• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.188-189
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• 2021

The technology of manufacturing freeform molds with S-LOM based 3D printer has advantages in the production period and the curvature range. However, there is no any support tool about productivity analysis of S-LOM technology because S-LOM technology is early-stage technology. There can be problems about increase of construction time and cost without any decision support tool like productivity analysis models etc. Therefore, in this study, the productivity analysis simulation model for freeform formwork based on S-LOM technology was developed using ARENA software. The process and logic of manufacturing freeform molds can be easily visualized in this model. Futhermore, the resource like labor, equipment and material can be easily optimized with this model. As a result, it can contribute to preventing the increase of construction time and cost in formwork with further productivity analysis.

• Advances in concrete construction
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• v.8 no.2
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• pp.155-163
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• 2019

The objective of this study was to derive a cementitious material for three-dimensional (3D) concrete printing that fulfills key performance functions, extrudability, buildability and bondability for 3D concrete printing. For this purpose, the rheological properties shown by different compositions of cement paste, the most fundamental component of concrete, were assessed, and the correlation between the rheological properties and key performance functions was analyzed. The results of the experiments indicated that the overall properties of a binder have a greater influence on the yield stress than the plastic viscosity. When the performance of a cementitious material for 3D printing was considered in relation with the properties of a binder, a mixture with FA or SF was thought to be more appropriate; however, a mixture containing GGBS was found to be inappropriate as it failed to meet the required function especially, buildability and extrudability. For a simple quantitative evaluation, the correlation between the rheological parameters of cementitious materials and simplified flow performance test results-time taken to reach T-150 and the number of hits required to reach T-150-in consideration of the flow of cementitious materials was compared. The result of the analysis showed a high reliability for the correlation between the rheological parameters and the time taken to reach T-150, but a low reliability for the number of hits needed for the fluid to reach T-150. In conclusion, among several performance functions, extrudability and buildability were mainly assessed based on the results obtained from various formulations from a rheological perspective, and the suitable formulations of composite materials for 3D printing was derived.

• Journal of the Earthquake Engineering Society of Korea
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• v.27 no.6
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• pp.321-330
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• 2023

In this study, the structural performance of the specimen fabricated through 3D printing was evaluated through monotonic loading experiments analysis to apply to 3D printed structures. The compression and flexural experiments were carried out, and the experimental results were compared to the finite element model results. The loading directions of specimens were investigated to consider the capacity of specimens with different curing periods, such as 7 and 28 days. As a result, the strength tended to increase slightly depending on the stacking direction. Also, between the 3D-printed panel composite and the non-reinforced panel, the bending performance depended on the presence or absence of composite reinforcement.

• Fashion & Textile Research Journal
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• v.21 no.3
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• pp.267-276
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• 2019

This study develops 3D-printed-garment collections for a fashion show presentation. A design concept using traditional patterns that consisted of garments regarding the limitation of the printing technology was investigated in order to develop the collection. The structures of the connecting joints of the textile parts which could be easily and sturdily interconnected were invented. Wearability as garments that could be naturally worn on the human body were sought. As a result, four 3D-printed-garments were developed. The 1st garment composed of objects based on a 'Yeon-Dang-Cho'-pattern was constructed as a geometric robe style using a FDM 3D printer and transparent TPU filaments. The 2nd and 3rd 3D-printed-garments composed of an object based on a 'Boe-Sang-Hwa'-pattern was constructed as a distorted one-piece exaggerating the silhouettes of shoulders and waist parts as well as a straight asymmetric tunic style that used the same printer and material as the 1st garment. The last garment composed of an object based on a 'Boe-Sang-Hwa'-pattern printed using a SLA 3D printer and flexible-liquid-resin was constructed attaching the objects on the fabric material by the hot-press machine. The four developed garments were presented in the opening fashion show of 'the 6th International 3D-printing Korea Expo'. This study provides a basic case for related studies to adapt 3D-printing technology in textile pattern development of garment construction.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.6
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• pp.1109-1117
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• 2017

Recently, 3D printer technology has been attracting attention in various industrial fields, and research papers are being conducted to utilize 3D printers in the construction industry. Actual structures such as bridges and buildings are being printed to 3D printers, and various applications such as mock-up structures using 3D printers are being proposed. In order to utilize 3D printer technology in the construction field, a 3D model is required, and the 3D BIM data produced at the design stage can be printed by a 3D printers, saving the cost and time of 3D model generation. However, 3D BIM data often does not satisfy the conditions for 3D printer output, causing many errors on output. In this paper, authors propose a problem analysis for 3D BIM model output to 3D printer and a method for reducing errors in 3D printing process of 3D BIM model. In addition, this paper presents a practical application of 3D model output from 3D printer.

• The Journal of Sustainable Design and Educational Environment Research
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• v.19 no.4
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• pp.78-87
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• 2020

This study proposed the basic data that contributes to inducing an effective construction plan through the application of the 4th industrial technology to construct a school building that can guarantee the five goals of construction management: cost, process, quality, safety, and environmental management. To this end, 3D printing, drones, robot automation, and augmented reality technologies that are highly usable in construction sites were identified for construction workers. As part of this, related literature and research data were investigated. The selected 4th industrial technology was investigated and analyzed on how it was used for cost, process, quality, safety, and environmental management in a detailed school construction process. As a result of the analysis, significant results were found for the application plan of the 4th industrial technology in school construction for cost, process, quality, safety, and environmental management.

• Korean Journal of Construction Engineering and Management
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• v.23 no.6
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• pp.119-124
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• 2022

Recently a method of constructing architectural products using additive manufacturing technology has been proposed. The additive manufacturing technology automates the construction process and it can secure the safety of workers. In addition, due to the high implementation efficiency of atypical shapes, the applicability to the manufacturing process of buildings and infrastructure is drawing attention. Additive manufacturing technology has the ability of satisfying computer-based construction automation, resource management and construction period prediction which is required in the modern construction industry. However, the industrial application is still limited by insufficient data, standards, regulations, and operating methods. In this study, in order to analyze the applicability of architectural additive manufacturing technology, we manufacture each architectural product with two additive manufacturing systems. In addition, we apply an application of each building product into an appropriate manufacturing system through the AM production decision model. And identify problems in the manufacturing process through empirical experiments. As a result, we propose an extended additive production decision model to improve the quality of building products.

• Progress in Medical Physics
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• v.28 no.1
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• pp.33-38
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• 2017

Creating individualized build-up material for superficial photon beam radiation therapy at irregular surface is complex with rice or commonly used flat shape bolus. In this study, we implemented a workflow using 3D printed patient specific bolus and describe our clinical experience. To provide better fitted build-up to irregular surface, the 3D printing technique was used. The PolyLactic Acid (PLA) which processed with nontoxic plant component was used for 3D printer filament material for clinical usage. The 3D printed bolus was designed using virtual bolus structure delineated on patient CT images. Dose distributions were generated from treatment plan for bolus assigned uniform relative electron density and bolus using relative electron density from CT image and compared to evaluate the inhomogeneity effect of bolus material. Pretreatment QA is performed to verify the relative electron density applied to bolus structure by gamma analysis. As an in-vivo dosimetry, Optically Stimulated Luminescent Dosimeters (OSLD) are used to measure the skin dose. The plan comparison result shows that discrepancies between the virtual bolus plan and printed bolus plan are negligible. (0.3% maximum dose difference and 0.2% mean dose difference). The dose distribution is evaluated with gamma method (2%, 2 mm) at the center of GTV and the passing rate was 99.6%. The OSLD measurement shows 0.3% to 2.1% higher than expected dose at patient treatment lesion. In this study, we treated Mycosis fungoides patient with patient specific bolus using 3D printing technique. The accuracy of treatment plan was verified by pretreatment QA and in-vivo dosimetry. The QA results and 4 month follow up result shows the radiation treatment using 3D printing bolus is feasible to treat irregular patient skin.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.632-637
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• 2021

In order to develop future construction technology, research is actively being conducted on concrete construction technology using 3D printing, which is currently in the spotlight as a future industry in domestic and foreign construction industries and academia. However, 3D printing technology is currently being developed and does not meet the requirements for proper construction technology and the properties of concrete materials, and it is difficult to apply in the actual field. Research is also needed for the durability management and maintenance of constructed structures. This work compares the compressive and flexural strength to that produced in conventional molds by dividing the 3D printed concrete output by the laminated X, Y, and Z axes. The compressive strength of a test specimen in the II Z-axis test direction was 8-10% higher than that of the other test directions (I and III Y axes and X axis). The strength was 4% lower than that of a molded test specimen. As of 28th of the age, the bending strength of the test specimen in the Z-axis direction was 5 to 7% higher than that of the I and III Y, and X-axis test directions, and the strength was 2% lower than that of the molded test specimen.

• Magazine of RCR
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• v.18 no.4
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• pp.69-73
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• 2023