• Journal of Institute of Convergence Technology
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• v.1 no.1
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• pp.34-40
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• 2011

In this paper, a hybrid design tool combining one-dimensional(1D) lumped model and three-dimensional computational fluid dynamics(CFD) approach has been developed in order to evaluate the performance of inkjet print head and droplet control process are studied to reduce the deviations between nozzles which affect the size of the printed line for the industrial application of direct writing on printed circuit boards(PCB). 1D lumped model analysis shows that it is useful tool for evaluating performance of an inkjet head by varying the design parameters. The differences in ejected volume and droplet velocity between analytical and experimental result are within 12%. Time sequence of droplet generation is verified by the comparison between 3D analysis result and photographic images acquired by stroboscopic technique. In addition, by applying DPN process, velocity and volume uniformity between nozzles is dramatically improved that the tolerance achieved by the piezoelectric inkjet printhead across the 64 nozzles is 5 to 8%. A printed line pattern is successfully obtained using the fabricated inkjet print head and droplet calibration system.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.209-210
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• 2022

This research reviewed the status of binder removal depending on the heating temperature and duration by using the 3D sand mold as an electric heating method. In the case of the electric heating method, it was confirmed that a heating temperature of at least 800℃ or higher was required to remove the binder of the 3D sand mold, and the heating duration was confirmed to be about 10 minutes. Afterwards, it is considered necessary to further evaluate the additional binder removal method and the utilization of recycling silica in consideration of economic feasibility and productivity.

• Proceedings of the Korea Information Processing Society Conference
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• 2017.04a
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• pp.963-965
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• 2017

최근 3D 프린터에 대한 관심이 커지고 있다. 3D 프린팅을 위해서 전용 소프트웨어를 이용하여 설계 파일을 생성하고 출력하지만, 각 3D 프린트마다 지원하는 파일 형식이 다르고, 특정 데이터 파일 형식을 변환할 때에는 별도의 프로그램이 필요하기 때문에 많은 시간과 노력이 필요하다. 본 논문에서는 이러한 일련의 복잡한 과정을 개선하기 위해 입력 파일을 각 3D 프린터가 지원하는 파일 형태로 손쉽게 변환하여 출력할 수 있는 모델링 기법을 제안한다.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.11
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• pp.96-102
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• 2019

Reverse engineering involves duplicating a physical part by measuring and analyzing its physical dimensions, features, and material properties. By combining reverse engineering with three-dimensional (3D) printing, engineers can simply fabricate and evaluate functional prototypes. This design methodology has been attracting increasing interest with the advent of the Fourth Industrial Revolution. In the present study, we apply reverse engineering and 3D printing technologies to evaluate a fabricated automotive inner ring prototype. Through 3D printing, inner rings of various densities were prepared. Their physical dimensions were measured with a 3D scanning system. Of our interest was the effect of inner ring density on the physical dimensions of the fabricated prototype. We compared the design dimensions and physical dimensions of the fabricated prototypes. The results revealed that even the 20% density of inner ring was effective for 3D printing in terms of satisfying the design requirements.

• Journal of Welding and Joining
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• v.32 no.4
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• pp.20-25
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• 2014

Laser heat source was applied on 3D poly urethane model built by 3D printer and cellulous acetate for joining. A diode laser with 808nm wavelength was transmitted through the 3D model and applied on the boundary of ABS/Acetate and 3D poly urethane model. Based on the experimental result, the ABS and 3D built poly-urethane polymers was successfully joined, but the mechanical strength was not enough at the joining boundaries in the range of 6watt to 8watt of laser heat source. However, biodegradable acetate was successfully joined without damaging the 3D built model and mechanical strength was properly achieved. The optimum laser power was found between 5watt and 8watt with scanning speed of 500mm/min, 700mm/min and 1,000mm/min. Based on the SEM analysis the filling mechanism was that the applied pressure on 3D built model squeezed the fluidic thermoplastics, ABS and acetate, into the structure of 3D model. Therefore soundness of joining was strongly depending on the viscosity of thermoplastics in polymers. The developed laser process is expected to increase productivity and minimize the cost for the final products.

• Korean Journal of Optics and Photonics
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• v.17 no.4
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• pp.317-322
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• 2006

A polymeric arrayed waveguide grating (AWG) has been proposed and demonstrated by exploiting the nanoimprint method. A PDMS(polydimethylsiloxane) stamp with device patterns engraved was developed out of a master mold made of quartz glass. The device was fabricated by transferring the pattern in the PDMS stamp to a spin-coated polymer film without using any etching process. The device had 8 output channels, while the center wavelengths of each output channel were positioned from 1543.7 nm to 1548.3 nm with the spacing of 0.8 nm. The achieved average channel crosstalk and the 3-dB bandwidth were about 10 dB and 0.8 nm respectively.

• Journal of Digital Convergence
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• v.12 no.9
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• pp.335-341
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• 2014

Due to the expiration of the 3D printer's patent, the articles covering the market activation and bright prospects for the future industry are being released. What are the requirements for the 3D printer to become popular like a general printer? To get the answer, on-line survey was performed for the activation of 3D printer. As a result, tit is observed that he public prefers creative printer and figure, and prefers to use through pay or free download rather than designing digital blueprint, which is output data. For the activation and popularization of 3D printer, figure is familiar to the public who are frequently exposed to image media contents, and it also has motivation factor to use and purchase 3D printer. For distribution of digital blueprint of figure content, the preparation of related law and regulation and activation of online market would be of help for activation of 3D printer.

• KIPS Transactions on Software and Data Engineering
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• v.12 no.5
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• pp.229-236
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• 2023

Since 3D printed medical implant parts usually have surface defects, it is necessary to inspect the surface after manufacturing. In order to automate the surface inspection, it is effective to 3D scan the implant and reconstruct it as a scan model such as a point cloud. When constructing a scan model, the characteristics of the shape and material of the implant must be considered because it has characteristics different from those of general 3D printed parts. In this paper, we present a method to reconstruct the 3D scan model of a 3D printed metal bone-plate that is one kind of medical implant parts. Multiple partial scan data are produced by multi-view 3D scan, and then, we reconstruct a scan model by alignment and merging of partial data. We also present the process of the scan model reconstruction through experiments.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.4
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• pp.43-48
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• 2015

A focal length-correcting lens called the F-theta lens is required to compensate for the different focus on spot size due to the deflected incident laser beam. The F-theta lens was designed by the ray tracing method and fabricated by a 3D printer with polymer-based material. The designed F-theta lens is able to compensate for the focus on spot size by an incidence angle of 0 to 2 degrees. Based on the analysis of the simulation, there was almost no aberration in the $0^{\circ}C$ incidence angle, and the maximum of $50{\mu}m$ of aberration was observed at the incidence angle of $2^{\circ}$. Diffraction-encircled energy was analyzed to characterize the designed optics, and an image simulation was performed to confirm the actual image resolution.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.4
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• pp.49-54
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• 2015

The fabrication of a focal length-correcting lens called the F-theta lens was performed by a 3D printer. The fabricated lenses were characterized by transmittance and reflectance measurements. The optical properties of the lens, such as scattering or transmittance efficiency, were analyzed with respect to the wavelength (red, green, and blue) and the surface roughness of the lens. There was almost no shape aberration on the focus location of 0 degrees, but elliptical focus shapes were found at 1 and 2 degrees of the laser incidence angle. The developed process is expected to be used for the quick fabrication of lenses with low costs and quick turn-out. By improving the surface roughness during postprocessing, the optical properties are expected to be comparable to commercial lens quality.