• Journal of the Korea Institute of Building Construction
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• v.21 no.4
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• pp.293-303
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• 2021

The void PC slab has a structurally reasonable cross-section by forming the hollow section of the neutral axis that is unnecessary for bending behavior. Domestic PC factories have introduced automation equipment to produce hollow PC slabs, and are achieving hollow sections through inserts. However, since the excessive initial investment cost of the PC factory is the main factor in the increase in production cost, other alternatives are needed. Therefore, in this study, when producing hollow PC slab members, by using a rubber tube as a formwork to form an internal hollow space, it is intended to contribute to securing productivity through molding various hollow shapes, making it larger, lightweight, and enabling rapid production. To implement a hollow PC slab using a rubber tube mold, the shape of a hollow cross-section in which the tube is combined was implemented by considering the shape of the rubber tube first. In addition, to secure the concrete quality of the hollow part, the finish properties of the rubber tube mold and concrete were evaluated, and the hollow PC production process was established.

• Design & Manufacturing
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• v.1 no.1
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• pp.1-5
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• 2007

Double injection molding process is very efficient molding-method for molding the products which is consist of multi-materials. Fuel-tube holder which is necessary for automobil power train and circulation systems is composed of plastic and rubber materials to minimize the vibration and pulsation noises. In existing process, fuel-tube holder was made by the insert molding process or assembly process after molding. If fuel-tube holder is manufactured by double injection molding process, it may be realize to improve the product quality, efficiency of molding-process and retrenchment of manufacturing cost. In this study, for manufacturing fuel-tube holder by double injection molding process, the analysis of joining characteristics between PA6(polyamide 6) and TPE(thermoplastic elastomer) was executed and the double injectin mold for molding fuel-tube holder with core toggle mechanism was fabricated. Finally, fuel-tube holder was molding using fabricated double injection mold.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.203-206
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• 2008

In this study, we focused on development of the adhesive insulator using the case for solid rocket motors. Material of insulator used unvulcanized rubber based on EPDM/kevlar. In case of front insulator, preforms was made by using hot press molding, and then modified nylon film was inserted between two preforms for boots manufacturing. Rear insulator included cylinder part was embodied by only one mold with special designed and manufactured shape in the process. Boots part of rear insulator was obtained by cutting machine with hard-metal cemented carbide.