• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.41 no.9
• /
• pp.839-844
• /
• 2017

In the past few years, three-dimensional (3D) printing has been developed as a rapid prototyping (RP) technique. The fused deposition modeling (FDM)-type 3D printing is one of the most useful RP methods; however, it still has several disadvantages, such as low conductivity, heat degradation, and low surface quality. In this study, test specimens are fabricated using an FDM-type 3D printer with an ABS material. Then, the specimens undergo post-processing on submerging in acetone with various processing times. As the processing time increases, surface roughness is enhanced significantly within the first five seconds by chemical processing, following which the processing effects are reduced. Furthermore, post processing causes the ultimate strength and strain to increase slightly with increased processing time.

• Korean Journal of Optics and Photonics
• /
• v.28 no.5
• /
• pp.213-220
• /
• 2017

This paper proposes how to fabricate an educational Mach-Zehnder interferometer that is easy to align and inexpensive, using 3D printers and semiconductor lasers. The interferometer consists of a body $165mm{\times}120mm{\times}57mm$ in size, mirror mounts, a laser holder, beam splitters, and so on. The laser path is adjusted by 4 mirror mounts, each comprised of rubber bands, small metal wires, and a screw. The interference fringe is enlarged by the lens at the final stage. The refractive index of a slide glass was measured by counting the number of moving interference fringes while the slide glass, inserted into one of the two interferometer arms, is rotating. The formula for the refractive index as a function of the optical-path difference and rotation angle was obtained, and used to calculate the refractive index of glass from the interferometer experiment. The use of a rotating glass in one arm of the interferometer nullifies the need for a precision stage, which despite its high cost is often required to observe the moving interference fringe in the classroom. Therefore, the 3D-printed Mach-Zehnder interferometer proposed in this paper can be very useful for education, because of its affordability and performance. It enables students to perform both qualitative and quantitative studies using a 3D-printed interferometer, such as measuring the refractive index of a glass sample, and the wavelength of light.

• Journal of the Korean Society for Precision Engineering
• /
• v.34 no.4
• /
• pp.293-298
• /
• 2017

In this study, we developed a 3D chocolate printer and studied the conditions needed for chocolate printing. Because chocolate is a mixture of cocoa mass, cocoa butter and sugar particles, its properties vary with temperature, and care is required in melting and extrusion. A chocolate supply unit is composed of a heating block and a syringe pump. It is integrated with a 3-axis linear robot. In order to be more accurate than the existing 3D chocolate printer is, the system was configured so that the printing line width became $430{\mu}m$. Printing performance was studied according to various parameters. The condition needed for printing lines with a stable width was discovered by the experimental design method and has been confirmed by a 2D line test. These 3D printing experiments showed that it was possible to build a 3D shape with an inclination angle of up to $45^{\circ}$ without support. Further, chocolate printing of a 3D shape has been successfully verified with the developed system.

• Proceedings of the Korean Information Science Society Conference
• /
• 2012.06c
• /
• pp.320-322
• /
• 2012

코 내부의 복잡한 기하학적 형상으로 인해 nasal airway의 분리는 많은 어려움을 겪고 있다. 본 논문은 velocimetry of nasal airflow 와 코 수술 계획을 위하여 3차원 공간에서 nasal airway를 interactive semiautomatic으로 분리하고 시각화하는 방법을 제안한다. 제안하는 방법은 ROI(Region-Of-Interest)와 multi-seed 3d region growing(MS3RG)기법을 적용하여 비강을 분리하며 볼륨렌더링 기법을 이용하여 분리된 영역을 3차원 공간에서 직관적으로 확인 할 수 있다. 또한 분리된 3차원 비강 모델은 유동흐름 실험을 위하여 3차원 프린터를 통해 실제 모형으로 제작 가능하다. 그리하여 CT dataset(512*512*175)을 가지고 매뉴얼 세그멘테이션에서 5시간 정도 걸리던 작업을 반자동 세그멘테이션 방법을 이용할 경우 최대 3분 이내에 분리 작업을 완료할 수 있으며 수치해석 실험 및 물리 실험에 이용할 수 있다.

• Journal of Energy Engineering
• /
• v.29 no.1
• /
• pp.75-84
• /
• 2020

This study investigates a simple, yet effective and affordable, manufacturing method to increase the electrical efficiency by triboelectric generator (TEG) applying 3D printers. In this study, we propose the newly manufacturing method for producing a macroscale surface patterning. Overall experiments were conducted in designed test-bed chamber system which can control the magnitude and frequency of the frictional force and the relative humidity. Furthermore, we can demonstrate the voltage enhancement of macroscale surface patterns about 1.6-fold. The peak voltage producing by TEG was as high as 18 V. In comparison with conventional process that employ micro- and nanoscale patterns, the proposed process by 3D printer is faster and more suitable for mass production.

• Journal of the Korean Society for Precision Engineering
• /
• v.23 no.8 s.185
• /
• pp.203-210
• /
• 2006

This paper focuses on the development of RT technology suitable for manufacturing a small quantity of metal prototype of a precise part from an RP master. Dimensional accuracy and surface roughness are evaluated from Thermojet part of a 3D printer, and effective post-processing method is introduced. Investment casting is done using a prototype built from 3D printer as a wax pattern. Ceramic shell investment casting technique is developed to build a prototype with materials mostly wanted. Also, experimental result shows this research is very useful in manufacturing of a small quantity of functional part or a test part of a specific material.

• Journal of Korea Society of Industrial Information Systems
• /
• v.20 no.3
• /
• pp.81-86
• /
• 2015

We fabricated a 3D knee joint model through the imaging processing. The 3D shape information is different depends on specific conditions when the shape of real knee joint is extracted from CT/MRI sliced images. The two types of joint models were fabricated by using 3D printer in order to analysis of joint movement by slight difference of 3D shape information. The compressive force experiments were performed by using knee joint model. As the results, the compressive forces were changed with respect to the difference of geometry. Consequently, feasibility test should be performed before developing biomimetic bioreactor.

• Journal of radiological science and technology
• /
• v.40 no.3
• /
• pp.433-441
• /
• 2017

The 3D printing selective laser sintering (SLS) and stereo lithography apparatus (SLA) method used for bone model production has good precision and resolution, but the printers are expensive and need professional knowledge for operation. The program that converts computed tomography digital imaging and communications in medicine (DICOM) file into STL (stereolithography) file is also expensive so requesting 3D printing companies takes a lot of time and cost, which is why they are not generally utilized in surgery. To produce bone models of fractured patients, the use of 3D imaging conversion program and 3D printing system should be convenient, and the cost of device and operation should be low. Besides, they should be able to produce big size bone models for application to surgery. Therefore, by using an fused deposition modeling (FDM) method 3D printer that uses thermoplastic materials such as DICOM Viewer OsiriX and plastic wires, this study developed 3D printing system for Fracture surgery Patients customized bone model production for many clinics to use for surgery of fracture patients by universalizing with no limit in printing sizes and low maintenance and production cost. It is expected to be widely applied to the overall areas of orthopedics' education, research and clinic. It is also expected to be conveniently used in not only university hospitals but also regular general hospitals.

• Journal of KIBIM
• /
• v.7 no.1
• /
• pp.1-8
• /
• 2017

Aesthetic design guidelines of bridges were developed in many countries. As iconic structures, bridges need to be attractive and durable as they serve many generations. In this paper, a new design process of concrete structures considering 3D shapes and texture was proposed. The 3D design needs to consider function, economy, advanced technology, tradition and local culture. 3D printers enable the combination of artistic design and engineering design for concrete structures. Parametric modeling with iconic design was utilized to produce 3D formworks. As a pilot project, a railway bridge girder was designed and the proposed technologies were applied. Detail requirements to improve constructability and quality of concrete surfaces were derived. From the pilot applications, design guidelines were suggested.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.24 no.3
• /
• pp.233-238
• /
• 2014

Creativity is crucial in designing and producing attractive accessaries and daily supplies as well as art works. Generative design can be a paradigm to be used to obtain novel ideas or motifs for creative design works. This paper introduces a generative design method which comes up with unique ring models using genetic algorithm. It presents how the genetic algorithm works in terms of candidate solution coding, operators, and fitness evaluation function. The proposed method allows the customers to express their personal preference and later the preference to be reflected in fitness evaluation. In the final stage of the proposed method, several ring models are suggested for customers to choose on their own. The chosen ring models can be put into physical rings with the help of a 3D printer because the models are expressed in 3D geometric structures.