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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society for Precision Engineering
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Journal DOI :
Korean Society of Precision Engineering
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Volume & Issues
Volume 32, Issue 12 - Dec 2015
Volume 32, Issue 11 - Nov 2015
Volume 32, Issue 10 - Oct 2015
Volume 32, Issue 9 - Sep 2015
Volume 32, Issue 8 - Aug 2015
Volume 32, Issue 7 - Jul 2015
Volume 32, Issue 6 - Jun 2015
Volume 32, Issue 5 - May 2015
Volume 32, Issue 4 - Apr 2015
Volume 32, Issue 3 - Mar 2015
Volume 32, Issue 2 - Feb 2015
Volume 32, Issue 1 - Jan 2015
Selecting the target year
Study for Applicability of Polymer and Polymer Coated Metal Materials within PBF System
Kim, Dong Soo ; Bae, Sungwoo ;
Journal of the Korean Society for Precision Engineering, volume 32, issue 9, 2015, Pages 765~771
DOI : 10.7736/KSPE.2015.32.9.765
In an Additive Manufacturing (AM) system emplying the Powder Bed Fusion (PBF) system, polyamide-12 powder is currently recognized as the general material used. The Polyamide-12 powder's properties include an average particle size of 58
, a density of 0.59 g/cm3, and melting point of
, and can also be to used coat materials for metal powder. For this reason, the sintering process is similar to the polymer powder and polymer coated metal powder process, except during the post-process. The polyamide-12 powder has some disadvantages such as its high cost and the fact that it can only be used for the provided equipment from the maker. Therefore, this study aims to perform the applicability of new material, polymer and polymer coated metal, to the PBF system.
Study on the Development and Sintering Process Characteristics of Powder Bed Fusion System
An, Young Jin ; Bae, Sungwoo ; Kim, Dong Soo ; Kim, Jae Yeol ;
Journal of the Korean Society for Precision Engineering, volume 32, issue 9, 2015, Pages 773~779
DOI : 10.7736/KSPE.2015.32.9.773
The laser Powder Bed Fusion (PBF) system is currently recognized as a leading process. Due to the various materials employed such as thermoplastic, metal and ceramic composite powder, the application's use extends to machinery, automobiles, and medical devices. The PBF system's surface quality of prototypes and processing time are significantly affected by several parameters such as laser power, laser beam size, heat temperature and laminate thickness. In order to develop a more elaborate and rapid system, this study developed a new PBF system and sintering process. It contains a 3-axis dynamic focusing scanner system that maintains a uniform laser beam size throughout the system unlike the
lens. In this study, experiments were performed to evaluate the effects of various laser scanning parameters and fabricating parameters on the fusion process, in addition to fabricating various 3D objects using a PA-12 starting material.
Development of Multi Piezo Ink-Jet Printing System Using Arbitrarily Waveform Generator
Kim, Jung Su ; Kim, Dong Soo ;
Journal of the Korean Society for Precision Engineering, volume 32, issue 9, 2015, Pages 781~786
DOI : 10.7736/KSPE.2015.32.9.781
Recently, studies of 3D printing methods have been working in various applications. For example, the powder base method laminates the prints by using a binding or laser sintering method. However, the draw back of this method is that the post process is time consuming and does not allow for parts to be rapidly manufactured. The binding method requires the post process while the time required for the post process is longer than the manufacturing time. This paper proposes a UV curing binding method with an integrated piezo printing head system. The optimization of an arbitrary waveform generation for the control of a UV curable resin droplet was researched, in addition to developed optimized UV curing processes in multi nozzle ink jet heads.
Evaluation and Development of Multi Thermal Bubble Ink Jet 3D Printing System
Shin, Mun Gwan ; Bae, Sung Woo ; Kim, Jung Su ;
Journal of the Korean Society for Precision Engineering, volume 32, issue 9, 2015, Pages 787~792
DOI : 10.7736/KSPE.2015.32.9.787
Recently, 3D printing technology is a hot issue in various industrial fields. According to the user's application, it allows for the free form fabrication method to be utilized in a wide range. The powder based fusion technique is one of the 3D printing methods. When using this method it is possible to apply the various binder jetting techniques such as piezo, thermal bubble jet, dispenser and so on. In this paper, a multi thermal bubble ink jet was integrated for jetting of powder binding material and developing a power fused 3D printing system. For high quality 3D printing parts, it needs an analysis and evaluation of the behavior of the thermal bubble ink jet head. In the experiment, a correlation between jetting binder quantity and layer thickness of powder was investigated, and a 3D part model was fabricated, which was used by measuring the scale factor.
Experimental Study on the Size Effect and Formability of Sheet Materials in Microscale Deep Drawing Process
Nam, Jung Soo ; Lee, Sang Won ; Kim, Hong Seok ;
Journal of the Korean Society for Precision Engineering, volume 32, issue 9, 2015, Pages 793~798
DOI : 10.7736/KSPE.2015.32.9.793
This study investigates the effects of the size of copper sheets on the plastic deformation behavior in a microscale deep drawing process. Tensile tests are conducted on the copper sheets to study the flow stress of the materials with different grain sizes before carrying out the microscale deep drawing experiments. After the tensile tests, a novel desktop-sized microscale deep drawing system is used to perform the microscale deep drawing process. A series of microscale deep drawing experiments are subsequently performed, and the experimental results indicate that an increase in the grain size results in the reduction of the deformation load of the copper sheets due to the effects of the surface grain. The results also show that the blank holder gap improves both the formability of copper sheets and the material flow.
3D Accuracy Enhancement of BGA Shiny Round Ball Using Optical Triangulation Method
Joo, Byeong Gwon ; Cho, Taik Dong ;
Journal of the Korean Society for Precision Engineering, volume 32, issue 9, 2015, Pages 799~805
DOI : 10.7736/KSPE.2015.32.9.799
The further development of information, communication and digital media technologies requires the use of advanced, miniaturized semiconductor chips that operate at a high frequency. Die bonding and wire bonding methods for semiconductor packaging have been replaced by direct attachment to the substrate after forming a bump on the chip. However, the height of the bump or ball is an important factor for defects during assembly. This paper proposes an algorithm to measure the height of the bumps or balls in semiconductor packaging with greater accuracy. The performance of the proposed algorithm is experimentally validated. Non-contact 3D measurements of a shiny round ball is quite difficult, and it is not easy to obtain accurate data. This paper thus proposes an optical method and technique to improve the measurement accuracy.
Study on the Out-of-Plane Deformation Measurement Condition through Comparison Photosensitivity
Kim, Hyun Ho ; Kang, Chan Geun ; Lee, Hyun Jun ; Jung, Hyun Chul ; Kim, Kyeong Suk ; Hong, Chung Ki ;
Journal of the Korean Society for Precision Engineering, volume 32, issue 9, 2015, Pages 807~813
DOI : 10.7736/KSPE.2015.32.9.807
In the present study, an interferometer system, which integrates the laser sensitivity control technique based on the theory of electronic speckle pattern interferometry, one of non-contact non-destructive analysis methods, was developed. This interferometry system receives an image from CCD cameras for each reference and object, and compares the photosensitivity of the object and reference images from imagification. For the purpose of this study, the photosensitivity of object and reference light is measured with power meters, and the amount of light was controlled with an ND filter with a reference light port matching photosensitivity. Using the plate specimen as the object, 0.6, 0.9, 1.2, and
of out-plane deformation was made, and images were compared according to the difference in photosensitivity. After analysis, larger object deformations showed larger numbers of stripe patterns. Images became clearer and data error was reduced when the photosensitivity of object and reference light matched.
Approximate Multi-Objective Optimization of Gap Size of PWR Annular Nuclear Fuels
Doh, Jaehyeok ; Kwon, Young Doo ; Lee, Jongsoo ;
Journal of the Korean Society for Precision Engineering, volume 32, issue 9, 2015, Pages 815~824
DOI : 10.7736/KSPE.2015.32.9.815
In this study, we conducted the approximate multi-objective optimization of gap sizes of pressurized-water reactor (PWR) annular fuels. To determine the contacting tendency of the inner-outer gaps between the annular fuel pellets and cladding, thermoelastic-plastic-creep (TEPC)analysis of PWR annular fuels was performed, using in-house FE code. For the efficient heat transfer at certain levels of stress, we investigated the tensile, compressive hoop stress and temperature, and optimized the gap sizes using the non-dominant sorting genetic algorithm (NSGA-II). For this, response surface models of objective and constraint functions were generated, using central composite (CCD) and D-optimal design. The accuracy of approximate models was evaluated through
value. The obtained optimal solutions by NSGA-II were verified through the TEPC analysis, and we compared the obtained optimum solutions and generated errors from the CCD and D-optimal design. We observed that optimum solutions differ, according to design of experiments (DOE) method.
Muscular Activity Analysis in Lower Limbs from Motion and Visual Information of Luge Simulator based Virtual Reality
Kang, Seung Rok ; Kim, Ui Ryung ; Kim, Kyung ; Bong, Hyuk ; Kwon, Tae Kyu ;
Journal of the Korean Society for Precision Engineering, volume 32, issue 9, 2015, Pages 825~831
DOI : 10.7736/KSPE.2015.32.9.825
In this paper, capture motion and visual information from a virtual reality luge simulator to analyze muscular activity in the lower limbs. The Luge Simulator consists of a motion platform with a pneumatic module for weight distribution. We recruited luge athletes and healthy subjects and made real-time surface EMG measurements to estimate the muscular activity in the lower limbs according to the motion protocol of a simulator, and a test was conducted for each subject. The results indicated that the rectus femoris had the highest muscular activity according to the level of the slope and velocity of the luge. The soleus muscle showed a high level of activity during a turn in the luge according to the direction. We found that the development of a virtual reality sports simulator based on physical reaction results could bring positive effects to optimize reality and human cenesthesia.
Using CAD-Converted Bitmap Images for Inkjet Printing
Kim, Hyung Seok ; Kwon, Kye-Si ;
Journal of the Korean Society for Precision Engineering, volume 32, issue 9, 2015, Pages 833~840
DOI : 10.7736/KSPE.2015.32.9.833
Inkjet technology is one of the commonly used technologies in the printed-electronics field. The primary issue regarding the usage of inkjet technology as a printed-electronics tool is the printing resolution; therefore, to print complicated patterns of precise dimensions, we developed software that can convert a CAD file into a bitmap image. Moreover, as a bitmap image is not comprised of physical dimensions, its resolution needs to be defined in terms of pixel distance to print a rasterized bitmap image. In this study, we investigated the effects of pixel distance and dot size on printing resolution; based on the experiment results, we concluded that the printed dot size should be used to determine the optimal pixel distance. Lastly, we also propose inkjet printing procedures for bitmap images.