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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society for Precision Engineering
Journal Basic Information
Journal DOI :
Korean Society of Precision Engineering
Editor in Chief :
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
A Study on the Clamping Improvement of Precision Screws according to the Materials and Thread Changes
Hwang, Woo Chae ; Ra, Seung Woo ;
Journal of the Korean Society for Precision Engineering, volume 32, issue 6, 2015, Pages 503~507
DOI : 10.7736/KSPE.2015.32.6.503
In this study, we compare the performance of the screw through the Clamping force of the test materials to change shape and structure, one of the ways to maintain and improve the engaging force to cope with the miniaturization of the fastener threads are further thinner and lighter precision way that can improve the fastening force of the screw results were as follows. The clamping force according to the materials was
in SUS XM7 and SWCH18A was
. This result was to be found to average 13.5% high in the Clamping force of SUS XM7 materials. In the case of the clamping force of the screw thread shape change, the clamping force of symmetrical and asymmetrical thread was
. The clamping force of the asymmetrical thread showed an average high of 11.6%.
Finite Element Analysis for Improvement of Folding Defects in the Forging Process of Subminiature Screws
Lee, Ji Eun ; Kim, Jong Bong ; Park, Keun ;
Journal of the Korean Society for Precision Engineering, volume 32, issue 6, 2015, Pages 509~515
DOI : 10.7736/KSPE.2015.32.6.509
Recent trends to reduce the size of mobile electronics products have driven miniaturization of various components, including screw parts for assembling components. Considering that the size reduction of screws may degenerate their joining capabilities, the size reduction should not be limited to the thread region but should be extended to its head region. The screw head is usually manufactured by forging in which a profiled punch presses a billet so that plastic deformation occurs to form the desired shape. In this study, finite element (FE) analysis was performed to simulate the forging process of a subminiature screw; a screw head of 1.7 mm diameter is formed out of a 0.82 mm diameter billet. The FE analysis result indicates that this severe forging condition leads to a generation of folding defects. FE analyses were further performed to find appropriate punch design parameters that minimize the amount of folding defects.
On Clamping Force Characteristics in M1.4 Subminiature Screw for CFRP Stacking Angles
Kim, Jung Ho ; Ra, Seung Woo ; Kim, Hee Seong ; Kim, Ji Hoon ;
Journal of the Korean Society for Precision Engineering, volume 32, issue 6, 2015, Pages 517~521
DOI : 10.7736/KSPE.2015.32.6.517
Recent development of core techniques the IT electronics industry can condense into lightweight and slimmer. In this circumstance, researches for the lightweight materials and subminiature screw have been attracted. In this study, the CFRP was produced by stacking angle to obtain the tensile properties. And Comparing the coated screws and non-coated screws on the specimen, and evaluating the adequacy for the application of CFRP using the result. So The clamping force measured by comparison evaluation. Low screw reverse and Superior torque value at each stacking angle were found the optimum conditions, when Subminiature Screw is applied on smart devices. Both tensile strength and stiffness of
is the highest. Followed by
is the highest. The largest clamping torque is
When Subminiature Screw is applied coating and non-coating to prevent loosening. Based on the above, Subminiature Screw should be applied in smart devices, because
meet both tensile properties and clamping force.
Thread Shape Design Using Joining and Release Analysis of Bolts
Jeong, Jin Hwan ; Lee, Hyun-Kyu ; Kim, Jong-Bong ; Park, Keun ;
Journal of the Korean Society for Precision Engineering, volume 32, issue 6, 2015, Pages 523~528
DOI : 10.7736/KSPE.2015.32.6.523
As the sizes of mobile phones and watch phones decrease, the joining bolt for the products should also be decreased to a miniature size. However, the miniature-sized bolt has to support sufficient joining and anti-releasing torque to keep the product fastened. In this study, the thread shapes are designed to improve anti-releasing performance of bolts. Especially, when bolt materials is stronger than nut materials, the design of thread shapes is needed, like bolt for wood, to improve the fastening capability. Through the joining and releasing analyses of bolts, the thread shapes for SUS302 bolt and Mg alloy nut are newly designed. It was shown that the newly designed bolt has 20 % higher anti-releasing torque and 35% lower torque loosening slope compared to the standard bolt.
Application and Design of Eddy Current based on FEM for NDE Inspection of Surface Cracks with Micro Class in Vehicular Parts
Im, Kwang-Hee ; Lee, Seul-Ki ; Kim, Hak-Joon ; Song, Sing-Jin ; Woo, Yong-Deuk ; Na, Sung-Woo ; Hwang, Woo-Chae ; Lee, Hyung-Ho ;
Journal of the Korean Society for Precision Engineering, volume 32, issue 6, 2015, Pages 529~536
DOI : 10.7736/KSPE.2015.32.6.529
A defect could be generated in bolts for a use of oil filters for the manufacturing process and then may affect to the safety and quality in bolts. Also, fine defects may be imbedded in oil filter system. So it is very important that such defects be investigated and screened during the multiple manufacturing processes. Therefore, in order effectively to evaluate the fine defects, the FEM simulations were performed to make characterization in the crack detection of the bolts and the parameters such as number of turns of the coil, the coil size, applied frequency were calculated based on the simulation results. Simulations were carried out for the defect signal of eddy current probe. Exciter and receiver were utilized. In this paper, the FEM simulations were performed in both bobbin-type and pancake-type probe, both probes were optimized under Eddy current FEM simulations and the results of calculation were discussed.
Measurement of 3D Shape of Fastener using Camera and Slit Laser
Kim, Jin Woo ; Song, Tae Hun ; Ha, Jong Eun ;
Journal of the Korean Society for Precision Engineering, volume 32, issue 6, 2015, Pages 537~542
DOI : 10.7736/KSPE.2015.32.6.537
The measurement of 3D shape is important in inspecting the quality of product. In this paper, we present a 3D shape measurement system of fastener using a camera and a slit laser. Calibration structure with slits is used in the extrinsic calibration of the camera and laser. The pose of the camera and laser is computed under the same world coordinate system in the calibration structure. Reflection of laser light on the metal surface causes many difficulties in the robust detection of them on image. We overcome this difficulty by using color and dynamic programming. Motor stage is used to rotate the fastener to recover the whole 3D shape of the surface of it.
Dimension Measurement for Large-scale Moving Objects Using Stereo Camera with 2-DOF Mechanism
Cuong, Nguyen Huu ; Lee, Byung Ryong ;
Journal of the Korean Society for Precision Engineering, volume 32, issue 6, 2015, Pages 543~551
DOI : 10.7736/KSPE.2015.32.6.543
In this study, a novel method for dimension measurement of large-scale moving objects using stereo camera with 2-degree of freedom (2-DOF) mechanism is presented. The proposed method utilizes both the advantages of stereo vision technique and the enlarged visibility range of camera due to 2-DOF rotary mechanism in measuring large-scale moving objects. The measurement system employs a stereo camera combined with a 2-DOF rotary mechanism that allows capturing separate corners of the measured object. The measuring algorithm consists of two main stages. First, three-dimensional (3-D) positions of the corners of the measured object are determined based on stereo vision algorithms. Then, using the rotary angles of the 2-DOF mechanism the dimensions of the measured object are calculated via coordinate transformation. The proposed system can measure the dimensions of moving objects with relatively slow and steady speed. We showed that the proposed system guarantees high measuring accuracy with some experiments.
Control Strategy and Algorithm for Levitation of Over-actuated Passive Maglev Tray System
Ahn, Changsun ;
Journal of the Korean Society for Precision Engineering, volume 32, issue 6, 2015, Pages 553~562
DOI : 10.7736/KSPE.2015.32.6.553
This paper presents a strategy and an algorithm for levitation control of an over-actuated passive maglev tray system. The passive maglev tray system has more actuators than its degrees of freedom. The actuators of the system are switching when the tray travels longitudinally. Furthermore, the levitation forces of the actuators are non-homogeneous because the actuation devices are not in the moving platform. These characteristics make a limit in using conventional control approaches for levitation. For smooth actuator switching, the actuator force generation should be dependent on longitudinal positions of the tray. To enable constant pose tracking, this research introduces a control strategy and a control algorithm based on integral controllers on virtual variables. The states of the tray are estimated using a Kalman filter and fed to the proposed controller. The performances of the proposed control strategy and the algorithm are validated through tests.
Thermal-electromagnetic Coupled Analysis for Gear Heat Treatment using Simultaneous Duel Frequency
Yun, Dongwon ; Park, Heechang ; Ham, Sangyong ; Koo, Jeong-Hoi ;
Journal of the Korean Society for Precision Engineering, volume 32, issue 6, 2015, Pages 563~570
DOI : 10.7736/KSPE.2015.32.6.563
In this paper, Finite Element Analysis (FEA) for gear heat treatment using simultaneous dual frequency (SDF) induction heating is conducted. To do this, thermal-electromagnetic coupled FE model is built. A two dimensional FE model of gear and heater is introduced to reduce computation time. For more time-efficient analysis, harmonic analysis for electromagnetic model is adopted and transient analysis model, for heat transfer model. Through the coupled analysis, it can be found that the proposed FE model can solve for SDF induction heating of gear and heat treatment parameters can also be determined.
Influence of Parameter Setting in an Oil Cooler on the Temperature Characteristics of an Ultra-precision Hydrostatic Table
Khim, Gyungho ; Kim, Chang Ju ; Oh, Jeong Seok ; Park, Chun Hong ;
Journal of the Korean Society for Precision Engineering, volume 32, issue 6, 2015, Pages 571~576
DOI : 10.7736/KSPE.2015.32.6.571
Temperature characteristics of supply oil in an ultra-precision hydrostatic table are largely influenced by parameter setting in an oil cooler such as the location of reference sensor and cooling temperature. In this paper, influences of the parameter setting on the temperature variation in the hydrostatic table are experimentally analyzed to suggest the guidelines for practical application. In case of using temperature of inlet oil as a reference sensor in the oil cooler, temperature rise of the supply oil is smaller and thermal settling time is faster than that of using temperature of outlet oil as a reference sensor. The experimental results also show that temperatures of table, rail and return oil can be made almost same, and thermal settling time can be decreased by setting cooling temperature in the oil cooler to be lower than atmospheric temperature.
Experimental Study of Dynamic Behavior of a Water Droplet on Diverse Wrinkling Surfaces
Baek, Dae Hyeon ; Zhao, Zhijun ; Park, Sang-Hu ;
Journal of the Korean Society for Precision Engineering, volume 32, issue 6, 2015, Pages 577~585
DOI : 10.7736/KSPE.2015.32.6.577
We fabricated multi-scale such as macro-, micro-, and multi-scale wrinkles by using repetitive volume dividing (RVD) method and thermal curing process. Also wrinkle surface was modified with coating of a self-assembled monolayer (SAM). We measured the contact angle of each wrinkled surface, and observed the behavior of droplets on sloping surface. Through experimental study, we found out that the contact angle was much higher in case of multi-scale and SAM coated wrinkles. And micro-scale wrinkle showed a high contact angle comparing with that of macro-scale wrinkle. Dynamic behaviors of a water droplet like sliding velocity on diverse wrinkled surfaces were dependent on their static contact angles. These results showed that hydro-dynamic characteristics were changed depending on the wrinkle structure and the material forming the wrinkle. These dynamic characteristics can be utilized in bio-chip, microfluidics, and many others in order to control easily chemical reactivity.