• 한국CDE학회논문집
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• 제11권4호
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• pp.303-314
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• 2006

The exchange of CAD (Computer Aided Design) models between different CAD systems and to downstream applications such as manufacturing has become very important to modem industry. One serious current issue is that the process cannot automatically import existing 3-D solid models in a variety of commercial CAD formats into the process without manually re-mastering the model in current standard including "SIEP AP(Application Protocol) 203 Edition 1" To fully integrate technical data from the design agency to the shop floor, design intent and validated 3D geometry of feature based parametric CAD model should be brought into the standardized processes. To overcome this limitation, AP203 Edition 2 (Ed.2) and its related STEP parts such as Part55, Part108, Part109, Part111 and Part112 are starting to be available to handle this problem. The features in Part111 are harmonized with the machining features available in AP224. This paper is focused on two mapping technologies: CAD to Part111 mapping and Pat111 to AP224 mapping including case studios and it will provide the guideline about what should be done next in the AP203 Ed.2 to AP224 mapping. The final goal of this project is to integrate technical data from CAD to AP224 based manufacturing information through AP203 Ed.2.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2007년도 정기 학술대회 논문집
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• pp.819-824
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• 2007

Outfitting system in ship design has huge kinds of standard part. Data base of and automatic design procedure of part master should be included in ship cad in order to reduce the design time. Present study shows an process of part master DB construction of pipe equipments using 3-dimensional CAD environment Attribute and properties of part masters are chosen from JIS standard. As the schema of part masters are stored in data base, 3D geometric model is parsed from the schema.

• International Journal of CAD/CAM
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• 제6권1호
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• pp.183-192
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• 2006

A CAD/CAM system has been developed for rapid prototyping (RP) of microfluidic devices based on excimer laser micromachining. The system comprises of two complementary softwares. One, the CAM tool, creates part programs from CAD models. The other, the Simulator Tool, uses a part program to generate the laser tool path and the 2D and 3D graphical representation of the machined microstructure. The CAM tool's algorithms use the 3D geometry of a microstructure, defined as an STL file exported from a CAD system, and process parameters (laser fluence, pulse repetition frequency, number of shots per area, wall angle), to automatically generate Numerical Control (NC) part programs for the machine controller. The performance of the system has been verified and demonstrated by machining a particle transportation device. The CAM tool simplifies part programming and replaces the tedious trial-and-error approach to creating programs. The simulator tool accepts manual or computer generated part programs, and displays the tool path and the machined structure. This enables error checking and editing of the program before machining, and development of programs for complex microstructures. Combined, the tools provide a user-friendly CAD/CAM system environment for rapid prototyping of microfluidic devices.

• 한국CDE학회논문집
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• 제10권3호
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• pp.179-187
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• 2005

The usage of mixed 2D and 3D CAD data of commercial CAD systems is required in the construction practice. Sometimes 3D wireframe model is required by end-users when 2D CAD data is delivered. However, current KOSDIC can not represent 3D CAD data, because it has been developed as a 2D drawing delivery standard. Therefore, this study is to provide exchange and sharing of mixed 2D and 3D CAD data that add 3D wireframe model in the KOSDIC. To achieve this purpose, the authors have investigated the 3D CAD entities of commercial CAD systems, and have analyzed STEP standards providing 3D wireframe model. The result, the authors have extracted 3D CAD common entities based wireframe model which shall be added in the KOSDIC. This study can be beneficial by using the developed data model for heterogeneous CAD systems, and by providing the representation of mixed 2D and 3D CAD data in construction practice such as GIS, piping system, and so forth.

• 한국CDE학회논문집
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• 제18권3호
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• pp.167-176
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• 2013

It is necessary to construct equipment catalog in ship outfitting design and offshore plant design. The three-dimensional CAD data of equipment take on different level-of-detail depending on the purpose. Equipment suppliers provide CAD data with high complexity while ship designers need CAD data with low complexity. Therefore, it is necessary to simplify CAD data. However, it takes much time to simplify them manually. To resolve the issue, a system for automatically simplifying the 3D CAD data of equipment was developed. This paper presents the architecture of the system and the implementation details. In addition, experiment result using the prototype system is explained.

• 한국CDE학회논문집
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• 제19권2호
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• pp.191-201
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• 2014

A 3D CAD system that can be used on a smart device is proposed. Smart devices are now a part of everyday life and also are widely being used in various industry domains. The proposed 3D CAD system would allow modeling in a rapid and intuitive manner on a smart device when an engineer makes a 3D model of a product while moving in an engineering site. There are several obstacles to develop a 3D CAD system on a smart device such as low computing power and the small screen of smart devices, imprecise touch inputs, and transfer problems of created 3D models between PCs and smart devices. The author discusses the system design of a 3D CAD system on a smart device. The selection of the modeling operations, the assignment of touch gestures to these operations, and the construction of a geometric kernel for creating both meshes and a procedural CAD model are introduced. The proposed CAD system has been implemented for validation by user tests and to demonstrate case studies using test examples. Using the proposed system, it is possible to produce a 3D editable model swiftly and simply in a smart device environment to reduce design time of engineers.

• Journal of Computational Design and Engineering
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• 제2권4호
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• pp.253-260
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• 2015

Feature-based NC machining, which requires high quality of 3D CAD model, is widely used in machining aircraft structural part. However, there has been little research on how to automatically detect the CAD model errors. As a result, the user has to manually check the errors with great effort before NC programming. This paper proposes an automatic CAD model errors detection approach for aircraft structural part. First, the base faces are identified based on the reference directions corresponding to machining coordinate systems. Then, the CAD models are partitioned into multiple local regions based on the base faces. Finally, the CAD model error types are evaluated based on the heuristic rules. A prototype system based on CATIA has been developed to verify the effectiveness of the proposed approach.

• 한국건설관리학회논문집
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• 제5권4호
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• pp.107-114
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• 2004

4D 모델은 프로젝트 수행 이전에 다양한 공정대안을 비교 검토해볼 수 있는 기능을 제공하나 아직 그 활용이 미비한 실정이다. 이는 4D 모델의 구현에 수반되는 기술적, 경제적 문제에 기인하는 바 크다. 본 논문에서는 3D모델 정보의 활용을 통해 이러한 문제의 해결방안을 제시하였다. 즉, 기 생성된 3D 모델 정보를 가공하여 동일한 3D 모델에 대해 여러 가지 공정대안을 신속하게 생성해내는 공정 자동생성 기능을 이용함으로써 기존 4D시스템 연구에서 문제점으로 지적되었던 정보 변경에 따른 4D 모델 재구현 문제를 상당부분 개선하였다. 또한, 특정 작업기간에 따른 소요물량을 간편하게 산출해내는 물량정보 검색 기능을 통해 4D 모델의 대안검토 기능을 보완하였다. 특히 공정 자동생성 기능에서는 수평 및 수직적 우선순위의 조정을 통해 부재간, 층간 우선순위를 결정할 수 있도록 함으로써 공정순서를 신속하게 생성해낼 수 있는 환경을 제공하였다. 이것은 3D 모델이 변경되지 않은 상태에서 다양한 공정대안의 신속한 생성을 통한 비교 검토에 효과적으로 활용할 수 있으며, 3D 모델이 변경된 경우에도 4D 모델 생성을 위한 이후의 작업과정을 손쉽게 진행시켜 나갈 수 있는 장점이 있다. 아울러 3D 모델로부터 생성되는 물량정보와 공정계획 결과로부터 생성되는 일정정보를 연계시킴으로써 간편하게 일정별 소요물량 정보를 검색할 수 있게 하였다.

• 한국CDE학회논문집
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• 제10권1호
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• pp.11-16
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• 2005

CAD/CAM system may have such advantages of cost reduction, production time shortening, and product quality improvement. But current advanced versions of CAD/CAM system for 3-D NC data generation are too much expensive to purchase and too difficult to make full use for small-scale manufacturers whose main products are of 2-D simple shapes. The objective of this paper is to introduce a cost-effective way to 2-D NC data generation with a widely spread CAD software. Using VISUAL LISP in the well-known AUTO-CAD, the contents and steps of an automatic NC data generation program are presented for 2-D machining of contours and pockets. To approve the usefulness of program, a test application to a real part is exhibited also.

• 한국CDE학회논문집
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• 제8권3호
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• pp.189-200
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• 2003

This paper introduces the development of a three-dimensional jig design system for automotive body welding assembly. Recently, three-dimensional CAD systems have been introduced in the jig design area, because they reduce errors in design process and the design result can be used readily for virtual manufacturing simulation. However, to facilitate three-dimensional jig design, it is essential to customize three-dimensional CAD system for this specific design area. To accomplish this object, we first standardized the parts and units in a jig assembly, and then built the standard part library. We also developed the dedicated 3D design capabilities of jig units and a jig base. By using this system, design can be performed more intuitively, and verification and simulation of design results can be done more easily. The proposed system has been implemented using the UG/Open API of the Unigraphics system.