• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.1
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• pp.66-73
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• 2021

In this paper, we analyzed and considered the precision of parts produced by 3D printing methods. For the latch systems applied to the Wingline folding doors, the 3D shape of the door hinge part was printed using FDM and DLP methods. Then, the 3D printed shape was scanned to measure the dimensions and dimensional changes of the actual model. In the comparison and analysis of the 3D printed door hinge parts, because the output filling density is 100% owing to the characteristics of DLP 3D printing, the filling density in FDM 3D printing was also set to 100%.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.3
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• pp.92-99
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• 2022

Owing to the excellent corrosion resistance of titanium alloys, they are widely used as materials for aircraft components. However, in terms of machining, dimensional deformation methods vary significantly, such as forging, owing to their difficult-to-cut property and the uncontrollable vibration generated during machining. A method to minimize the vibration generated during machining by applying advanced tools and controlling the sequence of machining processes, which can improve the machinability and precision of titanium alloy-forged low-angle components, is proposed herein. Using the proposed tool and based on a process order experiment, the efficiency of the machining process is verified by measuring the dimensional deformation of the low-angle component.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.1
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• pp.17-23
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• 2017

This study is about the development and revision of a blower design for a ventilation system. In this study, to describe the flow in the 4000CMM grade blower, 3-dimensional steady-state turbulence was assumed to govern the flow equation. The flow field with velocity distribution according to the elbow duct of the ventilation system is also compared. Finally, vibration was observed in the blower at the installation to ventilation system. The cause was due to a problem in the manufacturing process of the airfoil type impeller.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.5
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• pp.27-34
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• 2021

This study analyzes machining characteristics and presents optimal cutting conditions by measuring the surface roughness, dimensional accuracy, and dimension straightness based on the feed rate after processing the inner diameter hall of SCM415 steel using an automatic CNC(Computerized Numerical Control) lathe. The testing material was cut using an 11.8 mm-diameter Chamdrill after mounting the 32 mm-diameter round bar on an automatic CNC lathe. The cut depth was set at 3 mm, and the cutting speed was fixed at 1500 rpm. The surface roughness, dimensional accuracy, and dimension straightness of 15 testings were measured by changing the feed rate to 0.05, 0.1, and 0.15 mm/rev, respectively. It was difficult to process more than 15 tests during the maching due to noise or break. Additionally, the optimum cutting of SCM415 steel showed excellent surface roughness in the 10^th and 11^th of testing at cutting speed and feed speed of 1500 rpm and 0.05 mm/rev, respectively. The dimensional accuracy was measured in three dimensions after drilling, which showed good results with an average range of 0.0138-0.0208 mm. Moreover, the lower the feed speed, the higher the accuracy. Additionally, the measurement results of the dimensional straightness showed that the straightness is the straightness was the best at the 1^th and 2^th cutting regardless of the feed speed.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.760-765
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• 2001

A new rapid prototyping process, as a transfer type of Variable Lamination Manufacturing by using expandable polystyrene foam (VLM-ST), has been developed to reduce building time, apparatus cost including the introduction and the maintenance and additional post-processing. The objective of this study is to propose a VLM-ST process and to develop an apparatus for implementation of the process. Design criteria of the apparatus were defined and the techniques were proposed to satisfy the design criterion. In order to examine the efficiency and applicability of the developed process, various three-dimensional shapes, such as a world-cup logo, a knob shape and a character, Son-o-kong, were fabricated on the apparatus in which unit shape layer (USL) was generated to build up each layer.

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.4
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• pp.483-489
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• 2019

With development of digital dentistry, the 3-dimensional (3D) manufacturing industry using computer-aided design and computer-aided manufacturing (CAD/CAM) has grown dramatically in recent years. Denture fabrication using digital method is also increasing due to the recent development of digital technology in dentistry. The 3D manufacturing process can be categorized into 2 types: subtractive manufacturing (SM) and additive manufacturing (AM). SM, such as milling is based on cutting away from a solid block of materal. AM, such as 3D printing, is based on adding the material layer by layer. AM enables the fabrication of complex structures that are difficult to mill. In this case, additive manufacturing method was applied to the fabrication of the resin-based complete denture to a 80 year-old patient. During the follow-up periods, the denture using digital method has provided satisfactory results esthetically and functionally.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.10
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• pp.104-109
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• 2019

Reverse engineering techniques using 3D scanners and 3D printing technologies are being used in various industries. In this paper, the three-dimensional model is designed for automotive hub parts through 3D scanning and reverse engineering, and the design of hub parts is intended to be printed on FDM-style 3D printers to measure and analyze the dimensions of hub parts designed for reverse design and 3D printed hub parts. Experimental result have shown that the dimensions of 3D printed hub parts are small compared to those of the reverse-engineered dimensions, which are due to the shrinkage of filament materials in 3D printing.

• Journal of Technologic Dentistry
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• v.39 no.3
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• pp.137-143
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• 2017

Purpose: The purpose of this study is to analyze the fitness of heat - pressed ceramic laminate veneers fabricated using the additive manufacturing. Methods: Impression was replicated by using light body silicone and heavy body silicone on the custom tray, and it was fabricated using Type IV Stone. The test specimens were prepared by using a dental scanner, a laminating veneer using a dental design program, and a specimen with a 3D printer. The control specimens were prepared by the lost wax technique and heat - pressed to fabricate the specimens. The data of the specimens were measured by the RMS value of the internal fitness a using a 3-dimensional measurement program. Results: The Stereolithography laminate veneer group was measured at $78.10(4.09){\mu}m$ and the LWV group was measured at $31.50(5.10){\mu}m$. There is a significant difference between the two groups (p<0.001) Conclusion : Evaluation of fitness laminate veneers was fabricated by additive manufacturing showed the difference statistically significantly and clinically acceptable result.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1994.06a
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• pp.163-172
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• 1994

The Aerospace and automobile industries have need to avoid sheet-metal forming problem such as incorrect springback after forming and trimming process, excessive thinning/tearing, wrinking/perkering. It is common practice to use costly trial-and-error experimental methods to develop tooling and manufacturing process parameters. Experimentation should be complemented with computer simulation to reduce cost and leadtime in manufacturing and to influence the design of components. In this study, firstly we solved the springback problem after drawing and trimming process of KFP(F100-229) engine airsealing bearing support part(53H00) forming and studied on the effect of several process parameters on the gap between the formed blank and punch shape using the implicit F.E.M code(ABAQUS). Secondly by the three dimensional dynamic analysis using the explicit. F. E. M code (LS-DYNA3D), we studied on the effect of several process parameters which can be used for avoid tearing and wrinking during the drawing process.

• IE interfaces
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• v.16 no.2
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• pp.258-267
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• 2003

Recently, virtual reality technologies have been rapidly developed and realtime virtual simulation methods have been extensively employed for several application areas such as game, sports, manufacturing, military, and so on. A 3D database in realtime virtual simulation plays a key role because it makes users feel reality in virtual space. In a application view of 3D database, a systematic construction approach is required to reduce its construction time and increase its quality. However, many researches have been mostly focused on realtime graphic issues and its key technologies. In virtual simulation of transportation equipments, this paper proposes a systematic construction process of 3D database consisting of four stages as follows: 1) determine the activity space of a equipment, 2) collect data related to 3D database construction, 3) make a 3-dimensional modeling strategy, and 4) generate and evaluate a 3D model. This paper also introduces a new procedure of 3D environment modeling, which summarizes and expands our modeling experiences, to be used as a modeling guide.