• Journal of Electrical Engineering and Technology
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• v.12 no.6
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• pp.2256-2261
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• 2017

Carbon nanotube (CNT) and alumina ($Al_2O_3$) are synthesized into hybrid composites, and an advanced electrical discharge machining (EDM) system is developed for the machining of hard and conductive materials. CNT nanoparticles are mixed with $Al_2O_3$ powder and the $Al_2O_3$/CNT slurry is sintered by spark plasma. The hardness and the electrical conductivity of the $Al_2O_3$/CNT hybrid composite were investigated. The electrical discharge is controlled by a capacitive ballast circuit. The capacitive ballast circuit is applied to the tungsten carbide and the $Al_2O_3$/CNT hybrid composite. The voltage-current waveforms and scanning electron microscope (SEM) images were measured to analyze the characteristics of the boring process. The developed EDM process can manufacture the ceramic based hybrid composites, thereby expecting the variety of applications.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.3
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• pp.55-61
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• 2000

In this paper we have discussed on the characteristics and modeling of machined geometry which was established for the case of round shape machining also the effects of externally machined profile are analyzed and its modeling realia-bility was verified by the experiments of roundness testing especially in lathe operation. In this study we established a harmonic geometric model with the parameter harmonic function. In general we can calculate the theoretical roundness profile with an arbitrary multilobe parameter. But in real experiments only 2-5 lobe profile was frequently measured, The most frequently measured ones are 3 and 5 lobe profile in experiments. With these results we can predict that these results may be applied to round shape machining such as turning drilling boring ball screw and cylindrical grinding operation in bearing and shaft making operation with the same method. in this study simulation and experimental work were performed to show the profile behaviors. we can apply these new modeling methods in real process for the predic-tion of part profile behaviors machined such as in round shape machining operation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1991.11a
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• pp.121-125
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• 1991

In order to minimize fixing error of workpieces, prismatic and cylindrical types. Modification Rule by Indexing Table and Modification Rule by NC Program are developed for machining centers by using touch trigger probes. The Modification Rule by Indexing Table means the alignment of workpiece to NC program through degree of freedoms of indexing table. The Modification Rule by NC Program is the alignment of NC program to workpiece set-up condition via the generation of NC program. A postprocessing module is also developed for generating NC-part Program (User Macro) to compensate for Machining errors in end milling and boring processes. Developed methods are verified by experiments.

• Journal of Advanced Marine Engineering and Technology
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• v.18 no.2
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• pp.64-74
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• 1994

The gundrill is capable of machining for having large length to diameter ratio in single pass. The techniques of gundrill and gun boring began developing in the late 18th century with the need for more accurate bores in rifle, cannon, machinery part and marine part etc. The main feature of the gun drilling provides a stabilizing cutting force resultant necessary for self guidance of the drill head. A study of the accuracy and surface finish of holes produced would reveal quite useful information regarding the process. The thesis deals with the experimental results obtained during gun drilling on marine part materials for different machining conditions.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1996.03a
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• pp.18-23
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• 1996

The Job of Milling in the Local Skill Contest in 1996 was to assemble parts into a complete whole of the parts number 1, 3, 4 worded by Milling Machine and the parts number 2 worked by Machining Center. In the parts of Milling Machine, the Job was to work 45$^{\circ}$angle working, T-slot, dovetail, the correct position drilling, rimming, boring, etc. In the Machining Center, there were the way of calculation of point of contact of 'R' contour curved line and lots of working elements. So, it was possible to work the parts and assemble them within the time limit only through the program to be made out in the way to shorten working hours.

• Journal of the Korean Society of Industry Convergence
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• v.22 no.6
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• pp.607-613
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• 2019

In this study, we investigate the effect of SNCM616 alloy steel, which is commonly used in industry, such as rotors and crank-shafts, on the surface roughness of CNC HBM with Ø25 mm, 8-blade reamer to objective is to analyze and present optimal cutting conditions. The higher the feedrate for the spindle speed, the rougher the surface roughness. The surface roughness was found to be better when the feed rate was lower. The resultant value of the most accurate surface roughness is Ra 0.756 ㎛, and the optimal cutting conditions are 25 rpm at spindle speed and 20 mm/min at transfer speed.

• Journal of Power System Engineering
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• v.2 no.2
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• pp.73-80
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• 1998

The identification of drilling joint dynamics which consists of drilling and structural dynamics and the on-line time series detection of malfunction process is substantial not only for the investigation of the static and dynamic characteristics but also for the analytic realization of diagnostic and control systems in drilling. Therefore, We have discussed on the comparative assessment of two recursive time series modeling algorithms that can represent the drilling operation and detect the abnormal geometric behaviors in precision roundshape machining such as turning, drilling and boring in precision diemaking. For this purpose, simulation and experimental work were performed to show the malfunctional behaviors for drilling operation. For this purpose, a new two recursive approach (Recursive Extended Instrument Variable Method : REIVM, Recursive Least Square Method : RLSM) may be adopted for the on-line system identification and monitoring of a malfunction behavior of drilling process, such as chipping, wear, chatter and hole lobe waviness.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.326-331
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• 1999

Grinding technology in morden industry society is focusing on research & development for grinding stone and machining parts for the purpose of high accuracy and high efficiency of products. But, in order to equip the high technology and high accuracy of micro stone which is one of grinding stone, hardly and continuous effort on R&D is required.In this study, honing processing work of 2-cycle engine cylinder for motorcycle which has open hole is practiced so as to clear how borning that is prior step of honing and hone stone make an influence on accuracy of honing. As the result of analyzing the results of experiments, we came to conclusion that we can secure good conditions of honing by controlling and keeping appropriate cycle-time in the stage of boring of prior step of honing.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.2
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• pp.98-104
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• 2012

In this paper, precision processing is carried out for the pre hardened steel(HRC 54), which is one of injection mould materials. Processing characteristics are estimated according to the number of tool cutting blade and roundness is observed by the 3-Dimensional measuring machine. The surface roughness affected by the wire electric discharge machining are measured. Cutting component force of STAVOX is the highest in condition of 2F processing because load per a blade of cutting tool is high. Especially, the difference in Fz is over 20N by cutting load. The slower spindle rotation speed and tool feed rate are, the better cutting component force is. The roundness of hole processed in condition of 4F is good because feed rate is able to be fast. When rotation speed is increased, the surface roughness is decreased. The surface roughness acquired in condition of 2F processing is higher about 50% than 4F processing.

• International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
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• v.3 no.1
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• pp.40-48
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• 2000

The term "deep holes" is used to describe the machining of holes with a relatively large length to diameter ratio. The main feature of BTA deep hole drilling is the stabilization of cutting force necessary for the self guidance of the drill head. An additional feature is the cutting tool edges that are unsymmetrically placed on the drill head. There is an increasing necessity to predict the hole geometry and other dynamic stability behavior of deep hole drilling guidance. In this study, the effects of BTA deep hole drilling conditions on the hole profile machined piece are analyzed using domain analysis technique. The profile of deep hole drilled work piece is related to cutting speed, feed rate, chip flow, tool wear, and so on. This study deals with the experimental results obtained during the BTA drilling on SM45C, SM55C carbon steels and SCM440 steels under various cutting conditions, and these results are compared with analytical evaluations.aluations.