• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.11 no.3
• /
• pp.92-97
• /
• 2012

Injection mold is a manufacturing process used to produce parts of complicated shape at a low cost. Many factors affect the quality of injection molded part during injection molding process. A study on the optimization of injection mold is progressed by using a simulation software like Moldflow. Filling, packing and cooling phases of injection molding processes are analyzed according to the mold design considering the shrinkage of molded part, the degree of filling rate and the wearing of a mold. Taguchi method is applied to analyze the significance of processing parameter and the dynamic characteristics according to the variation of processing parameters. From the results, the mold temperature and packing pressure influenced the shrinkage of injection molded part.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.19 no.5
• /
• pp.75-81
• /
• 2020

Multistage hot forging process enables mass production of various parts at a high speed, wherein, it is important to design the forging steps in an optimal way. Finite element methods are widely applied for optimizing the forging process design; however, they present inaccurate results due to the rapid change in the mold temperature during multistage hot forging. In this study, the temperature distributions of the mold in a steady state were calculated via heat transfer analysis during mold cooling. The flow stress and friction coefficient of the material were measured according to the temperature and were applied for numerical analysis of the multistage hot forging process. Eventually, the accuracy of the analysis results is verified by comparing these results with the experiments.

• Transactions of Materials Processing
• /
• v.16 no.1 s.91
• /
• pp.61-66
• /
• 2007

Powder injection molding(PIM) is widely used for many parts in the field of automotives, electronics and medical industries, due to the capability of net shaping for complex 3-D geometry. Powder injection mold design for the dental scaler tip, a component of medical appliance, was presented. In comparison with conventional machining process, powder injection molding has many advantages, specially in price and dimensional stability, for molding dental scaler tip which has complex geometry. Both product design and mold design for dental scaler tip were presented. A PIM feedstock was made of stainless series(17-4PH, 316L, 440C) powder and a wax based binder. The 'rapid mold' concept was applied to manufacture the various forms and materials of dental scaler tip including vibration characteristics.

• The Plant Pathology Journal
• /
• v.19 no.2
• /
• pp.102-105
• /
• 2003

Gray mold severely occurred up to 50% in freesia and gladiolus grown in the fields and greenhouses in Korea from 1998 to 2000. Symptoms appeared as spot and blight on loaves and flowers of infected plants. A total of 25 isolates was obtained from infected plant parts. All the isolates were identified as Botrytis gladiolorum based on their morphological and cultural characteristics. Gray mold symptoms similar to those observed in the fields and greenhouses were induced on the plants of freesia and gladiolus by artificial inoculation with four isolates of the fungus. This is the first report of gray mold of freesia caused by B. gladiolorum in Korea.

• Design & Manufacturing
• /
• v.2 no.2
• /
• pp.33-37
• /
• 2008

This paper describes the optimization of injection molding conditions to minimize sink marks. Sink marks, which refer to a small depression on the surface opposite a thick wall thickness, are often encounted in injection molded plastic parts. Part geometry, material properties and processing conditions during injection molding can affect the sink mark depth. We designed the runner system which is possible balanced filling to cavities using CAE program and then obtained optimal processing conditions by Taguchi's Robust Design technique. By actual injection molding using optimized mold and molding conditions, it confirmed that sink mark depth decreased zero compared to 1mm level in the conventional mold and process.

• Journal of the Korea Safety Management & Science
• /
• v.6 no.4
• /
• pp.183-193
• /
• 2004

The injection mold industry has strong relationship with many other industries. In the injection mold industry, the harmonious collaboration of the order-making companies, the mold-making companies, and the molded-parts making companies, which are distantly located, is very important. In this study, a web-based collaboration system is developed for the purpose. It offers the criterion to select appropriate production companies. It also tries to minimize the production cost of the mold design by distributing and evaluating the design information. The developed system is constructed using various recent web-programming tools.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2009.10a
• /
• pp.99-102
• /
• 2009

The recent LCD TV market has made efforts to produce thinner, brighter, and clearer products, and experienced the rapid light source replacement from a line source of light CCFL to a point source of light LED. In particular, LGP(Light Guiding Panel) among key parts composing BLU(Back Light Unit) has limits of the injection molding technology as well as the mold design, its processing and manufacturing technology so that it is hard to produce large LGP over 40 inch. To produce large light-guide panels over 40 inch under the injection molding process, a mold 3D model was developed in the design process before manufacturing a mold and structure unification was processed through CAE analysis. As a result, it was possible to construct the mold design process, and it is expected to manufacture the optimized mold by applying the mold design and manufacturing process of large-scale rapid injection-compression molding that will be produced in the future.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.10
• /
• pp.4392-4397
• /
• 2012

In this study, we used the commercial package (Unigraphics) to construct a junction box cable car when laser plastic parts have been processed using urethane resin(TSR-755) as a starting mold material. After construction, we carried out the filing, packing, cooling, and deforming analyzation using Injection Molding Analysis (Simpoe-Mold) to determine the gate positioning and automatic cooling cycle through the examination. The results show that inserting into the injection mold after processing ceramic has reduced the time of thermal conductivity of molding and cooling; and quick selection of gates and cooling lines could possibly cause an improvement of productivity.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.7 no.4
• /
• pp.738-742
• /
• 2006

In this study we developed the electrical heating mold core by applying three different heating methods. In order to find out the optimal heating method, we observed the temperature profiles with time. We also injection-molded the parts by the heating methods and investigated the shrinkage ratio, density, surface roughness and weld-lines. The temperature rise time and cycle time showed the promising results for commercial applications(the rise time is $130^{\circ}C$/14sec, the cycle time is 55sec). By comparing with the conventional and gas flame heating method, the parts by this method were proven to have good qualities. The shrinkage ratio reduced by 5.1%, the density increase by 2.66%, the smoothness increased about 3 times, and the weld-line did not observed by naked eyes.

• Design & Manufacturing
• /
• v.14 no.4
• /
• pp.11-16
• /
• 2020

In this study, forming of carbon composite parts was performed using an injection/compression molding process. An impregnation of matrix is determined by ability of wet and flow rate between the matrix and reinforcement. The flow rate of matrix passing through the reinforcements is a function of permeability of reinforcement, a viscosity of matrix and pressure gradient on molding, and the viscosity of the matrix depends on the mold temperature, molding pressure and shear strain of matrix. Therefore, compression molding experiment was conducted using a heating mold in order to confirm the possibility of matrix impregnation. The impregnation of the matrix through the porosities between the woven yarns was confirmed by the cross-sectional SEM image of compression molded parts. An injection molding process was also performed at a short cycle time, high molding pressure and low mold temperature than those of compression experiment conditions. Deterioration of impregnation on the surface of molded parts were caused by these injection conditions and it could be the reason of decreasing the maximum tensile strength. In order to improve impregnation of matrix on the surface, injection/compression molding and insert-over molding were applied. As a result of applying injection/compression molding and insert-over molding, it was shown that the improvement of impregnation on the surface and the maximum tensile strength was increased about 2.8 times than the virgin matrix.