• Journal of the Korean Society for Precision Engineering
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• v.31 no.12
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• pp.1085-1091
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• 2014

Recently, 3D printing has received increasing attention due to its boundless potentials. Because 3D printing starts from 3D geometry information, computer-aided design (CAD) is an essential technology to build 3D geometry data. These days, education of 3D CAD for engineering students has been changed from the theoretical lecture to practical design training using commercial CAD software. As a result, open-ended design projects have replaced the traditional theoretical examinations to evaluate students' outcomes. However, such design projects are not enough to evaluate students' outcomes because their results are expressed in two-dimensional ways. In this paper, applications of 3D printing in engineering design education are discussed by describing the procedure and outcomes of design projects. It was found that the use of 3D printing could improve students' outcomes by fabricating real physical models out of their designs.

• Journal of Energy Engineering
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• v.29 no.3
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• pp.50-56
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• 2020

Currently, 3D printing technology is a new revolutionary additive manufacturing process that can be used for making three dimensional solid objects from digital films. In 2019, this 3D printing technology spreading vigorously in production parts (57%), bridge production (39%), tooling, fixtures, jigs (37%), repair, and maintenance (38%). The applications of 3D printing are expanding to the defense, aerospace, medical field, and automobile industry. The raw materials are playing a key role in 3D printing. Various additive materials such as plastics, polymers, resins, steel, and metals are used for 3D printing to create a variety of designs. The main advantage of the green cement for 3D printing is to enhance the mechanical properties, and durability to meet the high-quality material using in construction. There are several advantages with 3D printing is a limited waste generation, eco-friendly process, economy, 20 times faster, and less time-consuming. This research article reveals that the role of green cement as an additive material for 3D printing.

• Journal of dental hygiene science
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• v.15 no.2
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• pp.196-201
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• 2015

The purpose of this study was to evaluate marginal gap of 3 unit fixed dental prostheses (FDPs) fabricated by 3-dimensional (3D) printing technology and to compare marginal gap of its by a conventional method (lost wax technique and casting method). Ten study models were manufactured. Three unit FDPs were fabricated by 3D printing technique (3D group) and conventional methods (CV group). Marginal gaps were measured by silicone replica technique and digital microscope (${\times}160$). Mann-Whitney test was executed (${\alpha}=0.05$). The mean${\pm}$standard deviation of marginal gap for premolars and molars were $112.5{\pm}8.6{\mu}m$ and $110.2{\pm}7.0{\mu}m$ in the 3D group and $83.2{\pm}4.4{\mu}m$ and $82.2{\pm}4.6{\mu}m$ in the CV group. There were statistically significant differences (p<0.05). As results, clinical application further improvement of 3D printing technique may be required.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1390-1393
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• 2004

In the present industry, three-dimensional colored shape has required for realistic prototype in rapid manufacturing. Z-corporation developed 3D printer which can color three-dimensional prototype but this process can't be adopted to other rapid prototype products and spend much time and cost coloring 3D shape. In this study a new coloring process on three-dimensional surface is proposed for realistic prototype. Three-dimensional surface coloring apparatus is composed of HP ink jet head and X-Y plotter. Distance and angle between ink jet nozzle and 3D surface are set as process parameter. Based on the experiment of process parameters, it is shown that distance and angle affected on printed image on 3D surface. Circle and line shape are chosen as standard image shape because the shape has widely used as standard in 2D printing. Consequently, the distorted image on 3D surface is corrected by transformed input image data.

• Macromolecular Research
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• v.17 no.3
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• pp.197-202
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• 2009

Solution-based, direct-write patterning by an automated, computer-controlled, inkjet technique is of particular interest in a wide variety of industrial fields. We report the construction of three-dimensional (3D), micro-patterned structures by polymer inkjet printing. A piezoelectric, drop-on-demand (DOD) inkjet printing system and a common polymer, PVA (poly(vinyl alcohol)), were explored for 3D construction. After a systematic preliminary study with different solvent systems, a mixture of water and DMSO was chosen as an appropriate solvent for PVA inks. The use of water as a single solvent resulted in frequent PVA clogging when the nozzles were undisturbed. Among the tested polymer ink compositions, the PVA inks in a water/DMSO mixture (4/1 v/v) with concentrations of 3 to 5 g/dL proved to be appropriate for piezoelectric DOD inkjet printing because they were well within the proper viscosity and surface tension range. When a dot was printed, the so-called 'coffee-ring effect' was significant, but its appearance was not prominent in line printing. The optimal polymer inkjet printing process was repeated slice after slice up to 200 times, which produced a well-defined, 3 D micro-patterned surface. The overall results implied that piezoelectric DOD polymer inkjet printing could be a powerful, solid-freeform, fabrication technology to create a controlled 3D architecture.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.6
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• pp.142-148
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• 2015

3D printing technology is a promising technique for fabricating complex 3D architectures based on the CAD/CAM system, and it has been extensively investigated to manufacture structures in the fields of mechanical engineering, space technology, automobiles, and biomedical and electrical applications. Recent advances in the 3D printing of soft structures have received attention for the application of the construction of flexible sensors of soft robotics or the recreation of tissue/organ-specific microenvironments. In this review paper, we would like to focus on delivering state-of-the-art fabrication of soft structures with 3D printing technology and its various applications.

• Journal of Technologic Dentistry
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• v.42 no.4
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• pp.355-361
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• 2020

Purpose: In this study, we added two kinds of photoinitiators (CQ and TPO) to prepare two kinds of denture base resins (Bis-GMA series and UDMA series) for three-dimensional (3D) printing to compare and analyze their mechanical and biological properties and to find the optimal composition. Methods: Control specimens were made using the mold made of polyvinyl siloxane of the same size. Light curing was performed twice for 20 seconds on both the upper and lower surfaces with LED (light emitting diode) light-curing unit (n=10). Experimental 3D printing dental resins were prepared, to which two photoinitiators were added. Digital light processing type 3D printer (EMBER, Autodesk, CA, USA) was used for 3D printing. The specimen size was 64 mm×10 mm×3.3 mm according to ISO 20795-1. The final specimens were tested for flexural strength and flexural modulus, and MTT test was performed. Furthermore, one-way analysis of variance was performed, and the post-test was analyzed by Duncan's test at α=0.05. Results: The flexural strength of both Bis-GMA+CQ (97.12±6.47 MPa) and UDMA+TPO (97.40±3.75 MPa) was significantly higher (p<0.05) in the experimental group. The flexural modulus in the experimental group of UDMA+TPO (2.56±0.06 GPa) was the highest (p<0.05). MTT test revealed that all the experimental groups showed more than 70% cell activity. Conclusion: The composition of UDMA+TPO showed excellent results in flexural strength, flexural modulus, and biocompatibility.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.497-499
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• 2005

A portable terminal assistant market grows rapidly every year and it requires many change in research on display devices. Among many newly developing methods, OLED(Organic Light Emitting Diode) is considered an advanced flat display device because its excellent characteristics, including high speed response, full color performance, low power consumption and flux of panel. However changes in the market of display shows that the market will require 3-dimensional images, but it is hard for existing 2-dimensional displays to make 3-dimensional images. Therefore we will try to find various methods such as holograms. In this paper, we will show existing flat displays can make 3-dimensional images by applying Lenticular Screen printing techniques on the organic semiconductor display device.

• The Journal of the Korea Contents Association
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• v.15 no.1
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• pp.308-315
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• 2015

The purpose of this study, using 3D printer, was tried to fabricate the short arm cast of mesh types that can be hygienic and adequate ventilation with a good radiography. We used the multi channel computed tomography (MDCT) with three dimension printer device of the fused deposition modeling (FDM) techniques. The material is used a degradable plastic (poly lactic acid, PLA). Three-dimensional images of the short arm were obtained in the MDCT and then make the three-dimensional volume rendering. Three dimension volume rendering of the short arm is implemented as a tomography obtained in MDCT. Virtual mesh type cast model was output as three-dimensional images is designed based on the three-dimensional images of the short arm. As a results, the cast output by 3D printers were able to obtain excellent radiograph images than the conventional cast, and then it can decreased itching with unsanitary, and can break down easily to the cast. In conclusion, the proposed virtual mesh type cast output by 3D printers could be used as a basis for future three-dimensional printing cast productions and offered help to patients in the real life.

• Journal of Biomedical Engineering Research
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• v.39 no.5
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• pp.188-207
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• 2018

Recently, three-dimensional (3D) printing of biological tissues and organ has become an attractive interdisciplinary research topic that combines a broad range of fields including engineering, biomaterials science, cell biology, physics, and medicine. The 3D bioprinting can be used to produce complex tissue engineering scaffolds based on computer designs obtained from patient-specific anatomical data. It is a powerful tool for building structures by printing cells together with matrix materials and biochemical factors in spatially predefined positions within confined 3D structures. In the field of the 3D bioprinting, three major categories of the 3D bioprinting include the stereolithography-based, inkjet-based, and dispensing-based bioprinting. Some of them have made significant process. Each technique has its own advantages and limitations. Compared with non-biological printing, the 3D bioprinting should consider additional complexities: biocompatibility, degradability of printing materials, cell types, cell growth, cell viability, and cell proliferation factors. Numerous 3D bioprinting technologies have been proposed, and some of them have been making great progress in printing several tissues including multilayered skin, cartilaginous structures, bone, vasculature even heart and liver. This review summarizes basic principles and key aspects of some frequently utilized printing technologies, and introduces current challenges, and prospects in the 3D bioprinting.