• Journal of KIBIM
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• v.9 no.3
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• pp.30-40
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• 2019

Extraction of fabrication documents is very important because it provides information related to tasks of fabrication and construction. Therefore, in the case of a prefabricated member such as a steel structure, it is necessary to improve the productivity of fabrication documents through 3D BIM. However, research and evidence data on direct comparison analysis of 3D BIM-based documents extraction versus 2D CAD-based documents extraction are hard to find. Thus, this study focuses on productivity analysis of 3D BIM based fabrication documents extraction. In this study, the productivity data of fabrication documents extraction for module construction of EPC project was analyzed. For the productivity analysis, a case study on the fabrication documents of Module A (1,965 sheets) and Module B (1,216 sheets) was conducted. Fabrication documents for each module include general arrangement drawing, assembly drawing, single part drawing and single plate drawing. Comparison of 2D CAD based fabrication documents extraction and 3D BIM based fabrication documents extraction, the productivity for the entire work was improved from 17 hours to 16 hours for Module A and 12 hours to 7 hours for Module B. Especially, the productivity of the assembly drawings, which occupies a large part of the fabrication documents, was improved by about 48.75% from the total time required from 281 hours to 144 hours.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.10
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• pp.552-557
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• 2015

The nanostereolithography process using a femtosecond laser has been shown to have strong merits for the direct fabrication of 2D/3D micro structures. In addition, a femtosecond laser provides efficient tools for precise micromachining owing to the advantages of a small and feeble heat effect zone. In this paper, we report an effective fabrication process of 3D micro optical and fluidic devices using nanostereolithography process composed of a dual stage system. Process conditions for additive and subtractive fabrication are examined. The Piezo stage scanning system is used for 3D micro-fabrication in unit area of sub-mm scale, and the motor stage is employed in fabrication on the scale of several mm. The misalignment between the pizeo- and motor- stages is revised through rotational transformation of CAD data in the unit domain. Here, the effectiveness of the proposed process is demonstrated through examples using 3D optical and microfluidic structures.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1259-1264
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• 2007

Microstereolithography technology has potential capability for fabrication of 3D microstructures. It evolved from conventional SLA which is one of the RP processes. In a microstereolithography process, 3D microstructures can be easily fabricated by continuously stacking 2D layer which is photopolymerized using a liquid prepolymer. Combination between biocompatible/biodegradable photocurable prepolymer and 3D complex fabrication in microstereolithography makes broad application areas such as medical, pharmaceutic, and bio devices. In particular, a 3D microneedle for transdermal drug delivery and a scaffold for tissue engineering are fabricated using this technology. In this paper, the authors address development of microstereolithography system adapted to large surface and fabrication of various microstructures. In addition, to apply human body we suggest a biodegradable 3D microneedle and a scaffold using biodegradable photocurable prepolymer.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.2
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• pp.83-88
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• 2018

Additive manufacturing (AM) technologies have attracted wide attention as key technologies for the next industrial revolution. Among AM technologies using various materials, powder bed fusion (PBF) processes and direct energy deposition (DED) are representative of the metal 3-D printing process. Both of these processes have a common feature that the laser is used as a heat source to fabricate the 3-D shape through melting of the metal powder and solidification. However, the material properties of the deposited metals differ when produced by different process conditions and methods. 17-4 precipitation-hardening stainless steel (17-4PH SS) is widely used in the field of aircraft, chemical, and nuclear industries because of its good mechanical properties and excellent corrosion resistance. In this study, we investigated the differences in microstructure and mechanical properties of deposited 17-4PH SS by PBF and DED processes, including the heat treatment effect.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.6
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• pp.686-692
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• 2012

Solid free-form fabrication (SFF) technology was developed to fabricate three-dimensional (3D) scaffolds for tissue engineering (TE) applications. In this study, we developed a polymer deposition system (PDS) and created 3D microstructures using a bioresorbable polycaprolactone (PCL) polymer. Fabrication of 3D scaffolds by PDS requires a combination of several devices, including a heating system, dispenser, and motion controller. The system can process a polymer with extremely high precision by using a 200 ${\mu}m$ nozzle. Based on scanning electron microscope (SEM) images, both the line width and the piled line height were fine and uniform. Several 3D micro-structures, including the ANU pattern (a pattern named after Andong National University), $45^{\circ}$ pattern square, frame, cylindrical, triangular, cross-shaped, and hexagon, have been fabricated using the polymer deposition system.

• Journal of KIBIM
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• v.5 no.2
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• pp.12-18
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• 2015

Bridge piers typically have circular or rectangular shapes without decorative design. Prefabrication for accelerated construction has been widely adopted in bridge structures. Cost for steel formwork is a main restriction of creative irregular shapes. 3D modelling techniques allow creative design of columns and 3D printing provides possibility to minimize the fabrication cost. In this paper, 3D design process of bridge piers was suggested by converting 2D picture into 3D decorative shape. Formwork design using 3D printed panels was also proposed and mock-up tests were conducted. Precast columns need accurate geometry control from fabrication to assembly. Laser scanning and geometry control devices were adopted. Through the digitalized process of design, fabrication and assembly, creative design of structures can be realized in reasonable cost range.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.52-53
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• 2017

Through the case study, we surveyed an applicability of digital fabrication in irregular-shaped building construction project. By digital fabrication, we mean is a precision manufacturing method has been used in aircraft, ship and car manufacturing industry. We collected construction-completed "LotteWorld Tower Podium" project data and analyzed its process in terms of construction quality andduration. The result shows that digital fabrication is considered a competitive technology that enabled to complete the project in seven months within 3mm surface curvature threshold. The digitalfabrication is expected to apply on a number of irregular-shaped building construction project.

• Journal of The Korean Digital Architecture Interior Association
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• v.12 no.1
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• pp.25-33
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• 2012

Ever since the local interior and architecture design industry adopted Digital fabrication modeling tool for its design operation in early 1990's, working environment has been changing. The Purpose of study is to analyze the digital Architecture fabrication modeling for digital design education in academy course. Digital Design Tools, Digital Space and Form, Digital Materiality and Digital Production. The Digital fabrication modeling is and important role in a traditional design process and digital design process. It is comprised of digital input devices(3D digitizer, 3D design tools) and digital output devices(cutting plotters, laser cut, CNC machines, 3D printers). Digital input devices can be shift a traditional design process to digital design process. Digital output devices are the principle of digital fabrication by CAD/CAM. Also, the result of this study provide the fundamental data for physical resources and digital design curriculum in KAAB.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.12
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• pp.59-66
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• 2019

In this study, we developed a novel laser sintering deposition system (LSDS) based on solid free-form fabrication (SFF) technology as it has the potential to fabricate complex geometries with controllable architecture for bone tissue engineering applications. The 3D biphasic calcium phosphate (BCP) scaffolds were fabricated with a pore size of 800㎛, a line width and height of 1000㎛, and an overall size of 8.2×8.2×8.0 mm3 according to the design of experiment (DOE) results. Additionally, an optimized manufacturing process using response surface analysis was established to fabricate 3D BCP scaffolds. The fabricated 3D BCP scaffolds were sintered at 950℃, 1050℃, 1150℃, and 1250℃ according to sintering processes with a furnace. As the sintering temperature increased, the porosity increased. Through the compressive strength test, the 3D BCP scaffolds sintered at 1050℃ presented good results of about 0.76 MPa. These results suggest that fabrication methods for 3D bioceramic scaffolds using LSDS may meet the basic requirements for bone tissue engineering.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.9 no.2
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• pp.145-151
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• 2015

In this paper, we proposed the fabrication methodology of orthotic device using 3D Computer-Aided Design programme and 3D printing technology based on images acquired from 3D scanner. We set the process and methodology of its fabrication method and confirmed whether it is available for clinical by fabricating four kinds of orthotic device for a patient with cerebral palsy. 3D printing technology method was indicated quantitatively and qualitatively about duration, tensile strength stronger comparing with conventional method, and we could propose that the 3D printing technology for the orthosis could be the proper method to mediate and compensate with reported problems related to orthosis.