• Journal of radiological science and technology
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• v.44 no.6
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• pp.615-621
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• 2021

In the medical field, radiation provides information for the diagnosis and treatment of diseases. As the use of radiation increases and the risk of exposure increases, interest in radiation protection is also rapidly increasing. Lead shielding material is mainly used, which has a risk of lead poisoning and absorption into the body. Tungsten mixed filament shielding sheets were fabricated with a size of 70 × 70 mm and a thickness of 1, 2, and 4 mm by using a 3D printer. In the general shooting experiment, the thickness of the shielding sheet is 1 ~ 5mm, the tube voltage is 60, 80, 100, 120 kVp and the tube current is 20, 40 mAs. In general photography, Tungsten showed better shielding rate compared to Brass, Copper, and Lead protective tools under all irradiation conditions, and in particular, Tungsten 5 mm showed 100% shielding rate. The 3D-printed tungsten mixed filament shielding is expected to be used as a new shield that can replace the existing lead protection tools as it shows a better shielding rate than the existing lead protection tools in Radiography.

• Journal of the Korean Society of Radiology
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• v.14 no.5
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• pp.627-634
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• 2020

Instead of lead, we intend to develop shielding materials for morphological implementation by mixing barium sulfate, an eco-friendly substance, and PLA filament, a 3D printer material. The environmental substance, barium sulfate powder and PLA filament, a 3D printer material, were used, and the shielding was made with a 3D printer after being fused into an extruder to mix the powder powder of barium sulfate with PLA. To check the mixing ratio of barium sulfate powder and PLA filament, the mixing input was analyzed, and the absorption dose by thickness according to barium sulfate content was obtained to check the shielding function of the mixed shielding. In the evaluation of the mixture of sulfate barium powder particles and PLA filaments, it was mixed in the most appropriate proportion when the content was 30% in the apparent and electron microscopic observation photographs. In the absorption dose results by thickness according to barium sulfate content, the difference between the content of 0% and the content of each % was greatest at 0.5 cm in thickness and the lowest dose value at 3 cm in thickness when the barium content was 30%. In addition, as the barium content began to increase at 30%, the absorbed dose value increased again. Instead of conventional lead, barium sulfate, an eco-friendly substance, could be mixed with PLA, a filament material, to create morphological shielding. Based on this study, it is expected that the mixing ratio of barium to the mixture is the most appropriate 30%, and will be used as the basis for the implementation of morphological shielding using 3D printers in the diagnosis and treatment section.

• Journal of the Korean Wood Science and Technology
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• v.46 no.1
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• pp.107-113
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• 2018

In this study, the 3D printer filaments were manufactured by using the representative eco-friendly material, bio-composite. Bio-composites were made by incorporating biodegradable polymer of poly lactic acid (PLA) as the matrix and bamboo flour as the filler. The bamboos which were used in this experiment are Phyllostachys bambusoides, Phyllostachys nigra var. henonis, and Phyllostachys pubescen grown in Damyang district in Korea, and the mixture ratio between bamboo flour and PLA were set 10/90, 20/80, 30/70 by weight standard. Also, tensile strength of bamboo/PLA bio-composites manufactured with three kinds of bamboo were estimated and compared. In this result, the highest estimated bio-composites was Phyllostachys bambusoides flour/PLA which mixture ratio was 10/90, that is, it was the most suitable bamboo/PLA bio-composites for manufacturing 3D printer filament.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.6
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• pp.141-152
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• 2015

Most of agricultural structures are consisted of complex components and exposed to various boundary conditions. There have been no ways to express those structures exactly for model experiment. As an alternative, 3D printer can produce any type of solid model. However, there are limited informations related to structural experiments using 3D printer. The object of this study gives the basic informations to structural engineers who try to use 3D printer for model experiment. When PLA was used as a supplier for 3D printer, the outcomes showed less heat deformation to compare with ABS. To test the material properties, two kinds of experiments (three-point flexibility test and compression test) were executed using universal testing machine. In three-point flexibility test, plastic hinge and its deformation were developed as observed in material such as steel. The behavior was in a linear elastic state, and elastic bending modulus and yield force were evaluated. In the compression test using unbraced columns with hinge-hinge boundary condition, the constant yield forces were observed regardless of different lengths in all columns with same section size, whereas the compressive elastic modulus was increased as the length of column was increased. The suggested results can be used for model experiments of various agricultural structures consisted of single material.

• Journal of the Korean Society of Radiology
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• v.12 no.7
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• pp.879-886
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• 2018

A 3-dimensional (D) printer is a device capable of outputting a three-dimensional solid object based on data modeled in a computer. These features are utilized in the bone model X - ray phantom production etc using CT data by fusing with the radiation science field. A bone model phantom was made using data obtained by CT scan of an existing Pelvis phantom, using PLA, Wood, XT-CF20, Glow fill, Steel filaments which are materials of Fused Filament Fabrication (FFF) 3D printer.Measure Hounsfield Unit (HU) with images obtained by CT scan of the existing Pelvis phantom and five material phantoms made with 3D printer under the same conditions,SI and SNR were measured using a diagnostic X-ray generator, and each phantom was compared and analyzed.As a result, the X - ray phantom in the X - ray examination condition of the limb was found to be most suitable for the glow fill filament.The characteristics of the filament can be known to the base of this research and the practicality of X - ray phantom fabrication was confirmed.

• Journal of radiological science and technology
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• v.43 no.6
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• pp.453-460
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• 2020

The price of the Brain phantom (Hoffman 3D brain phantom) used in nuclear medicine is quite expensive, it is difficult to be purchased by a medical institution or an educational institution. Therefore, the purpose of present research is to produce a low-price 3D brain phantom and evaluate its usefulness by using a 3D printer capable of producing 3D structures. The New 3D brain phantom consisted of 36 slices 0.7 mm thick and 58 slices 1.5 mm thick. A 0.7 mm thick slice was placed between 1. 5 mm thick slices to produce a composite slice. ROI was set at the gray matter and white matter scanned with CT to measure and compare the HU, in order to verify the similarity between PLA which was used as the material for the New 3D brain phantom and acrylic which was used as the material for Hoffman 3D brain phantom. As a result of measuring the volume of each Phantom, the error rate was 3.2% and there was no difference in the signal intensity in five areas. However, there was a significant difference in the average values of HU which was measured at the gray and white matter to verify the similarity between PLA and acrylic. By reproducing the previous Hoffman 3D brain phantom with a 100 times less cost, I hope this research could contribute to be used as the fundamental data in the areas of 3D printer, nuclear medicine and molecular imaging and to increasing the distribution rate of 3D brain phantom.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.1
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• pp.33-39
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• 2022

As 3D printer-related patents expire and major technologies are disclosed, the price of 3D printers is dropping, creating an environment where you can easily find the product you want. In particular, the cheapest FDM (Fused Deposition Modeling) 3D printer is being used in various fields. The FDM method can be manufactured without collapsing of the shape only by attaching a support under certain conditions when outputting the shape. When printing a shape without a support, the irregular surface that occurs at a certain angle is a defect in the product, but it is considered that it can be used as another fun factor in terms of arts and crafts. In this paper, to obtain such an irregular surface, factors that can affect the output were controlled and only the output angle was tested as a displacement factor. As a result of the experiment, it was possible to obtain an irregular surface without the filament flowing down when printing at an angle of 62° to 70° from the vertical. Also, artificially irregular surfaces were applied to craft products.

• Journal of the Korean Society of Radiology
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• v.13 no.4
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• pp.565-572
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• 2019

In this study, shielding analysis of material and thickness of 3D printer filaments was performed for the manufacture of custom shielding by radiation workers during outdoor radiographic test. The shielding was attached to the ICRU Slab Phantom after selecting the voxel source $^{192}Ir$ and $^{75}Se$ through simulation using MCNPX, and the distance between the source and the slab Phantom was set at 100 cm. The 12 shielding materials were divided into 5 mm units up to 200 mm from the absence of shielding materials to evaluate the energy absorbed per unit mass of each shielding material. The results showed that the shielding effect was high in the order of ABS + Tungsten, ABS + Bismuth, PLA + Copper, PLA + Iron from all sources of radiographic test. However, compared to lead, the shielding effect was somewhat lower. Based on this study in the future, further study of the atomic number and the high density filament material is necessary.

• Journal of radiological science and technology
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• v.46 no.6
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• pp.519-526
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• 2023

This study was intended to evaluate the shielding rate of radiation shields manufactured using 3D printers that have recently been used in various fields by comparing them with existing shields made of lead, and to find out their applicability through experiments. A 3D printer shield made of tungsten filament 1 mm, 2 mm, 4 mm shield, RNS-TX (nanotungsten) 1.1 mm, lead 0.2 mmPb, and 1mmPb were exposed to ^99mTc, ¹⁸F, and ²⁰¹TI for 15, 30, 45 minutes, and 60 minutes after measuring cumulative dose three times. Based on this, the shielding rate of each shield was calculated based on the dose in the absence of the shield. In addition, ^99mTc, ¹⁸F, and ²⁰¹TI were located 100 cm away from the phantom in which the OSLD nano Dot device was inserted, and if there was no shield for 60 minutes, the dose of thyroid was measured using 1.0 mm of lead shield, 1.1 mm of RNS-TX shield, and 2 mm of tungsten shield made by 3D printer. The use of shields during radiation shielding emitted from open radiation sources all resulted in a reduction in dose. The radiation dose emitted from the radionuclides under the experiment was all reduced when the shield was used. This study has been confirmed that tungsten is a material that can replace lead due to its excellent performance and efficiency as shield, and that it even shows the possibility of manufacturing a customized shield using 3D printer.

• Journal of Drive and Control
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• v.17 no.4
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• pp.97-102
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• 2020

This paper presents the basic research for the design and fabrication of a 3D-printed load cell made of NCPC (nano-carbon piezo-resistive composite). We designed a structure that can resonate at a low frequency range of about 5-6 Hz with ANSYS using sensitivity analysis and a response surface method. The design was verified by fabricating the device with a low-quality commercial 3D printer and ABS filament. We conducted a feasibility test for a commercial sensor using 1000 cyclic load tests at 0.3 Hz in a material testing system. A manufacturing process for the 3D printer filament based on the NCPC was also developed using the nano-composite process.