• Korean Journal of Computational Design and Engineering
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• v.15 no.3
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• pp.243-252
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• 2010

This paper describes a new practical simplification method for feature-based solid models. In this approach, a solid model created using feature modeling operations is first simplified by the suppression of detailed features, and then, if necessary, the model is converted to a surface model to facilitate its modification. Finally, the simplified surface model is delivered to analysis packages. The algorithm was implemented based on CATIA V.5 and applied to mid-surface generation of plastic parts for structural analysis to prove the validity and usefulness.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.6
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• pp.55-60
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• 2020

The injection molding technique is a processing method widely used for the production of plastic parts. In this study, the gate position, gate size, packing time, and melt temperature were optimized to minimize both the stress and deformation that occur during the injection molding process of medical suction device components. We used a central composite design and Latin hypercube sampling to acquire the data and adopted the response surface method as an approximation method. The efficiency of the optimization of the injection molding problem was determined by comparing the results of a genetic algorithm, sequential quadratic programming, and a non-dominant classification genetic algorithm.

• Transactions of Materials Processing
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• v.14 no.4 s.76
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• pp.375-383
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• 2005

The shear spinning process, where the plastic deformation zone is localized in a very small portion of the workpiece, shows a promise for increasingly broader application to the production of axially symmetric parts. In this paper, the three components of the working force are calculated by a newly proposed deformation model in which the spinning process is understood as shearing deformation after uniaxial yielding by bending, and shear stress, $\tau_{rz}$, becomes k, yield limit in pure shear, in the deformation zone. The tangential force are first calculated and the feed force and the normal force are obtained by the assumption of uniform distribution of roller pressure on the contact surface. The optimum contact area is obtained by minimizing the bending energy required to get the assumed deformation of the blank. The calculated forces are compared with experimental results. A comparison shows that theoretical prediction is reasonably in good agreement with experimental results

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.04a
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• pp.33-39
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• 2003

Injection molding is widely used in producing various plastic parts due to its high productivity and the demand for high precision injection molded products is ever increasing. To achieve successful product quality and precision, the design of gating and runner systems in the injection mold is very important since it directly influences melt flow into the cavity. Some defects such as weld lines and overpacking can be effectively controlled with proper selection of gate locations. In the present study, the design of gate locations in injection molding of a dashboard for automobiles was carried out with CAMPmold, a PC-based simulation system for injection molding. A dummy runner was developed to simulate a runner system in order to increase the efficiency of the analysis. The numbers and locations of gates were varied in the present investigation as that an acceptable design was obtained in terms of reduced maximum pressure and clamping force.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.4
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• pp.1033-1040
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• 1995

To simulate strength reliability and durability of ceramic parts under gas turbine application environments, particle impact damage behaviors in silicon carbide oxidized at 1673 K and 1523 K for 200 hours in atmosphere were investigated. The long-term oxidation produced a slight increase in the static fracture strength. Particle impact caused a spalling of oxide layer. The patterns of spalling and damage induced were dependent upon the property and impact velocity of the particle. Especially, the difference in spalling behaviors induced could be explained by introducing the formation mechanism of lateral crack and elastic-plastic deformation behavior at impact sit. At the low impact velocity regions, the oxidized SiC showed a little increase in the residual strength due to the cushion effect of oxide layer, as compared with the as-received SiC without oxide layer.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.9
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• pp.112-118
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• 1999

Shrinkage behavior was investigated to obtain more accurate dimensions of injected molding parts for free and restricted shrinkage conditions. various parameters for metal inserted injection process, such as thickness of resin, holding pressure and time, mo이 temperature and restriction condition of mold, were considered for the analysis of shrinkage phenomena. For numerical analysis, MOLDFLOW software was used to find the deterministic parameters of filling time, temperature, pressure and holding time. Also , experimental shrinkage effects were measured through actual injection molding process and the resin thickness was under controlled as 3 mm , 5 mm, and 7mm for the shapes of plastic gear made of Polymide(PA) and Polyxymethlene(POM). The main parameters of these injection processes were found to be holding pressure, holding time and mold temperature in the case of metal inserted molding.

• Korean Journal of Optics and Photonics
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• v.4 no.2
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• pp.145-156
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• 1993

From the optimal system specifications of optical parts in rear projection TV focused on competitive price and performances, we designed and developed projection lens which is able to be used on current broadcast standard NTSC and HDTV in common. Through the serial processes, which are initial design of all aberrations free, aspherization of the plastic lenses, optimization with tolerances and manufacturability, and athermalization, the lens was designed. The developed CRT-lens ass'y could display the 40-55 inches image and it's resolution is more than 1000 TV-lines.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.9 s.174
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• pp.173-178
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• 2005

Recently plastic parts are molded for the purpose of mass production in multi-cavity system. Therefore, designer is usually designing mold that has geometrically balanced runner lay-out for filling balance at each cavity. Although, mold is manufactured with geometrically balanced runner lay-out, there are actually filling imbalances in the cavities. These filling imbalances phenomenon are caused by complicated interaction between melt and mold. In this study, based on previous studies for filling imbalances in cold-runner mold, filling imbalances in hot-runner mold were investigated by CAE and injection molding experiments. ABS and PMMA as amorphous polymer, PA as crystalline polymer were used to compare the filling imbalances. There were different results of CAE and experiment. The filling imbalances decreased as injection rate increased without regard to kind of resins and were lower than the one of cold-runner.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.598-601
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• 2005

Plastic parts are molded for the purpose of mass production in multi-cavity system. Therefore, designer is usually designing molds that has geometrically balanced runner lay-out for filling balance at each cavities. Although, mold is manufactured with geometrically balanced runner lay-out, there are actually filling imbalances in cavities. These filling imbalances phenomenon are caused by complicated interaction between melt and mold. In this study, based on previous studies for filling imbalances in cold-runner mold, filling imbalances in hot-runner mold were investigated by CAE and injection molding experiments. ABS, PMMA as amorphous polymer and PA, PP as crystalline polymer were used to compare the filling imbalances. The filling imbalances decreased as injection rate increased without regard to kind of resins and were lower than the one of cold-runner.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.1 s.178
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• pp.159-165
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• 2006

Many rubber products are used in industrial products such as various hoses, rubber belts and oil seals etc. Especially, more then 200 rubber parts are used in the automobile, but design technology of these is largely dependent on Held experiences. These methods brought about too much time and cost in the developing procedures. However, with the help of recent rapid development of non-liner computer analysis, we can develop new sound products at low cost. Therefore in this study, optimizations of design variables such as location and number of gate in order to develop CLIP rubber product made of EPDM were performed by CAE in which Cross-WLF equations are adopted. The validity of proposed variables is evaluated by comparison with real forming results.