주얼리 디자인 제작에 활용되는 3D 프린팅 기술 비교 연구

위경효(Whi, Koung-hyo) 한국조형디자인학회 2014 조형디자인연구 Vol.17 No.1

3D 프린팅은 컴퓨터로 설계된 3D 모델링 또는 3차원 스캐너를 통해 획득된 솔리드(Solid) 상태의 모델 데이터를 한층 한층(Layer by Layer) 기계적 적층을 통하여 손으로 만질 수 있는 물리적 형상(Physical Model)으로 빠르게 제조하는 기술로 정의된다. 이러한 3D 프린팅 기술은 현재의 금형공정으로는 제조할 수 없는 어떠한 디자인 형상이라도 제작할 수 있다. 1986년 미국의 Charles W. Hull에 의해 광경화성수지 적층방식(SLA:Stereo lithography)이 발명되었으며 1987년 첫 상용화 3D 프린팅 장비가 출현한 지 약 30여 년이 된 지금 3D 프린팅은 공정 기술, 재료, 소프트웨어, 관련 인프라 등의 비약적인 발전을 거듭해 과거에는 상상하지 못했던 디자인과 제조기술의 혁신 및 인간의 삶을 변화시킬 핵심 기술로 부상하고 있다. 2012년 영국의 경제 주간지 이코노미스트(Economist)는 '3차 산업혁명(The third industrial revolution)'이라는 특별 리포트를 통해 3D 프린팅 기술이 내연기관과 컴퓨터에 이어 3차 산업혁명을 이끌 것으로 예측하였다. 2013년 미국 오바마(Barack Hussein Obama) 대통령도 '3D 프린팅 기술은 거의 모든 것을 만들 수 있는 제조 혁명을 가져다줄 잠재력을 지닌 기술'로 언급했다. 이러한 3D 프린팅 기술은 현재 SLA(Stereo Lithography), SLS(Selective Laser Sintering), FDM(Fused Deposition Modeling), DLP(Digital Light Processing), Polyjet등 20여 가지의 방식과 시스템이 활발히 사용되고 있다. 사용 재료로는 금, 은, 동, 티타늄, 스테인리스를 포함한 금속, 플라스틱, 실리콘, 고무, 나무, 콘크리트에서 바이오, 음식 재료까지 가능하다. 3D 프린팅 기술의 활용분야는 소비자 전자 제품을 비롯한 자동차, 우주 항공, 의료 덴탈, 군사(국방), 건축, 교육, 디자인에 이르기까지 매우 다양하다. 이에 본 연구에서는 3D 프린팅 기술이 거의 모든 산업에 영향을 준다는 의미에서 주얼리 디자인 분야에서의 3D 프린팅 기술의 활용 가능성과 방법을 찾고 나아가 더욱 혁신적인 디자인과 상품개발에 효율성을 높이기 위한 연구의 의미가 있다. 이를 위해 주얼리 산업에 적합한 3D 프린팅 방식들을 추출하고 비교 분석하여 현재와 앞으로 기술에 대한 경향을 파악했다. 또한, 방식별 결과물의 디자인적 특징과 장.단점을 비교 했다. 끝으로 3D 프린팅 기술의 활용을 위한 한국의 주얼리 디자인 및 산업에서 준비해야 할 과제와 방향을 제시했다. 이것은 곳 영세성을 면치 못하는 한국 장신구 산업구조의 틀을 바꾸고 국제 경쟁력을 갖추기 위한 산업 활성화의 실마리가 될 것으로 기대한다. Three dimensional (3D) printing technology is defined as techniques of rapidly manufacturing a solid state of model data obtained through computer-designed 3D modelings or through 3D scanners into physical models that can be directly touched by hand by means of the mechanical (layer by layer) stacking processes. The aforementioned 3D printing technology makes it possible to manufacture any designed shape that was not made by a presently available molding process. In 1986, the photo-polymer resin stereolithography accumulation (SLA) method was invented by Charles W. in US. Since the first commercially available 3D printing equipment appeared in 1987, the 3D printing techniques have made rapid and repeated developments in various areas such as processing technologies, materials, softwares and related infrastructures for the past 30 years. The 3D printing has emerged as a key technology that will bring unprecedented innovations in the designing and manufacturing processes and some changes in human life that were not imagined in the past. In 2012, Economist, the UK weekly economy magazine, made a special report titled 'the third industrial revolution' where the 3D printing technology was predicted to lead the third industrial revolution followed by the internal combustion engines and computers. In 2013, US president Obama (Baraack Hussein Obama) said that the 3D printing technology had a great potential that would bring a revolution in the manufacturing processes as it would make it possible to manufacture almost all the things. In the above-mentioned 3D printing technology, approximately 20 methods and systems such as SLA (tereolithography), SLS (Selective Laser Sinterimg), FDM (Fused Deposition Modeling), DLP (Digital Light Processing), Polyjet and the like are currently in active use. A variety of materials are used in the 3D printing technology, for example, gold, silver, copper, titanium, metals including stainless steel, plastic, silicone, rubber, wood, concrete, bio-materials, even food ingredients. Besides, the application fields of the 3D printing technology are in a wide range covering consumer electronic products, automotive, aerospace, medical and dental devices, military (defense) equipment, architectural models and educational and designing tools. This study was meaningful in that it intended to find the potential usability and methods of 3D printing technologies in the field of fashion jewelry design, and to enhance the efficiency of innovative design and product development considering that 3D printing technologies influence almost all industries. To achieve these goals, the study investigated the trends between current and future technologies by extracting and comparing different methods of the 3D printing technology suitable for jewelry industry. Moreover, the design features and advantages and disadvantages of the fashion jewelry products resulting from various methods were analyzed. The study proposed the future challenges and directions for the Korea fashion jewelry designing and industry to utilize 3D printing technology. The effort made in this study is expected to change the framework of Korea jewelry industry structure, which has remained in its small-scale business up to now, and take a beginning step of the industrial activation to secure the international competitiveness.

정하중을 받는 구조물의 적층 제조를 위한 적응적 가중치 적용 동시 위상최적설계

조재훈(Jae Hun Jo),이중석(Joong Seok Lee) 대한기계학회 2021 大韓機械學會論文集A Vol.45 No.9

적층 제조는 전통적인 방식에서는 구현하기 어려운 복잡한 설계의 구조물을 효과적으로 제작할 수 있는 장점을 가지고 있다. 반면에 구조물 전체를 순차적으로 적층하여 제조하기 때문에 공간적으로 돌출되거나 떠있는 부분이 제조 과정에서 변형되거나 심지어 파괴되는 문제가 발생할 수 있다. 본 연구에서는 위상최적설계 기법을 이용하여 정하중을 받는 주 구조물과 적층 제조 과정에서 주 구조물의 자중을 떠받치는 역할을 하는 지지부를 동시에 설계한다. 위상최적설계 수식화에 있어 주 구조물과 지지부를 포함하는 전체 구조 간의 변형률에너지의 비를 목적함수 내의 다중 물리량의 상대적 중요도를 조절하는 적응적 가중치로 정의한다. 주 구조물과 지지부의 물성치를 정규화된 값으로 설정하여 다양한 설계 예제에 대하여 물성치의 변화에 따른 설계 결과에의 영향을 비교 분석한다. The additive manufacturing method has advantages for effectively manufacturing structures of complicated designs that are difficult to address by using traditional methods. Because the structure is built by sequential stacking entirely, however, the overhang or floating regions may be deformed or even fail during the additive manufacturing process. In this work, we design the main structure under a static load and the support parts for the main structure simultaneously using topology optimization for additive manufacturing. In the topology optimization formulation, the weighting factor determining the relative contribution of multiple quantities in the objective function is defined as a ratio of the strain energy of the main structure to that of the whole structure including support parts. By normalizing the material properties of the main structure and the support parts, the effects of the properties in the results are investigated for various design examples.

열반응형 4D 프린팅을 적용한 곡면형 성형회로 부품 제작 연구

이주연,이민종,손용우,윤정훈,박근 대한기계학회 2023 大韓機械學會論文集A Vol.47 No.3

4D printing is an advanced application of 3D printing with additional shape changes over time, which deforms additively manufactured parts using external stimuli. In this study, a thermoresponsive 4D printing method was developed to fabricate a molded-interconnect device (MID) with a curved shape. For this purpose, a flat MID keypad was designed to contain conductive circuits in a nonconductive plastic base. The flat MID keypad frame was then additively manufactured using a material extrusion (ME)-type 3D printer, by interactively inserting several conductors during the printing process. In ME-type printing, printing paths were programmed to have planar thermal anisotropy and thus induce bending deformation under thermal stimuli. A curved fixture was designed to install a hot air gun and thus guide thermal deformation to have the desired curvature, from which a facile 4D printing method could be developed with high dimensional accuracy and repeatability. 4D 프린팅은 3D 프린팅 기술에 시간에 대한 형상 변화를 추가한 개념으로, 3D 프린팅으로 제작된 제품에 외부 자극을 가하여 형상을 변화시킨다. 본 연구에서는 열반응형 4D 프린팅 기술을 이용하여 곡면형 성형회로 부품(MID)을 제작하기 위한 기술을 개발하고자 한다. 이를 위해 플라스틱 몸체부 안에 금속 도선이 삽입된 평면형 MID 키패드를 설계하였고, 압출 적층형 3D 프린팅 공정을 사용하여 도선이 삽입된 플라스틱 키패드 프레임을 제작하였다. 특히 압출 적층형 프린팅에서 출력 경로를 인위적으로 조절함으로써 면내 열적 이방성을 부여하였으며, 열적 자극을 인가하여 굽힙 변형이 발생되도록 하였다. 상기 4D 프린팅 과정에서 원하는 곡률을 형성할 수 있도록 가열장치가 삽입된 고정구를 제작하여 사용하였으며, 결과적으로 높은 형상정밀도 및 반복재현성을 보장하는 4D 프린팅 기법을 개발하였다.

FEM 해석을 통한 표준 시편에 대한 금속 3D 적층 제조 공정 최적화 및 검증

염미정(Mi-jeong Yeom),이춘우(Chun-Woo Lee),남궁인(Ihn Namgung) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.4

금속 3D 프린팅 경우, 금속 분말 (PBF 방식의 경우)을 레이저 등의 열원을 사용하여 용융시키고 냉각하는 과정을 반복하는 공정의 특성 상 기존의 전통적인 제작 방식과는 다른 여러 문제를 가지고 있다. 대표적으로 내부 기공 발생으로 인한 기계적 물성 저하, 과도한 잔류 응력 및 열변형 등의 공정상 문제가 있다. 따라서 사용하는 소재 및 장비에 적합한 물성치를 구하는데 많은 시간과 비용이 소요된다. 이러한 문제를 해결하기 위해 컴퓨터를 사용한 AM 공정 시뮬레이션을 통해 적층 공정에 필요한 최적 변수를 구하여 실제 적층 공정의 시행착오를 획기적으로 줄일 수 있다. 본 연구에서는 ANSYS Additive Suite를 이용하여 AM 공정의 최적화를 수행하였다. ANSYS Additive Suite에서 제공되는 재료 물성치를 사용하여 단일 비드 성형 및 육방체 성형에 대한 다공성 시뮬레이션을 수행하여 적층공정의 중요한 변수인 레이저 파워, 스캔 속도, 해치 간격 등 공정 변수를 구한다. 이 변수를 활용하여 표준 시편을 장비에서 출력하고, SSF(변형률 스케일링 계수)와 ASC(이방성 변형률 계수) 값을 구한다. 이렇게 구한 변수들은 재료에 따라 달라지며 최종 적층 제조 시뮬레이션에 적용된다. 이 변수들를 사용하여도 최종 출력물은 열변형 및 서포트의 영향으로 요구되는 설계와 일치하지 않는다. 따라서 최소의 설계를 변경하여 보상설계 함으로써 열변형 및 서포트의 제거로 인한 변형을 상쇄할 수 있다. 본 연구에서는 적층 제조 공정 최적화와 표준 시편을 이용한 보상설계 방법에 대해 서술한다. Metal 3D printing works by repeated process of melting and cooling of metal powders(in case of PBF technology), and therefore it creates problems that are different from traditional manufacturing method. Typically, there are unwanted deformation and deterioration of mechanical properties due to the thermal deformation and porosity. The process of finding optimal AM parameters is also time-consuming and costly. We can dramatically reduce this trial and error process by simulating AM process in computer. In this study, ANSYS Additive Suite is used to optimize the AM process. Using ANSYS software and the material property provided in the software, single bead and porosity simulation is conducted to find out important process parameters such as laser power, scan speed, hatch spacing, etc. Next, standard specimen is fabricated using AM machine and obtain SSF (strain scaling factor) and the ASC (anisotropic strain factor) parameters. These parameters are specific to the material and are used in the final step of AM simulation. These parameters produces products that is affected by thermal deformation and supports and is different from original design. Hence compensation of original design is done to cancel out thermal deformation and deformation due to removal of supports. This study presents a simulation of AM process and design compensation method with standard specimen.

A Case Study on Productivity Innovation through Convergence of Sand 3D Printing Technology

한국현(Kuk-Hyun Han),백진욱(Jin-Wook Baek),박상윤(Sang Yun Park),임태완(Tae Wan Lim),박주민(Ju Min Park) Korean Society for Precision Engineering 2021 한국정밀공학회지 Vol.38 No.9

Recently, competition in the manufacturing industry related to the preoccupation of new markets has drastically changed due to the increase in small quantity batch production products. Besides, business models utilizing 3D printing technology suitable for flexible manufacturing are gaining interest. As 3D printing technology is becoming more common, Design for Additive Manufacturing is also in the spotlight. However, the productivity of 3D printing technology is still insufficient in terms of mass production. In this study, the possibility of innovation in mass production process that combines 3D printing technology is presented through the case of innovation in manufacturing productivity of medium-speed engine cylinder head through the integration of sand 3D printing technology. It outlines how sand 3D printing technology is applied to cylinder head mass production processes, how the quality of cylinder head products can be improved compared to conventional pattern-based molding methods, and how productivity can be maximized by reducing process time and human error through hybrid production method with sand 3D printed integrated design cores. In conclusion, this paper presents the effectiveness of sand 3D printing technology which can secure product competitiveness by increasing the production capacity of mass production process, reducing production costs, improving quality, and reducing loss.

적층 제조 기술의 소개 및 금속기반 적층 제조 활용을 위한 물성 평가 연구

박은주(Eunju Park),이문영(Moonyoung Lee),김남훈(Namhun Kim),허재성(Jae Sung Huh),이동호(Dong-Ho Rhee) 한국유체기계학회 2017 한국유체기계학회 학술대회 논문집 Vol.2017 No.12

Laser Assisted Additive Manufacturing by Rotating Metal Wire Feeder

김재구(Jaegu Kim),이창우(Chang-Woo Lee) Korean Society for Precision Engineering 2018 한국정밀공학회지 Vol.35 No.9

Chiefly, the metal wire-feed and laser additive manufacturing (AM) is a deposition process to produce larger mechanical parts required for aerospace, shipbuilding, automobile, and mold repair industries. The principal advantage of metal wire-feed AM is the high deposition rate compared to an assisted metal powder-feed AM, and metal powder-based fusion AM. During the wire-feed deposition process, the feed orientation is a critical parameter managed at all stages of processing. A better surface finish is attained when the melted wire flows smoothly through the process, and a wire feed direction that is utilized opposite to the deposition direction yields the best results. To improve the surface quality of metal 3D printing, we designed a rotating wire feeder, the feed direction of which varies with the direction of deposition; all free-form lines which thus exhibit identical surface qualities. Here, we use a rotating stage to orient the wire-feed direction according to the bead direction, a slip ring to supply electrical power to the feeder motor, and utilized two rotating channels on a plate to supply Ar gas and extract fumes safely during the processing stage. We evaluated the rotating wire feeder by building various parts as needed to the equipment.

3차원 프린팅을 이용한 무선전력전송의 안테나 설계 특성 규명

김지성(Ji-Sung Kim),박민규(Min-Kyu Park),이호(Ho Lee),김지언(Chiyen Kim) 한국기계가공학회 2020 한국기계가공학회지 Vol.19 No.8

The 3D printing of electronics has been a major application topics in additive manufacturing technology for a decade. In this paper, wireless power transfer (WPT) technology for 3D electronics is studied to supply electric power to its inner circuit. The principle of WPT is that electric power is induced at the recipient antenna coil under an alternating magnetic field. Importantly, the efficiency of WPT does rely on the design of the antenna coil shape. In 3D printed electronics, a flat antenna that can be placed on the printed plane within a layer of a 3D printed part is used, but provided a different antenna response compared to that of a conventional PCB antenna for NFC. This paper investigates the WPT response characteristics of a WPT antenna for 3D printed electronics associated with changes in its design elements. The effects of changing the antenna curvature and the gap between the wires were analyzed through experimental tests.

Development of 3-DOF Force Sensor Using Dual-Nozzle 3D Printing

백상우(Sang Woo Baek),구민석(Min Seok Gu),주용천(Yong Quan Zhou),조남규(Nahm Gyoo Cho) Korean Society for Precision Engineering 2020 한국정밀공학회지 Vol.37 No.10

In this paper, a multi-material non-assemble 3-DOF Force-Sensor was proposed and developed to improve the efficiency in the manufacturing. The PLA-Filament was used to produce the frame-structure and the elastic-deformation, and the conductive-PLA-filament, to produce a transducer. A dual-nozzle 3D-Printer was applied to produce the monolithic-structuretype force-sensor with the multi-materials simultaneously in single-manufacturing-process. The sensor was designed in a tripod-structure to detect the 3-DOF force-components in an external-force and a mechanical-interpretation was conducted on the elastic-deformation, which acts as a load-cell. The output model of a Wheatstone-bridge circuit-based transducer serving as a strain-gauge was also produced. A calibration-testing device, comprising a rotating stage, which turns with 2- DOF (θ, ϕ), was also developed to apply force in every direction. By conducting the calibration test, the relations between the input and output were computed in as a matrix and the resolution of the sensor was determined through the evaluation of linearity and stability deviations.

FDM 3D 프린팅에 의한 PLA 출력물의초음파 처리에 따른 기계적 특성 효과

박지혜,김수현,박지영,김주형 한국기계기술학회 2023 한국기계기술학회지 Vol.25 No.2

3D printing is widely used in product development and prototype manufacturing, and is expected to become universal across various industries with the development of 3D printing-related technologies. However, parts made by Fused Deposition Modeling(FDM) 3D printing using the commonly used stacking manufacturing process, show low tensile strength and hardness. The decreased mechanical properties of these parts limit their use as structural elements. In this study, we aim to investigate the relationship between ultrasonic treatment of PLA parts produced by FDM 3D printing and their mechanical properties. Specifically, we analyze the effects of ultrasonic annealing on the mechanical properties of PLA parts using the tensile test specimen.