선형 열선절단기를 이용한 발포폴리스티렌 폼 판재 절단시 일반 절단경사각이 제품 정밀도에 미치는 영향에 관한 연구

안동규,양동열,한길영 朝鮮大學校 機械技術硏究所 2003 機械技術硏究 Vol.6 No.2

본 연구에서는 EPS 폼의 일반 경사 열선절단시 절단경사각이 제품 정밀도에 미치는 영향에 대하여 연구하였다. EPS 폼의 일반 경사 열선절단시 EPS 폼 내부 온도분포가 제품정밀도에 매우 큰 영향을 미침으로 일반 경사 열원 모델과 완전 경사 적응형 유한요소격자를 이용한 비정상상태 3차원 열전달해석을 수행하였다. 해석 결과 열선절단기 운영조건내에서 EPS 폼의 일반 경사 열선절단시 x 축 절단경사각, 즉 회전축이 열선 절단 방향과 일치하는 경사각, 이 절단폭과 모서리 용융길이 미치는 영향은 각각 0.03 ㎜ 와 0.01 ㎜ 이하였다. EPS 폼의 일반 경사 열선절단시 절단 경사각이 제품 정밀도에 미치는 영향을 실험적으로 분석/고찰하기 위하여 일반경사 절단 실험을 수행하였다. 실험 결과는 해석결과와 매우 잘 일치 하였으며, x축 절단경사각이 제품정밀도에 미치는 영향은 매우 작았다. 이 결과로부터 제안된 유한요소해석 모델의 타당성을 입증하였다. 또한, EPS 폼의 일반 경사 열선절단시 y축 절단경사각에 비하여 x축 절단경사각이 제품 정밀도에 미치는 영향이 매우 미미함을 알 수 있었다. In the present study, the influence of cutting angle on the dimensional accuracy, such as kerfwidth and the part quality. in hotwire cutting of EPS foam for the case of generally-sloped cutting with two cutting angles is investigated. Transient heat transfer analysis using a generally-sloped heat faux model arid a fully conformed mesh structure is carried out to estimate an accurate temperature field in the EPS foam. From the results of the analysis. it has heen shown that the influence of cutting angle about the x-axis in which the rotational axis is normal to hotwire cutting direction on kerfwidth and the melted length in the edge is less than 0.03 rnm and 0.01 mm in the operating range of the hotwire cutter, respectively. In order t o experimentally investigate the influence of cutting angle for generally-sloped cutting on the kerfwidth and the part quality of the cut part, inclined cutting tests with two cutting angles are carried out. Through a comparison of the computed results with the experimental results. the proposed numerical method of analysis is verified. Based on these results, it has been shown that the influence of cutting angle about the y-axis in which the rotational axis is normal with hotwire cutting direction is appreciably negligible in comparison with that of cutting angle about the x-axis.

VLM-ST 공정과 삼단역전 쾌속 툴링 공정을 이용한 3차원 제품 정형가공에 관한 연구

안동규,이상호,양동열 한국공작기계학회 2003 한국공작기계학회 춘계학술대회논문집 Vol.2003 No.-

The technical combination of RP and RT has a potential for rapid manufacturing of three-dimensional parts. In the present work, a new RP system, VLM-ST, is proposed to manufacture net shapes of 3D prototypes. ㅁ human head shape and a knob shape are manufactured by the VLM-ST apparatus. In addition, a new RT technology, which utilizes a RTV molding technique and a triple reverse process technique, is proposed to manufacture net shapes of 3D plastic parts using prototypes of VLM-ST. A plastic part of the knob shape is produced by the proposed RT technology. The combination of the proposed RP and RT enables the manufacture of a plastic knob within two days.

선형 열선전달기를 이용한 발포폴리스티렌 폼 판재 절단시 절단경사각이 제품특성에 미치는 영향에 관한 연구

안동규,양동열 朝鮮大學校 機械技術硏究所 2003 機械技術硏究 Vol.6 No.1

선형 열선, 절단기에 의한 발포 폴리스티렌 폼 절단시 절단 제품의 특성을 발포 폴리스티렌 폼 내부의 열분포에 의존적이다. 이 열분포는 열선 절단기의 절단 공정 변수인 열입력, 절단 속력 및 절단 경사각의 크기 등에 의하여 결정된다. 본 논문에서는 선형 열선 절단기에 의한 발포 폴리스티렌 폼 절단시 절단 경사각이 절단 폭과 제품 특성에 미치는 영향에 대하여 실험과 수치해석을 통하여 고찰하였다. 선형 열선 절단시 발포 폴리스티렌 폼에 발생하는 온도 분포를 예측하기 위하여 이동좌표계와 선형 체적 열원 가정을 이용한 3차원 비선형 열전달 해석을 수행하였다. 실험 및 수치해석 결과 x축 절단 경사각의 경우 선형 열선 절단기의 운영 범위내에서는 발포 폴리스티렌 폼의 절단 폭과 모서리 용융 면적에 각각 0.1㎜ 와 0.11㎟ 미만으로 영향을 미침을 알 수 있었다. During the linear hotwire cutting of expendable polystyrene foam sheet, characteristics of the cut part are highly dependent upon the thermal field in the expendable polystyrene foam sheet. The thermal field is determined by operating parameters such as heat input, cutting speed and cutting angle. The objective of this study is to investigate into effect of cutting angle on the kerfwidth, characteristics of the cut part in linear hotwire cutting of expendable polystyrene foam sheet using the experiments and the numerical analysis for the case of a single-sloped cutting. In order to predict an accurate temperature distribution, the transient thermal analysis using a moving coordinate system and the volumetric sloped heat flux model is carried out. From the results of the experiments and the analysis, it has been shown that the influence of the cutting angle about the x-axis on kerfwidth and the melted area in the edge are 0.1 mm and 0.11 mm².

내부에 피라미드 구조를 가지는 ISB 판넬의 정적 특성 분석

안동규,이상훈,김민수,한길영,김진석,정창균,양동열 한국공작기계학회 2005 한국공작기계학회 춘계학술대회논문집 Vol.2005 No.-

The objective of this research work is to investigate into static characteristics of ISB panels with the pyramidal structure as a internally structured material. In order to investigate the behavior of material deformation and frracture characteristics, several tensile tests have been carried out for the ISB panel and skin sheet. Through the results of the experiments, the mechanical properties of ISB panel and skin sheet and fracture characteristics have been obtained. In addition, the mechaical properties of the ISB panel have been compared with that of the skin sheet by the view point of a specific modulus, a specific yield strength and a specific strength. From the results of the comparision, it has been shown that the ISB panel has an excellent static characteristics.

사례기반추론기법을 이용한 선체 횡부재 구조설계 지식 표현 방법론 연구

윤덕영,양동열,차명석 朝鮮大學校 機械技術硏究所 1998 機械技術硏究 Vol.1 No.1

This paper shows the knowledge representation method for the possibility of the automation of the design and modeling of ship web frame in the level of detailed design using parametric design and case-based reasoning technique. It turns out that Case-Based Reasoning(CBR) based on casual model is successfully applied for the design automation.

단조해석을 위한 직접 행렬해법에 대한 일반적 비교

박용복,안병기,김정호,양동열 朝鮮大學校 機械技術硏究所 2004 機械技術硏究 Vol.7 No.1

유한요소해석이 소성가공 공정설계를 위하여 사용되어져 왔다. 유한요소해석은 단조공정 을 이해하기 위해서 더욱 중요해질 것이다. 복잡한 단조해석을 수행하기 위해서는 적절한 행렬해법의 제시가 해석 기법의 전반적인 효율성을 위하여 매우 중요하다. 문제 크기가 커짐에 따라 유한요소 모델과 관계한 대수방정식 해를 푸는데 소요되는 계산시간의 효율적인 처리가 필요하다. 많은 행렬기법이 개발되어져 왔고 본 논문은 이러한 목적을 위하여 멀티프란틀 해법을 제안한다. FEA(Finite Element Analysis) has been used for metal forming process design. FEA will become more and more important in understanding forging process. For large-scale forging analysis problems. the performance of a linear equation solver is very important for the overall efficiency of the analysis code. With problem size increased. the computation time needs to be reduced, which is spent on solving the system of algebraic equations associated with finite element model. Many matrix solvers have been developed and the paper has proposed multifrontal solver for this purpose.

Additive Process Using Femto-second Laser for Manufacturing Three-dimensional Nano/Micro-structures

Yang, Dong-Yol,Lim, Tae-Woo,Son, Yong,Kong, Hong-Jin,Lee, Kwang-Sup,Kim, Dong-Pyo,Park, Sang-Hu Korean Society for Precision Engineering 2007 International Journal of Precision Engineering and Vol.8 No.4

The two-photon stereolithography (TPS) process is a promising technique for the fabrication of real three-dimensional (3D) nano/micro-structures via application of a femto-second laser, In TPS, when a near-infrared ultrashort-pulsed laser is closely focused onto a confined volume of photocurable resin, only the local area at the center of the focus is cured. Therefore, real 3D microstructures with resolution under the diffraction limit can be fabricated through a layer-by-layer accumulative technique, This process provides opportunities to develop neo-conceptive nano/micro devices in IT/BT industries, However, a number of issues, including development of effective fabrication methods, highly sensitive and functional materials, and neo-conceptive devices using TPS, must be addressed for the realization of industrial application of TPS. In this review article, we discuss our efforts related to TPS: effective fabrication methods, diverse two-photon curable materials for high functional devices, and applications.

Additive Process Using Femto-second Laser for Manufacturing Three-dimensional Nano/Micro-structures

Dong-Yol Yang,Tae Woo Lim,Yong Son,Hong-Jin Kong,Kwang-Sup Lee,Dong-Pyo Kim,Sang Hu Park 한국정밀공학회 2007 International Journal of Precision Engineering and Vol.8 No.4

The two-photon stereolithography (TPS) process is a promising technique for the fabrication of real three-dimensional (3D) nano/micro-structures via application of a femto-second laser. In TPS, when a near-infrared ultrashort-pulsed laser is closely focused onto a confined volume of photocurable resin, only the local area at the center of the focus is cured. Therefore, real 3D microstructures with resolution under the diffraction limit can be fabricated through a layer-by-layer accumulative technique. This process provides opportunities to develop neo-conceptive nano/micro devices in IT/BT industries. However, a number of issues, including development of effective fabrication methods, highly sensitive and functional materials, and neo-conceptive devices using TPS, must be addressed for the realization of industrial application of TPS. In this review article. we discuss our efforts related to TPS: effective fabrication methods, diverse two-photon curable materials for high functional devices, and applications.

Innovation of Manufacturing Technology

Dong-Yol Yang 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.5

Keynote Speech(PS-03)

Dong-Yol YANG 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.5