-surface-theory-based propeller analysis code. The open-water performance are presented and discussed. The importance of the manufacturing accuracy is addressed to be able to apply the flexible propellers for propulsion of marine vehicles.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.361-364
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• 2009

The cooling system optimization for injection molds was studied with a response surface method in the previous research. It took so much time to find an optimum solution for a large product due to an extensive amount of calculation time for the CAE analysis. In order to use the optimization technique in the actual design process, the calculation time should be much reduced. In this study, we tried to reduce the number of design variables with the concept of the close relationship between the depth and the distance of cooling channels. The optimum ratio of the distance to the depth of cooling channels for a 2-dimensional problem was 2.0 so that the optimum ratio was again sought out for 4 industrial products. The major cooling effect of the injection molds for large products rely on baffle tubes. The optimum ratio of the distance to the depth for baffle tubes was 2.0 for the large products. The result enables us to reduce the number of the design variables by half in the cooling system optimization problem.