• Journal of Korea Foundry Society
• /
• v.37 no.1
• /
• pp.1-13
• /
• 2017

The purpose of this study is to increase the part recovery rate (to more than 70%) during the casting of a ductile cast iron turbo charger housing using a heater around the riser. Before creating a casting mold, various runner and riser systems were designed and analyzed with a casting simulation analysis tool. The design variables were the heater temperature, top insulation, riser location, riser diameter and the riser shape. During the feeding from the riser to the part, the reverse model was better than the forward model. When heating the riser (above $600^{\circ}C$), solidification of the riser was delayed and the feeding effect was suitable compared to that without heating. At a higher heating temperature, less solidification shrinkage and porosity were noted inside the part. On the basis of a casting simulation, eight molds were fabricated and casting experiments were conducted. According to the experimental conditions, external and internal defects were analyzed and mechanical properties were tested. The ultimate tensile strength and elongation outcome were correspondingly more than 540MPa and 5% after a heat treatment. In addition, a maximum part recovery rate of 86% was achieved in this study.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.11
• /
• pp.7729-7735
• /
• 2015

As plastic injection mold parts is suitable system mass production making mold. So thick steering wheel parts is desirable to carry out gas injection molding. Gas injection mold is skill to inject nitrogen gas postfilling melting raw material into mold. Gas injection mold have many advantage like retrenchment of material cost, upgrading the guality. etc. It was decided gate position to minimize warpage of parts analysis injection mold process using mold flow software and incase doing gas injection mold using normal p.p material. it occur big warpage. so it is object minimizing warpage of injection parts to change p.p material containing mineral 18% and removing fingering phenomenon trouble as changing gate position. Also in case carrying out gas injection mold, I did comparison and analysis to grasp shape flow in gas setting a standard gate after flowing in raw material. Through this study, I found out changing of thickness by parts shape and it can occur warpage of parts by plastic material even though it carry out gas injection mold and it had a direct influence on trouble of parts by gate position.

• Korean Journal of Plant Taxonomy
• /
• v.39 no.1
• /
• pp.4-11
• /
• 2009

Anatomical features of both leaves and stems of the four mistletoes in Korea (Viscum album var. coloratum, Korthalsella japonica, Loranthus yadoriki, L. tanaka) and of their secondary haustorial structure within several host plants were investigated. Among the four mistletoes, there were diagnostic characters of the anatomy of leaves and stems which enabled us to distinguish the four taxa. Leaves were observed to have three distinct characters including unifacial or bifacial leaves, the number of vascular bundles in the midveins, and the level of development of sclerenchyma cells. There were four diagnostic characters of stems: overall morphology of stems in transverse view, degree of cuticle development, arrangement of vascular bundles, and features of the sclerenchyma and pith. In order to determine secondary haustorial traits, the research focused on the seven host plants of L. yadoriki and on the five host plants of K. japonica. The following features were found to be important: presence or absence of an aerial runner root, the shape of the haustorial strand and flange, the degree of penetration into host tissues, and their development of shaft in transverse view, the development both of secondary haustorial cells and short tracheid in hyphae. Korthalsella japonica and L. yadorki were clearly distinguished by these characters. The secondary haustorial forms in each host were somewhat different, due to varying degrees of development in the strength of the host plants' wood. However, qualitative characters like the final position of the secondary haustorial penetration into host tissues and the development of short tracheid cells were not only affected by the degree of development of the host plants, but also useful for the systematic study.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.18 no.10
• /
• pp.42-47
• /
• 2017

In this study,we conducted an injection molding analysis of metal powder materials for the development of flanges, which are necessary adapters for optical communication. The metal powder injection molding process is a technique for producing an injection molded article having a complicated shape by mixing ceramic or stainless powder and binders. It is used to produce products which require complex processing technology or for which the productivity is low. The purpose of this study is to minimize the manufacturing processing of products which are manufactured through existing mechanical processing procedures. For the injection molding analysis, we mixed stainless STS316 metal powder with binders at a ratio of 6 to 4 to make molding materials consisting of granular pellets. Then, three-dimensional modeling and meshing were carried out to obtain the optimal injection molding analysis conditions(molding temperature, melting temperature, injection time, injection temperature, injection pressure, packing time and cooling time). As a result of the analysis, it was discovered that the inlet became available 13.29 seconds after the first injection. Also, as the flowing and packing in the melt through the sprue, runner and gate were stable, it is expected that good molds can be manufactured.