• Composites Research
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• v.17 no.4
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• pp.47-52
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• 2004

This paper established the procedure to fabricate the MWNT/PMMA nanocomposite by using together with injection molding and film casting processes. The fabrication process made it possible for MWNTs to be well dispersed in the PMMA matrix and also it could maintain the well-dispersed state effectively. And the mechanical material properties and SEM images of the fractural surface were observed. Moreover, a surfactant was used to disperse MWNTs more effectively and mechanical material properties were also investigated.

• Journal of the KSME
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• v.32 no.1
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• pp.18-27
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• 1992

섬유강화 플라스틱을 시초로 복합재료가 상업적으로 생산, 판매되기 시작한지 어언 30여년이 되었다. 뛰어난 기계적 . 화학적 특성을 바탕으로 오늘날 복합재료는 신소재의 한 분야로 굳게 자리잡고 있다. 설계, 성형, 분석기술의 발전과 아울러 유리섬유 복합재료 이후에 특성이 뛰어난 복합재료 소재들이 개발되고 있어 복합재료의 응용범위를 더욱더 넓히고 있다. Boron, carbon, aramid섬유의 개발은 첨단 복합재료의 개발을 가능케 했으며 군용, 우주기기의 개발로 얻어진 결과들은 민간 항공기 또는 스포츠, 레저 분야에 많이 이용되고 있다. 민간 항공기의 많은 부분에 첨단 복합재료로 된 부품들이 사용되고 있으며 복합재료로된 골프채, 낚시대, 테니스채 그리고 스키 등을 우리 주변에서 손쉽게 찾아볼 수 있다. 이 글에서는 고분자 기지 복합재료를 중심으로 그 성형법 및 응용에 대하여 논하고 기타 특수용도 복합재료에 대해서 약술하고자 한다.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.6
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• pp.76-81
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• 2021

A plastic noise barrier is a structure installed to minimize noise, and it is composed of the main plate, sound-absorbing plate, and sound-absorbing material. Plastic noise barrier structures have several advantages compared to other products, such as light weight, anticorrosion, durability, easy assembly, rapid construction, and low costs. In this study, the main and sound-absorbing plates were manufactured through extrusion molding, and the sound-absorbing plate was finished with a press to improve the conventional injection molding. Extrusion molding dies and punch dies were designed, and a profile extrusion-molding system was developed. Thus, inexpensive and efficient sound-absorbing and main plates can be produced, and the noise barrier structure can be assembled rapidly. Additionally, a noise barrier structure with extended service life and excellent quality can be constructed by creating uniform free space to accommodate increased temperatures after assembly and installation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.9
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• pp.1167-1173
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• 2010

Forming of a silencer case was studied using a virtual tryout method. First, the appropriate blank shape was determined by cutting off the undeformed part of the rectangular blank. Then drawbeads were designed such that the formation of wrinkles on the shoulders and pipe connection can be prevented. Finally, the shape bead was designed such that fracture and formation of wrinkles around the pipe connection can be avoided. The prototype of the silencer case was manufactured in accordance with the conditions of the virtual tryout process. By comparing the formability of the prototype with the results of finite element analysis, it was found that the forming of the prototype agreed well with the results of analysis.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.11
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• pp.1507-1514
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• 2011

Injection molding is the most commonly used process that uses plastic material. Today, the uses of plastic material are continuously increasing, and the range of application is also being extended by the development of novel materials. An inline skate consists of 4 components: the boot, frame, wheel and brake. Among these components, the frame is the most critical. The injection formability for a variety of injection materials for inline skate frames was studied. We also studied the injection formability of the product for various sizes of the runner and gate. In this study, injection molding analysis was performed using MOLDFLOW, and structural analysis was performed using ANSYS.

• Journal of the Korean Ceramic Society
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• v.36 no.3
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• pp.266-273
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• 1999

본 연구에서는 겔캐스팅법의 제조공정 확립을 위하여 분산제의 분자구조가 질화규소 슬립의 점성특성 및 성형체의 상대밀도와 기계적 특성에 미치는 영향을 조사하였다. 슬립과 겔캐스팅 성형체의 제조방법은 기보고된 방법과 동일하게 하였다. 그 결과, 겔캐스팅 슬립의 점성은 분산제의 분자구조와 모노머와 분산제의 구성비율에 크게 의존하였다. PMAA 분산제를 사용한 슬립의 점성은 PAA 및 PAAm 분산제 보다 높은 점도를 나타내었다. 성형체의 상대밀도는 슬립의 농도에 크게 의존하였으며, 분산제양과 모노머의 양변화에는 그다지 변화가 없었다. 그리고, 겔캐스팅 성형체의 기계적 특성은 크게 모노머의 농도에 의존하였으며, 분산제양과 슬립의 농도에는 큰 변화가 없었다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.7
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• pp.1076-1086
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• 2003

The effect of a rubber mould on densification behavior of aluminum alloy powder was investigated under cold isostatic compaction. A thickness of rubber mould and friction effect between die wall and rubber mould were also studied. The hyperelastic constitutive equation based on the Ogden strain energy potential was employed to analyze deformation of rubber. The elastoplastic constitutive equation of Shima and Oyane and that of Lee on densification were implemented into a finite element program (ABAQUS) to simulate densification of metal powder for cold isostatic pressing and rubber isostatic pressing. Finite element results were compared with experimental data for densification and deformation of aluminum alloy powder under isostatic compaction.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1142-1147
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• 2003

The formability of sheet metal appears better in incremental forming than in conventional forming. in this study, the effect of process parameters - tool type, tool size, feed rate, friction at the interface between tool and sheet, plane-anisotropy of sheet - on the formability was investigated by experiments and FEM analyses. it was found that the formability is improved when a ball tool of a particular size is used with a small feed rate and a little friction. Due to the plane anisotropy, the formability differs according to the direction of the tool movement. in this paper, details of the experimental procedures and the results obtained from the study are discussed.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1332-1336
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• 2003

An experimental method is presented to maximize the replication quality of UV-molded micro-optical components. It is important to maximize the replication quality, because one can obtain the replicated micro-optical components with desired properties by accurate control of the shape. In the present study, a simple technique to avoid micro-air bubbles was first suggested. The effects of the UV-curing dose and the compression pressure on the replication quality of UV-molded structure were examined experimentally. Finally, as a practical application of the process design method, microlens arrays with diameters between 8 ${\mu}m$ and 96 ${\mu}m$ were fabricated by the present method, and the replication quality and the optical properties of the replicated microlens were measured and analyzed.

• Journal of Power System Engineering
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• v.9 no.4
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• pp.83-89
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• 2005

Molding shrinkage is one of the problems to be solved in conventional injection molding. Despite many trying-out has been to solve it, intrinsic cause of shrinkage such as orientation and thermal exchange between melt and mold has not been solved yet. For reducing shrinkage and residual stress on molding, injection compression molding process was invented. In this study, experiments about effects of injection compression molding's parameters on shrinkage of PMMA molding were conducted and compared with conventional injection molding's shrinkage. Before the injection compression molding experiment, molding shrinkage rate was predicted by analyzing pvT diagram and was compared with the results of experiment. The shrinkage rate of injection compression molding was lower than convention injection molding's one which was different from the predicted shrinkage. The reason was observed that the experimental mold was not a proper type for injection compression, flowing backward of melt into nozzle and unreasonable mechanism of injection molding machine.