• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1394-1399
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• 2007

Recently, Study of 3D freeform fabrication method was working in the various applications. For example, in the powder base, it's laminated using a binding method or laser sintering method. However, these methods are not suitable in the office environments because it dust with powder that is bad for health. In this paper, we introduce a method of 3D freeform fabrication using a curing of photo-polymer resin and construct a system has multi printing head. A photo-polymer curing method has simply fabrication process and high strength of manufacturing part. However, this method has a problem on the multi print-head system. Because multi-printing system has a other printing method compare with a single printing system. Therefore, we experiment a single head 3D printing and proposed a 3D printing method using a multi-piezo head.

• The Journal of Advanced Prosthodontics
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• 제12권5호
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• pp.322-328
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• 2020

PURPOSE. This study evaluated the shear bond strength between 3D printed provisional resin and conventional provisional resin depending on type of conventional provisional resin and different surface treatments of 3D printed resin. MATERIALS AND METHODS. Ninety-six disc-shaped specimens (Ø14 mm × 20 mm thickness) were printed with resin for 3D printing (Nextdent C&B, Vertex-Dental B. V., Soesterberg, Netherlands). After post-processing, the specimens were randomly divided into 8 groups (n=12) according to two types of conventional repair resin (methylmethacrylate and bis-acryl composite) and four different surface treatments: no additional treatment, air abrasion, soaking in methylmethacrylate (MMA) monomer, and soaking in MMA monomer after air abrasion. After surface treatment, each repair resin was bonded in cylindrical shape using a silicone mold. Specimens were stored in 37℃ distilled water for 24 hours. The shear bond strength was measured using a universal testing machine at a crosshead speed of 0.5 mm/min. Failure modes were analyzed by scanning electron microscope. Statistical analysis was done using one-way ANOVA test and Kruskal-Wallis test (α=.05). RESULTS. The group repaired with bis-acryl composite without additional surface treatment showed the highest mean shear bond strength. It was significantly higher than all four groups repaired with methylmethacrylate (P<.05). Additional surface treatments, neither mechanical nor chemical, increased the shear bond strength within methylmethacrylate groups and bis-acryl composite groups (P>.05). Failure mode analysis showed that cohesive failure was most frequent in both methylmethacrylate and bis-acryl composite groups. CONCLUSION. Our results suggest that when repairing 3D printed provisional restoration with conventional provisional resin, repair with bis-acryl composite without additional surface treatment is recommended.

• 대한방사선기술학회지:방사선기술과학
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• 제39권3호
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• pp.337-344
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• 2016

본 연구에서는 3차원(3-dimensional, 3D) 프린팅 기술로 출력된 팬톰에 대한 X선 투과성을 평가하고자 하였다. 3D 프린팅 방식은 용융적층조형(fused deposition modeling, FDM) 방식을 이용했으며 소재는 아크릴로나이트릴 뷰타다이엔 스타이렌(acrylonitrile butadiene styrene, ABS)을 사용하였다. 팬톰은 원통 모양으로 설계하였으며 전산화단층영상장비(computed tomography, CT)에서 획득한 단면영상으로 균일도를 측정하였다. X선 투과성 평가는 3D 출력된 팬톰 내부에 이온챔버를 삽입하여 실시하였다. 그 결과, 평균 균일도가 2.70 HU이었으며 기존 폴리메틸 메타크릴레이트(poly methyl methacrylate, PMMA) CT 팬톰과 3D 프린터로 출력된 팬톰에서 측정된 X선 투과성의 상관관계는 0.976로 높은 상관관계가 있는 것으로 나타났다. 향후 3D 프린팅 기술을 이용한 방사선정도관리 팬톰 제작에 기초자료로 활용할 수 있으리라 기대한다.

• 한국산학기술학회논문지
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• 제16권9호
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• pp.6019-6026
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• 2015

본 연구에서는 소량생산 및 개인 맞춤형 제작으로 매우 유용한 3D 프린팅 기술을 이용하여 자가 맞춤형 부목을 제작하고자 하였다. 방법으로는 3D 프린터를 이용하여 용융적층조형방식(fused deposition modeling)으로 부목을 제작하였으며, 재료는 열가소성 플라스틱 계열인 ABS(acrylonitrile butadiene styrene) 수지를 이용하였다. 부목의 모델링은 실제 인체의 손 부위 3차원 전산화단층영상을 이용하였으며 통풍이 가능하도록 설계하였다. 그 결과 실제 인체 손 모양과 일치하는 자기 맞춤형 부목이 성공적으로 출력되었다. 또한 기존 부목보다도 우수한 방사선영상을 획득할 수 있었다. 결론적으로 본 연구에서 제시한 3D 프린팅 사례는 ABS 수지를 이용한 용융적층조형방식의 유사한 구조물을 출력할 때 기초자료로 사용할 것으로 판단된다.

• Design & Manufacturing
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• 제12권3호
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• pp.19-24
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• 2018

Fused deposition Modeling (FDM) is one of the most widely used for the prototype of parts at ease. The FDM 3D printing method is a lamination manufacturing method that the resin is melted at a high temperature and piled up one by one. Another term is also referred to as FFF (Fused Filament Fabrication). 3D printing technology is mainly used only in the area of prototype production, not in production of commercial products. Therefore, if FDM 3D printer is applied to the product process of commercial products when considered, the strength and dimensional accuracy of the manufactured product is expected to be important. In this study, the mechanical properties of parts made by 3D printing with FDM method were investigated. The aim of this work is to examine how the mechanical properties of the FDM parts, by changing of processing FDM printing direction and the height of stacking layer is affected. The effect of the lamination direction and the height of the stacking layer, which are set as variables in the lamination process, by using the tensile specimen and impact specimen after the FDM manufacturing process were investigated and analyzed. The PLA (Poly Lactic Acid) was used as the filament materials for the 3D printing.

• 세라미스트
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• 제23권1호
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• pp.4-15
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• 2020

The recent advances and popularity of 3D printing technology have centered around building polymerbased 'plastic' materials, due to their low cost, simple and efficient processing, and mechanical toughness. For this reason, printable polymers are actively recruited to create 'ceramic resins' that allow more facile fabrication of ceramic materials that are difficult to print directly. Herein, a brief history and the current state of ceramic 3D printing technology aided by polymer is summarized. In addition, a new ceramic 3D printing technology using polymer-derived ceramics (PDC) is also introduced.

• Design & Manufacturing
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• 제16권3호
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• pp.58-65
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• 2022

Micro-fluidic chip has been fabricated by lithography process on silicon or glass wafer, casting using PDMS, injection molding of thermoplastics or 3D printing, etc. Among these processes, 3D printing can fabricate micro-fluidic chip directly from the design without master or template for fluidic channel fabricated previously. Due to this direct printing, 3D printing provides very fast and economical method for prototyping micro-fluidic chip comparing to conventional fabrication process such as lithography, PDMS casting or injection molding. Although 3D printing is now used more extensively due to this fast and cheap process done automatically by single printing machine, there are some issues on accuracy or surface characteristics, etc. The accuracy of the shape and size of the micro-channel is limited by the resolution of the printing and printing direction or layering direction in case of SLM type of 3D printing using UV curable resin. In this study, the printing direction and thickness of each printing layer are investigated to see the effect on the size, shape and surface of the micro-channel. A set of micro-channels with different size was designed and arrayed orthogonal. Micro-fluidic chips are 3D printed in different directions to the micro-channel, orthogonal, parallel, or skewed. The shape of the cross-section of the micro-channel and the surface of the micro-channel are photographed using optical microscopy. From a series of experiments, an optimal printing direction and process conditions are investigated for 3D printing of micro-fluidic chip.

• Elastomers and Composites
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• 제51권4호
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• pp.275-279
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• 2016

Additive manufacturing or 3D printing is a new manufacturing process and its application is getting growth. However, the product qualities such as mechanical strength, dimensional accuracy, and surface quality are low compared with conventional manufacturing process such as molding and machining. In this study not only mechanical characteristics of polymer sandwich panel having three dimensional core layer but also mechanical characteristics of core layer itself were analyzed. The shape of three dimensional core layer was pyramidal kagome structure. This core layer was fabricated by two different methods, injection molding with PP resin and material jetting type 3D printing with acrylic photo curable resin. The material for face sheets in the polymer sandwich panel was PP. Maximum load, stiffness, and elongation at break were examined for core layers fabricated by two different methods and also assembled polymer sandwich panels. 3D printed core showed brittle behavior, but the brittleness decreased in polymer sandwich panel containing 3D printed core. The availability of 3D printed article for the three dimensional core layer of polymer sandwich panel was verified.

• 한국산업보건학회지
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• 제28권3호
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• pp.241-256
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• 2018

Objectives: This study aimed to review the characteristics of three-dimensional printing technology focusing on printing types, materials, and health hazards. We discussed the methodologies for exposure assessment on hazardous substances emitted from 3D printing through article reviews. Methods: Previous researches on 3D printing technology and exposure assessment were collected through a literature review of public reports and research articles reported up to July 2018. We mainly focused on introducing the technologies, printing materials, hazardous emissions during 3D printing, and the methodologies for evaluation. Results: 3D printing technologies can be categorized by laminating type. Fused deposition modeling(FDM) is the most widely used, and most studies have conducted exposure assessment using this type. The printing materials involved were diverse, including plastic polymer, metal, resin, and more. In the FDM types, the most commonly used material was polymers, such as acrylonitrile-butadiene-styrene(ABS) and polylactic acids(PLA). These materials are operated under high-temperature conditions, so high levels of ultrafine particles(mainly nanoparticle size) and chemical compounds such as organic compounds, aldehydes, and toxic gases were identified as being emitted during 3D printing. Conclusions: Personal desktop 3D printers are widely used and expected to be constantly distributed in the future. In particular, hazardous emissions, including nano sized particles and various thermal byproducts, can be released under operation at high temperatures, so it is important to identify the health effects by emissions from 3D printing. Furthermore, appropriate control strategies should be also considered for 3D printing technology.

• 한국정밀공학회지
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• 제32권9호
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• pp.781-786
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• 2015

Recently, studies of 3D printing methods have been working in various applications. For example, the powder base method laminates the prints by using a binding or laser sintering method. However, the draw back of this method is that the post process is time consuming and does not allow for parts to be rapidly manufactured. The binding method requires the post process while the time required for the post process is longer than the manufacturing time. This paper proposes a UV curing binding method with an integrated piezo printing head system. The optimization of an arbitrary waveform generation for the control of a UV curable resin droplet was researched, in addition to developed optimized UV curing processes in multi nozzle ink jet heads.