실제 3D 프린팅 작업장에서 발생하는 공기 중 유기화합물, 금속 및 입자특성 평가

김성호,정은교,김세동,권지운 한국산업보건학회 2020 한국산업보건학회지 Vol.30 No.2

Objectives: 3D printing technologies have become widely developed and are increasingly being used for a variety of purposes. Recently, the evaluation of 3D printing operations has been conducted through chamber test studies, and actual workplace studies have yet to be completed. Therefore, the objective of this study was to determine the emission of volatile organic compounds(VOCs), metals, and particles from printing operations at a workplace. This included monitoring conducted at a commercial 3D printing service workplace where the processes involved material extrusion, material jetting, binder jetting, vat photo polymerization, and powder bed fusion. Methods: Area samples were collected with using a Tenax TA tube for VOC emission and MCE filter for metals in the workplace. For particle monitoring, Mini Particle Samplers(MPS) were also placed in the printer, indoor work area, and outdoor area. The objective was to analyze and identify particles’ size, morphology, and chemical composition using transmission electron microscopy with energy dispersive spectroscopy(TEM-EDS) in the workplace. Results: The monitoring revealed that the concentration of VOCs and metals generated during the 3D printing process was low. However, it also revealed that within the 3D printing area, the highest concentration of total volatile organic compounds(TVOC) was 4,164 ppb at the vat photopolymerization 3D printing workplace, and the lowest was 148 ppb at the material extrusion 3D printing workplace. For the metals monitoring, chromium, which, is carcinogenic for humans, was detected in the workplace. As a characteristic of the particles, nano-sized particles were also found during the monitoring, but most of them were agglomerated with large and small particles. Conclusions: Based on the monitoring conducted at the commercial 3D printing operation, the results revealed that the concentration of VOCs and metals in the workplace were within Korea’s occupational exposure limits. However, due to the emission of nano-sized particles during 3D printing operations, it was recommended that the exposure to VOCs and metals in the workplace should be minimized out of concern for workers’ health. It was also shown that the characteristics of particles emitted from 3D printing operations may spread widely within an indoor workplace.

Fabrication of fine metal patterns using an additive material extrusion process with a molten metal

Kim, Yeongjun,Lee, Junhee,Oh, Je Hoon Elsevier 2018 Microelectronic engineering Vol.191 No.-

<P><B>Abstract</B></P> <P>The objective of this work is to establish a volumetric metal 3-dimensional (3D) printing system based on material extrusion method and to fabricate metal patterns by investigating various process variables. Numerical heat transfer simulation was conducted to design the nozzle system with a minimized heat loss at the nozzle tip. Based on the simulation results, a metal 3D printing system with X, Y, and Z stages was constructed. The effects of lead content in molten metals and printing conditions such as stage speed and flow rate were investigated. The line formation like bulged, uniform, and dashed lines was evaluated using an optical microscope, and the variation in line widths of uniform lines was investigated with the process variables. Various types of 2-dimensional (2D) patterns were fabricated with an optimized process variable. A simple 3D structure was obtained to demonstrate the feasibility of the proposed system and procedure.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Design and heat transfer simulation for a metal three-dimensional (3D) printing system </LI> <LI> Establishment and evaluation of the metal 3D printing system </LI> <LI> Line instability and line width of two-dimensional (2D) printed patterns </LI> <LI> 3D printed thin wall from the results of 2D printing </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

3 차원 금속 프린팅 공정의 preprocessor 기능

류수아(Sua Ryu),이성규(Seongkyu Lee),박진옥(Jinok Park),안은주(Eunju An),지해성(Haeseong Jee) (사)한국CDE학회 2013 한국 CAD/CAM 학회 학술발표회 논문집 Vol.2013 No.8

The working principle of the direct 3D metal printing process is the use of a laser to selectively clad metallic powder. A high-powered laser beam is focused on a metal substrate to create a molten weld pool. Metallic powder is then injected into the weld pool by an inert carrier gas. The powder is melted in the pool; as the laser passes by the deposit is quickly cooled, leaving behind a thin line of metal. The major strength of the 3D metal printing process is its ability to deposit a multitude of materials. Since the material deposition relies only on the feeding of a powder or wire, it is relatively simple to use multiple kinds of materials. Currently titanium, nickel, cobalt, steel, and aluminum can be deposited with 3D metal printing process. In fact, recent research has shown that 3D metal printing process is capable of manufacturing binary functionally graded materials as well. The study is to develop a preprocessor functionality generating 2-D/3-D tool paths for the unique process.

A Study on the Status of Metal 3D Printing and Design Methods of Printing Materials

차명희 차세대컨버전스정보서비스학회 2018 차세대컨버전스정보서비스기술논문지 Vol.7 No.2

3D printing technology, which is capable of manufacturing complicated shapes much easier than conventional molding processes, such as casting/ forging, extrusion, injection, welding, and etc., as well as reducing manufacturing time and making various kinds of small quantity products end users want, is rapidly emerging as an innovative technology that can change the existing manufacturing industry paradigm. In particular, metal 3D printing technology has large industrial ripple effects because it can be applied to a wide range of industrial fields from existing main industries such as automobiles, space / aviation, and marine vessels to advanced industries such as defense, bio / medical, and electromagnetic fields, resulting in a growing interest in metal 3D printing in the corresponding industry sectors. However, the research on metal 3D printing technology worldwide is only at a beginning stage. In this study, the present status and problems of the development of the powder materials for metal 3D printing and the design methods of future materials for metal 3D printing shall be discussed.

3D 프린팅용 금속 입자 필라멘트의 물성 및 차폐 능력 평가

박기석(Ki-Seok Park),최우전(Woo-Jeon Choi),김동현(Dong-Hyun Kim) 한국방사선학회 2021 한국방사선학회 논문지 Vol.15 No.5

3D 프린팅 FDM방식의 재료인 필라멘트 중 차폐성능을 지닌 필라멘트는 국내에 판매되지 않고 있으며 관련 연구도 미비하다. 이에 본 연구는 금속 입자가 함유된 필라멘트의 물성과 방사선의 차폐능력을 평가하여 3D 프린트를 이용한 방사선 차폐체 개발의 기초자료를 제공하고자 한다. 금속입자 강화재가 함유된 금속 필라멘트 5가지를 선정 후 ASTM의 평가방법을 이용하여 인장강도, 밀도, XRD, 무게측정 등 물성을 평가하고 방사선 차폐능력을 알아보기 위하여 한국산업표준의 방호용구류 시험방법에 따라서 방사선 차폐율을 구하였다. 인장강도는 PLA + SS가 가장 높았고 ABS + W가 가장 낮았으며 밀도는 ABS + W 가 3.13 g/cm3으로 가장 높게 나타났다. XRD결과 시편의 표면의 입자의 XRD peak 패턴이 각 입자 강화재 분말 금속의 패턴과 일치함을 확인 할 수 있어 프린트된 시편이 분말금속이 함유 되었음을 확인하였다. 3D 프린트 복합 필라멘트별 차폐효과는 ABS + W, ABS + Bi, PLA + SS, PLA + Cu, PLA + Al의 순서로 실효원자번호와 밀도에 비례하여 차폐율이 높게 나타났다. 본 연구에서는 강화재로 금속 분말이 함유된 금속입자 복합 필라멘트는 방사선의 차폐능력을 가지는 것이 확인되었으며 향후 방사선 차폐용 필라멘트의 사용가능성을 확인하였다. It is hard to get Filaments which are materials of the 3D printing Fused Deposition Modeling(FDM) method as radiation shielding in Korea. and also related research is insufficient. This study aims to provide basic data for the development of radiation shields using 3D printing by evaluating the physical properties and radiation shielding capabilities of filaments containing metal particles. after selecting five metal filaments containing metal particle reinforcement materials, the radiation shielding rate was calculated according to the Korean Industrial Standard s protective equipment test method to evaluate physical properties such as tensile strength, density, X-ray Diffraction(XRD), and weight measurement using ASTM s evaluation method. In the tensile strength evaluation, PLA + SS was the highest, ABS + W was the lowest, and ABS + W is 3.13 g/cm3 which value was the highest among the composite filaments in the density evaluation. As a result of the XRD, it may be confirmed that the XRD peak pattern of the particles on the surface of the specimen coincides with the pattern of each particle reinforcing material powder metal, and thus it was confirmed that the printed specimen contained powder metal. The shielding effect for each 3D printed composite filament was found to have a high shielding rate in proportion to the effective atomic number and density in the order of ABS + W, ABS + Bi, PLA+SS, PLA + Cu, and PLA + Al. In this study, it was confirmed that the metal particle composite filament containing metal powder as a reinforcing material has radiation shielding ability, and the possibility of using a radiation shielding filament in the future.

3D printing으로 제작된 금속 코어와 치과용 도재 간의 전단결합강도 평가

정재관(Jung, Jae-Kwan),이수옥(Lee, Su-Ok),김기백(Kim, Ki-Baek) 한국산학기술학회 2015 한국산학기술학회논문지 Vol.16 No.4

3D 프린팅 기술은 최근 치과용 보철물 제작 기술로 도입이 되었다. 본 연구의 목적은 3D 프린팅 기술에 의해 제작된 금속 코어와 상부 도재와의 전단결합강도를 평가하는 것이다. 본 연구를 위해 30개의 금속 코어를 제작하였다(cast 15개, 3D printing 15개). 금속 코어에 치과용 도재를 축성하여 시편 제작을 완료하였다. 완성된 시편의 전단결합강도는 crosshead speed 1mm/min으로 하중을 가하여 측정하였으며, 두 그룹의 전단결합강도 값 사이에는 통계적으로 유의한지 알아보기 위하여 Mann-Whitney test를 이용하였다(유의수준 0.05). 측정이 끝난 후 시편을 대상으로 파절양상을 분석하였다. 본 연구를 위한 실험 설계, 금속 코어 제작, 도재 축성 등의 시편 제작부터 실험 수행과 수행 후 실험 데이터 분석과 통계 분석 그리고 파절된 시편을 대상으로 한 파절 양상 분석까지 총 6개월이 소요되었다. 실험 결과 cast 50.14, 3D printing 54.36 MPa를 갖는 것으로 조사되었고, 통계적으로도 유의하였다. 파절양상은 두 집단 모두 시편의 대부분이 혼합형 파절양상을 보였다. 이와 같은 결과 들로 미루어볼 때 3D 프린팅에 의해 제작된 금속도재관 제작을 위한 금속 코어는 임상적으로 허용이 가능할 것으로 사료된다. The purpose of this study was to evaluate the shear bond strength between metal core fabricated by 3D printing and dental porcelain. Thirty metal cores were fabricated(cast 15ea, 3D printing 15ea). The porcelain for each group was builded to the metal core. Sample was loaded to shear force(crosshead speed 1mm/min) in a universal material testing machine. The fracture samples were analyzed failure aspect. The means were statistical analyzed using by Mann-whitney test(α=0.05). The period of experimental(metal cores fabrication, dental porcelain build up, data analysis, statistical analysis, failure aspect analysis and others) for this study took six months. The mean±SDs of shear bond strength was 50.14±1.60MPa for the cast group, and 54.36±3.18MPa for the 3D printing group(p=0.035). The failure aspect showed mixed failure. As a results, metal cores fabricated by 3D printing method were clinically acceptable range.

유압프레스와 3D 프린팅을 활용한 장신구 제작 방법 연구

임병덕,차경철 사단법인 한국조형디자인협회 2023 조형디자인연구 Vol.26 No.3

금속공예 분야 또한 4차 산업 혁명의 핵심 중의 하나인 3D 프린팅 활용이 계속 증가하고 있다. 현재 장신구 제작에 가장 많이 사용되고 있는데 가장 큰 이유는 고가였던 장비 가격이 많이 저렴해졌고 여기에 특허권의 만료로 인해 다양한 회사에서 신제품들이 개발되고 있다. 이런 상황에서 본 연구자는 금속공예 작업에 3D 프린팅 활용 범위를 좀 더 넓히기 위해 작업 특성상 단순한 입체감 표현이 가능했던 유압프레스 작업에 3D 프린팅을 활용하였다. 기존 유압프레스 작업은 형틀 제작에 금속이나 아크릴을 CNC 가공이나 레이저 커팅, 수작업 등으로 가공하여 사용했기 때문에 단순한 디자인이 대부분이고 여기에 디자인 난이도에 따라 시간이나 비용이 늘어나는 등 여러 가지 어려움이 많았다. 그래서 본 논문에서는 3D 프린팅 장비 중에서 가장 저렴하고 상대적으로 접근이 쉬운 FDM 3D 프린터로 제작한 형틀이 유압프레스 작업에 활용이 가능한지와 가능하다면 어느 정도까지 다앙한 볼륨 형태를 표현할 수 있는지 가능성을 확인하고자 하였다. 형틀을 제작할 소재인 필라멘트 또한 종류가 많이 있지만 모든 소재를 다루기에는 많은 시간상 제약이 있어서 가장 대중화된 ABS와 PLA 소재를 주로 하여 진행하였다. 유압프레스는 부피감 있는 형상 표현이 유리한 작업이므로 장신구 품목 중 펜던트를 선택하였고 이것을 이용하여 입체감 있는 하트 펜던트 장신구를 제작하였다. 실험 결과물을 보면 출력된 형틀의 외벽 두께와 내부를 채우는 밀도 등에 따라 유압프레스 작업의 결과가 달라졌는데 필라멘트 소재가 가지고 있는 기본 강도에 따라서 달라질 수도 있었고 장신구를 제작하는 판재의 두께나 재료에 따라서도 결과물에 차이를 확인하였다. 그래서 본 연구를 통해 금속공예 작업에 3D 프린팅을 활용하여 좀 더 다양한 작품이나 제품을 제작하는데 조금이나마 도움이 되길 기대해 본다. The use of 3D printing in metalworking, which is also one of the core components of the Fourth Industrial Revolution, continues to increase. It is currently being used most frequently in the production of jewelry, and the biggest reason for this is that the high cost of equipment has become much cheaper, and various companies are developing new products due to the expiration of patents. In this situation, the researcher used 3D printing in hydraulic press work, which was limited to simple volume representation due to its characteristics. In conventional hydraulic press work, metals or acrylics were processed by CNC machining or laser cutting, manual work, etc., so most designs were simple, and there were many difficulties such a increased time or cost depending on the design difficulty. Therefore, this paper aimed to confirm whether a mold made with the FDM 3D printer, which is the cheapest and relatively easy-to-use 3D printing equipment among 3D printing equipment, can be used in hydraulic press work and how much volume shape can be expressed if possible. The filament used to make the mold was mainly ABS and PLA, which are widely popularized materials, because there were many time constraints to handle all materials. The hydraulic press is advantageous for creating voluminous shapes, so the researcher chose a pendant among the jewelry items and created a voluminous heart pendant using it. According to the experiment results, the output of hydraulic press work varied depending on factors such as the thickness of the outer wall of the mold and the density of the material used to fill the inside. The basic strength of the filament material could also affect the results. The thickness of the substrate used to make jewelry or the material used could also affect the results. Therefore, through this research, it is hoped that 3D printing can be used in metalworking to create more diverse works and products.

스테인리스강을 사용한 분말 적층 용융 방식의 금속 3차원 프린터에서 제작된 물체의 최소 선폭 측정

손봉국(BongKuk Son),정연홍(Youn Hong Jeong),조재흥(Jae Heung Jo) 한국산학기술학회 2018 한국산학기술학회논문지 Vol.19 No.10

금속 3D 프린팅 기술은 레이저 빔의 초점에 금속분말을 주입하는 방식에 따라 대표적으로 PBF(Powder Bed Fusion) 방식과 DED(Direct Energy Deposition)방식으로 나뉜다. DED 방식은 금속 분말 도포와 동시에 레이저를 조사하여 3차원 구조물을 제작하는 금속 3D 프린팅 기술이고, PBF 방식은 일정 높이로 3차원 그래픽을 슬라이싱 한 후 한 층씩 금속 분말을 적층하여 레이저를 이용해 3차원 구조물을 제조하는 방식이다. DED 방식을 사용하면 레이저 클래딩, 금속 용접 등에는 강점을 가지지만 3D 형상을 제작할 경우 밀도가 낮아지는 문제점이 발생한다. DED 방식에서의 구조체 밀도 문제를 해결하기 위해 PBF 방식을 도입하면 상대적으로 밀도가 높은 3차원 구조물을 제작하는데 용이하다. 본 논문에서는 갈바노 스캐너와 광섬유로 전송되는 Nd:YAG 레이저 빔을 이용한 약 30 ㎛ 크기의 스테인리스 강 분말을 이용하는 PBF 방식의 3차원 프린터를 제작하고, 이를 이용하여 얇은 금속 구조물을 제작하였다. 또한 레이저의 조사 횟수, 출력, 초점 크기, 스캐닝 속도에 따른 선폭의 최적조건을 찾았으며, 그 결과 최적 조건은 레이저 조사 횟수 2회, 출력 30 W, 초점 크기 28.7 ㎛, 스캐닝 속도 200 mm/s에서 최소 선폭은 약 85.3 ㎛로 측정되었다. Metal three-dimensional (3D) printing technologies are mainly classified as powder bed fusion (PBF) and direct energy deposition (DED) methods according to the method of application of a laser beam to metallic powder. The DED method can be used to fabricate fine and hard 3D metallic structures by applying a strong laser beam to a thin layer of metallic powder. The PBF method involves slicing 3D graphics to be a certain height, laminating metal powders, and making a 3D structure using a laser. While the DED method has advantages such as laser cladding and metallic welding, it causes problems with low density when 3D shapes are created. The PBF method was introduced to address the structural density issues in the DED method and makes it easier to produce relatively dense 3D structures. In this paper, thin lines were produced by using PBF 3D printers with stainless-steel powder of roughly 30 ㎛ in diameter with a galvano scanner and fiber-transferred Nd:YAG laser beam. Experiments were carried out to find the optimal conditions for the width of a line depending on the processing times, laser power, spot size, and scan speed. The optimal conditions were two scanning processes in one line structure with a laser power of 30 W, spot size of 28.7 ㎛, and scan speed of 200 mm/s. With these conditions, a minimum width of about 85.3 ㎛ was obtained.

Comparison of Fitness of Metal Copings Manufactured by Wax Milling and 3D Printing

nam joong Kim,Seung-Min Park 대한예방치과학회 2023 International Journal of Clinical Preventive Denti Vol.19 No.4

Objective: In this study, the coping was manufactured using wax milling and additive manufacturing using 3D printing (DLP) for a design with internal values set in a CAD program. Metal copings were manufactured through burial, recall, and casting of the processed copings using conventional methods, and the internal suitability was compared and evaluated. Methods: The maxillary first molar was selected as an abutment test specimen model, and 35 abutment test specimens were produced with cemented carbide plaster. Wax coping was produced by cutting a wax block using a milling machine, and a castable resin pattern was produced using a printer. Burial, casting, and fitting were carried out according to traditionalmethods. Citing the silicon replica technique, the soft silicone thickness of the four cusps and the buccal and lingual margins was measured using the ‘2D cross-section’ function of the design program. Results: Margin fitness was measured from 0.027 mm to 0.037 mm for the metal coping of wax milling and 0.025 mm to 0.034 mm for the metal coping of 3D printing. The inner spacing was measured from 0.095 mm to 0.239 mm for the metal coping of wax milling and 0.013 mm to 0.241 mm for the metal coping of 3D printing. Conclusion: The spacing at the margins was less than 50 micrometers for both of metal copings using wax milling and 3D printing respectively. For the four cusp points, the inner spacing of the metal coping of 3D printing was narrower than the metal coping of wax milling.

금속 3D 프린팅 공정 최적화를 통한 H13 공구강 조형체의 기계적 특성 향상

윤재철,최중호,이행나,김기봉,양상선,양동열,김용진,이창우,유지훈,Yun, Jaecheol,Choe, Jungho,Lee, Haengna,Kim, Ki-Bong,Yang, Sangsun,Yang, Dong-Yeol,Kim, Yong-Jin,Lee, Chang-Woo,Yu, Ji-Hun 한국분말야금학회 2017 한국분말재료학회지 (KPMI) Vol.24 No.3

In this study, H13 tool steel sculptures are built by a metal 3D printing process at various laser scan speeds. The properties of commercial H13 tool steel powders are confirmed for the metal 3D printing process used: powder bed fusion (PBF), which is a selective laser melting (SLM) process. Commercial H13 powder has an excellent flowability of 16.68 s/50 g with a Hausner ratio of 1.25 and a density of $7.68g/cm^3$. The sculptures are built with dimensions of $10{\times}10{\times}10mm^3$ in size using commercial H13 tool steel powder. The density measured by the Archimedes method is $7.64g/cm^3$, similar to the powder density of $7.68g/cm^3$. The hardness is measured by Rockwell hardness equipment 5 times to obtain a mean value of 54.28 HRC. The optimum process conditions in order to build the sculptures are a laser power of 90 W, a layer thickness of $25{\mu}m$, an overlap of 30%, and a laser scan speed of 200 mm/s.