• Korean Journal of Computational Design and Engineering
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• v.21 no.3
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• pp.224-233
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• 2016

We propose a new method to visualize 3D models for FDM (Fused Deposition. Modeling) printing that appearance of the printed results can be predicted more realistically as that the efficiency of the modeling-printing process can be improved. The layered nature of horizontal slicing and the vibratory nozzle movements of customer-level FDM 3D printers leaving the characteristic patterns of noisy stripes on the surfaces of printed objects make difficulties in prediction of printed result in company with the thermal contraction of filament material. First, our method analyses the G-codes generated by common slicers to obtain proper outlines and take advantages of a modified version of Perlin noise based texturing method for rendering efficiency and enough number of control parameters on the visual details. The results show improved rendering details of pre-visualization of FDM printing.

• Advances in aircraft and spacecraft science
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• v.9 no.4
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• pp.301-318
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• 2022

This paper presents the free vibration analysis of 3D printed sandwich beams by using high-order theories based on the Carrera Unified Formulation (CUF). In particular, the component-wise (CW) approach is adopted to achieve a high fidelity model of the printed part. The present model has been used to build an accurate database for collecting first natural frequency of the beams, then predicting Young's modulus based on an inverse problem formulation. The database is built from a set of randomly generated material properties of various values of modulus of elasticity. The inverse problem then allows finding the elastic modulus of the input parameters starting from the information on the required set of the output achieved experimentally. The natural frequencies evaluated during the experimental test acquired using a Digital Image Correlation method have been compared with the results obtained by the means of CUF-CW model. The results obtained from the free-vibration analysis of the FDM beams, performed by higher-order one-dimensional models contained in CUF, are compared with ABAQUS results both first five natural frequency and degree of freedoms. The results have shown that the proposed 1D approach can provide 3D accuracy, in terms of free vibration analysis of FDM printed sandwich beams with a significant reduction in the computational costs.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1869-1872
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• 2003

As SLA(Sterealithography), SLS(Selective Laser Sintering), LOM(Laminated Object Manufacturing), FDM(Fused Deposition Modeling) etc. The FDM system the heart of a study and is developed by Stratasys co. ltd, in US., is small and cheap R.P. The material filament is heated until the material reaches a near-liquid state, it is pumped through a nozzle and become hand with a shape required, and this nozzle move pumping on the previously deposited material. Such FDM system that choice deposition type with X-Y plouter obtain in the thin continue layer by decreasing amount of extrusion or to central the injection amount when the head slow down at the corner, but in the process that fusion wax or resin become hand, deformation occur and it will affect the shape accuracy and the surface roughness. Such effect will depreciate quality and reliability of the product. Therefore, when the product made in actuality, the fundamental study on the basis geometry(surface, volume, line, angle) must be preceded and it have been research by many Free Form Fabrication. So, this basic object study purpose to obtain the fundamental geometry data and to enhance the surface roughness of the shape. And an operant can use the data for the progress of the surface roughness. This study research the estimation and application of the prototype surface roughness by adjustment the injection amount. And basie of this research, describe the pattern of prototype surface roughness and also used the result to estimate the surface of prototype.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.2
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• pp.313-318
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• 2020

Since the engineering plastics having a melting point of higher than 300 degrees have a high mechanical rigidity, chemical resistance, friction and abrasion performance, those are being highlighted as metal replacement materials in various industries. In this study, 3D printer nozzle with excellent heat dissipation characteristics are designed and analytically verified to form engineering plastics with high melting points in 3D printers based on the melt-lamination modeling method. In order to insulate between the heat block heated to a melting point of filament material and the upper part of the nozzle where the filament is transferred, the heat brake part with low thermal conductivity was designed to have two separate parts, and a cooling fin structure is further applied to the heat brake part to lower steady-state temperature by air convection. Optimized structural design on FDM nozzle part reduces the temperature at the heat sink and at the end part of heat brake by 50% and 14% respectively, compared to the conventional BCnozzle structure.

• Korean Journal of Construction Engineering and Management
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• v.21 no.2
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• pp.3-14
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• 2020

This study reviews and comparatively analyzes existing classification systems for 3D concrete printers to propose a classification system for 3D concrete printers. Several classifications for existing 3D printers have been proposed and used in the market. Nevertheless, quite a few of the printer types such as fused deposition modeling (FDM) and selective laser melting (SLM) are not suitable for characterizing 3D concrete printers. To derive the properties that distinguish one 3D concrete printer type from the others, this study reviews existing 3D concrete printers and comparatively analyzes the properties of 3D concrete printers identified in previous studies. The results show that existing classifications do not reflect the states-of-the-art of 3D concrete printers, the classification terms are ambiguous, and the entire printing processes are not considered. A new classification system was proposed based on the essential properties of the 3D concrete printers identified through the analysis of related work. The result of this study can be used as a basis for classifying commercial 3D concrete printers as well as studies related to 3D concrete printers.

• Journal of radiological science and technology
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• v.40 no.3
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• pp.433-441
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• 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 the Korea Academia-Industrial cooperation Society
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• v.9 no.4
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• pp.892-898
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• 2008

3D rapid prototyping is the manufacturing technology to fabricate a prototype with the data stored in a computer, which differs from conventional casting technology in terms of an additive process. Various 3D rapid prototyping techniques such as stereolithograpy. fused deposition modeling. selective laser sintering, laminated object manufacturing have been developed but among them, 3D inkjet printing has a unique feature that materials could be jetted to directly form the body of a prototype, which could be a finished product functionally and structurally. However, this needs ink with a high solid content, which tends to increase the dynamic viscosity of ink. The increase of ink viscositytends to restrict the jettable range of ink and hence the jetting conditions should be optimized. The intrinsic speed of sound in a hot melt ink with ceramic nanoparticles dispersed is one of key components to determine the jettable range of ink. In this paper, the way to measure the intrinsic speed of sound in a hot melt ceramic ink is proposed and its influence on the jetting condition is discussed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.30-33
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• 2003

In this paper the advantage of web technology applied to Rapid Prototyping is discussed. Two fabrication processes are chosen to be web-enabled. One, a post-process of FDM is developed to provide translucent plastic parts made of medical grade ABS material. The other, a system to fabricate laser machined Light Guide Panel is developed. In order to show the timesaving characteristics of the web-based tools, two websites are implemented (http://nano.gsnu.ac.kr/fdm ＆ http://nano.gsnu.ac.kr/laser). The 3-tier architecture is applied for the Internet communication between designers and manufacturing sites, The integrated design tools and physical manufacturing processes enable designers to submit a new design and to receive the fabricated parts in an expedited manner. Example parts are fabricated using the web-based system to prove the concept of the web-based design and Rapid Prototyping.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.142-144
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• 2016

Recent promising technologies of the manufacturing sector interest, and the interest in 3D printing that is expected to cause a huge ripple effect rapidly, and various types of products advertised in accordance with the falling price of 3D printers is spreading. However, the personal 3D printers that are currently being advertised is used for Injection output of the simple type that does not require a high processing precision in accordance with the limitation of technical performance, and consumer satisfaction is very low. In this paper, we propose a 3D printer, 3D precision to overcome existing limitations in the way the printer's high SLA 3D printer that combines injection method and the LSU (Laser Scanning Unit) in the office laser printer polygon mirror scanning method. 3D printers which are proposed to improve the accuracy and manufacturing speed is expected to replace the existing entry-level 3D printer.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.7
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• pp.83-89
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• 2019

In the conventional casting and forging method, there is a disadvantage that a mold is an essential addition, and a production cost is increased when a small quantity is produced. In order to overcome this disadvantage, a metal 3D printing production method capable of directly forming a shape without a mold frame is mainly used. In particular, overseas research has been conducted on various materials, one of which is a metal printer. Similarly, domestic companies are also concentrating on the metal printer market. However, In this case of the conventional metal 3D printing method, it is difficult to meet the needs of the industry because of the high cost of materials, equipment and maintenance for product strength and production. To compensate for these weaknesses, printers have been developed that can be manufactured using sand mold, but they are not accessible to the printer company and are expensive to machine. Therefore, it is necessary to supply three-dimensional casting printers capable of metal molding by producing molds instead of conventional metal 3D printing methods. In this study, we intend to reduce the unit price by replacing the printing method used in the sand casting printer with the FDM method. In addition, Ag paste is used to design the output conditions and enable ceramic printing.