• 연구논문집
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• s.25
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• pp.5-12
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• 1995

Mold platen are one of the most important structural components of the injection molding machine. Mold platen had been designed, and manufactured based on the experience and the method of trial and error. Recently, as the computer progress, the numerical simulation method using commercial finite element analysis code has been used to analyze the characteristics of components. It's a urgent problem to reduce the weight of mold platen while preserving the safety and reliability for the structual failure. Finite element analyses to establish basic design technologies and reducing the weight of mold platen were carried out. As result, we are obtained the about 10% reducing the weight for mold platen.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2002.02a
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• pp.180-186
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• 2002

The simulated die-casting process in which the traditional plaster casting process is combined with Rapid Prototyping technology is being used to produce Al, Mg, and Zn die-casting prototypes. Unlike in the die-casting process, molten metal in the conventional plaster casting process is fed via a gravity pour into a mold and the mold does not cool as quickly as a die-casting mold. The plaster castings have much larger and grosser grain structure as compared as the die-castings and the thin walls of the plaster mold cavity may not be completely fillet Because of lower mechanical properties induced by the large grain structure and incomplete Idling, the conventional plaster casting process is not suitable for the trial die-casting Process. In this work, an enhanced trial die-casting process has been developed in which molten metal in the plaster mold cavity is vibrated and pressurized simultaneously. Patterns for the casting are made by Rapid Prototyping technologies and then plaster molds, which have runner system, are made using these patterns. Imparted pressurized vibration to molten metal has made grain structure of castings much finer and improved fluidity of the molten metal enough to obtain complete filling at thin walls which can not be filled in the conventional plaster casting process.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.12
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• pp.124-129
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• 2001

Recently, life cycle and lead-time of products have been shortened with the demand of customers. Therefore, it is important to reduce time and cost at the step of manufacturing trial molds. High speed machining can be applied for this kind of purpose with a lot of practical advantages. In our research, several fundamental experiments are carried out to obtain machining parameters such as cutting force, machining time and surface characteristics for tool paths that are appropriate to high-speed machining. Moreover, a trial mold for an automatic transmission knob is fabricated with aluminum-7075 material. Using automatic set-up equipments, an ABS rapid prototype of a trial product of an AT knob is also manufactured with a filling process.

• Transactions of Materials Processing
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• v.30 no.3
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• pp.149-156
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• 2021

Fine blanking is a high-precision process combining principles of metal stamping and cold forming. Unlike conventional metal stamping, fine blanking uses a special triple action such as V-ring force, counter force, shearing force. This study performed the effect of pocket-shaped compression molding on the mold life of the fine blanking using the 7.4mm thick SM45C material. In order to determine the lifespan of the punch and die in the fine blanking molds, a trial mold was manufactured and various punch materials were selected to perform the mold life test. A study on the life of a fine blanking mold by applying a thick plate material was experimentally performed through a mold test.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.638-641
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• 1995

The model-technology has been conduced to a large quantity of automobile and electric products. However, many problems in mold-technology have been solved through trial and error of experts. So it has given rise to overdesign of mold and generated other problems in production line. In this paper we choosed the lower-mold of a cool chamber in refrigerator as the model of the study and mass reduced overdesigned mold. In mass reduction process, several cases in plane processing error were selected for the sample case through FEM analysis & simplicated theory analysis and each case was evaluated for mass reduction.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.119-123
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• 2005

Mold design is a knowledge-intensive decision making process where product designer, injection molding engineer as well as mold designer affect each other. Representation and management of design knowledge is a prerequisite for an intelligent design system, which aims to guide and support designer to carry out design activity in more efficient way by avoiding or minimizing unnecessary trial and errors. This paper discusses the issues in knowledge-based mold design, and describes the structure of a knowledge-based mold design system fur parts with micro features under development.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1724-1727
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• 2005

Injection molding process is one of the processes that can mold plastic product as low cost. However, manufacturing process of automobile bumper mold has lots of trial and error. Especially, desiging of a huge mold such as bumper mold is needed to establish a design standard for runner system. In this study, CAE was conducted to observe the variation of melt-flow by changing runner and gate type in automobile bumper mold as preceding study for a standard design of runner system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.355-356
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• 2006

This paper proposes an Molding error compensation method that improves accuracy with geometry information of injected parts using three-dimensional measuring instrument. a traditional mold design has been conducted by an experience-based trial and error, whereby generally the mold designer would decide the gate location and processing conditions. as a natural consequence, almost all creats inferior goods. It's just a process of trial and error and caught in a vicious circle. Due to this reason, this paper uses a three-dimensional measuring instrument, a commercial analysis package of injection molding(Moldflow, MPI) to analysis a state of flux. In addition to that axiomatic approach.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.7
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• pp.167-173
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• 2001

The simulated die-casting process in which the traditional plaster casting process is combined with Rapid Prototyping technology is being used to produce AI, Mg, and Zn die-casting prototypes. Unlike in the die-casting process, molten metal in the conventional plaster casting process is fed via a gravity pour into a mold and the mold does not cool as quickly as a die-casting mold. The plaster castings have much larger and grosser grain structure as compared with the normal die-castings and the thin walls of the plaster mold cavity may not be completely filled. Because of lower mechanical properties induced by the large grain structure and incomplete filling, the conventional plaster casting process is not suitable for the trial die-casting process to obtain quality prototypes. In this work, an enhanced trial die-casting process has been developed in which molten metal in the plaster mold cavity is vibrated and pressurized simultaneously. Patterns for the casting are made by Rapid Prototyping technologies and then plaster molds, which have a runner system, are made using these patterns. Pressurized vibration to imparted molten metal has made grain structure of castings much finer and improved fluidity of the molten enough to obtain complete filling at thin walls which may not be filled in the conventional plaster casting process..

• The Plant Pathology Journal
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• v.27 no.3
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• pp.232-341
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• 2011

Pink snow mold, caused by Microdochium nivale, is a major disease on cool season turfgrasses in golf courses in northern Unites States. The relative susceptibility of 17 commercial cultivars of three bentgrass species (creeping, colonial and velvet bentgrass) to Microdochium nivale and the aggressiveness of M. nivale eight isolates obtained from infected turfgrasses on golf courses in Wisconsin were evaluated under controlled conditions. For the field trial, susceptibility of 2 year-old 12 commercial bentgrass cultivars was evaluated after inoculating three M. nivale isolates in the fields. There were significant differences in disease severities among the three bentgrass species, particularly between tetraploids (creeping and colonial) and diploid (velvet) species, and among cultivars within each species, indicating that there are varying levels of susceptibility in species and cultivars to M. nivale. Host resistance by days of cold hardening was confirmed, by detecting the resistance by 30 days of cold hardening treatments. In field trial, susceptibility of 12 bentgrass cultivars was highly correlated to the results obtained from growth chamber experiments. The positive correlation of the susceptibility between growth chamber experiments and field trials demonstrates that the growth chamber method is a useful technique for saving time, space and labor to evaluate efficiently pink snow mold susceptibility of bentgrass cultivars. This study could be applied to evaluating susceptibility of bentgrass to pink snow mold and also predicting a prospective evaluation of bentgrass cultivars to pink snow mold in fields in a breeding program.