• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.438-441
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• 2002

Today, it is concentrating on automation and these appearance of industrial robot has been dealing flexibly with this field. If it is drilling through these industrial robot, it will be a high efficiency of the productivity. Therefore, electric drill is setting on articulated robot with six degree of freedom and the 5 face is drilling as the type of articulated robot by a machine object setting. This study was carried out to get the possibility about drilling as analyzing with experimental frequency, original vibration of robot and appearance of vibration when it is practical drilling.

• International Journal of Precision Engineering and Manufacturing
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• v.2 no.1
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• pp.11-17
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• 2001

In drilling of composite laminates, it is important to minimize of reduce occurrences of delaminations. In particular, a peel -up delamination at entrance and push-up delamination at exit are common. Deleaminations may by avoided by regulating the drill thrust force can be controlled by adjusting the feedrate of the drill. Dynamics involved in drilling of composite laminates is time varying and nonlinear. In this paper, a fuzzy logic model and control strategy are proposed. Simulation results show that the fuzzy model can describe the nonlinear time-varying process well. The fuzzy controller realizes a fast rise time and a little overshoot of drilling force.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1191-1198
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• 2005

To designer and builder because drilling log, last accomplishment of boring, is made by subsurface expbration of site person in charge base information intermediate delivered by unified style as is concise be. However, make and is using drilling log that is dissimilar in each engine without style or creation standard unified in the case of domestic. Civil engineers lose an opportunity that can get more informations thereby or problem of inappropriate design, construction often happens. In this study, analyzed drilling log style examination of inside and outside of the country and merits and demerits to solve problem of these design and construction. And study improvement item on recording contents and suggested consistent drilling log standard illustration plan.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.2
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• pp.10-17
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• 2001

Drilling is one of the most important operations performed in the machining industry. And the material of the workpiece has a profound effect on the tool life, the surface finish produced and the overall economy of the process. Hot-rolled high strength steels have been used for automobile structural material, owing to high hardness and machinability of the material. However, in the drilling of hot-rolled high strength steels, the current knowledge of tool wear and machinability are insuf-ficient. There, it is desirable to monitor drill wear status and hole quality changes during the hole drilling process. Accordingly, this paper deals with the cutting characteristics of the hot-rolled high strength steels using common HSS drill. The performance variables include the drilling thrust, torque and drill wear data obtained from drilling experiments con-ducted on the workpiece. Also drill were is measured by acoustic emission system and computer vision system.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.3
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• pp.90-95
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• 2000

Today fiber composite materials are routinely used in such wide applications as ships automobiles aircraft space vehi-cles containers sporting goods and appliances. The current knowledge of machining glass fiber reinforced polyester com-posites unfortunately is inadequate for its optimum utilization in many applications. Therefore This paper deals with drilling characteristic of glass fiber reinforced polyester composites. In the drilling of glass fiber reinforced polyester the quality of the cut surfaces is strongly dependent on the drilling parameters. drilling tests were carried out on glass fiber reinforced polyester using standard HSS tools. The material containing random chopped strand fibers and woven roving was fabricated by hand lay-up The entrance and exit surface of the holes was examined. The cutting force was also mea-sured to analyze the drilling characteristics,.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1998.10a
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• pp.84-89
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• 1998

BTA drilling among the deep hole drilling is using for the improvement of productivity and the high-efficient working. As the deep hole drilling with BTA drill is satisfied with the required quality by one-pass processing, more deeper hole depth, the accuracy of materials is affected by bending vibration and cutting speed. This paper is studied that the shapes of material (surface roughness, roundness) is affected by cutting condition compared actual roundness with lobe shape with modeling of computer through the experiments in the BTA drilling system with BTA drill.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.886-889
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• 2000

This paper describes the machining characteristics of the MoSi$_2$-based composites by electric discharge drilling with various tubular electrodes. MoSi$_2$-based composites has been developed in new materials for jet engine of supersonic-speed airplanes and gas turbine for high- temperature generator. By combining a nonconducting ceramics with more conducting ceramic it was possible to raise the electrical conductivity. In drilling by EDM, the dielectric flushed down the interior of the rotating tube electrode, in order to facilitate the removal of machining debris from the hole. Various metal-coated tubular electrodes of which core are copper and brass are used to know the effect of coating material on machinability of ED drilling.

• Korean Journal of Animal Reproduction
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• v.22 no.2
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• pp.163-169
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• 1998

본 실험은 체외 생산된 소 배반포기배에 대한 laser drilling 처리가 배의 부화율에 미치는 영향을 조사하고자 실시하였다. 그 결과는 다음과 같다. 소 수정란의 체외 발달율을 조사하였던 바, 82.3%의 난할율( 2-세포기)과 체외수정 후 배양 7일째에 32.6%의 배반포 발달율을 나타내었다. 이렇게 생산된 배반포기배에 laser drilling 효과를 조사하였던 바, 처리 후 24시간째의 부화진행율(90.0%)은 대조군(44.4%)보다 유의하게 높게 나타났다(p<0.0001). 또한, 처리 후 48시간째의 부화율(68.0%)도 대조군(33.3%)보다 유의하게 높게 나타났다. 이러한 결과는 laser drilling이 체외 생산된 소 배반포기배의 부화진행율과 부화율을 유의하게 증가시킬 수 있다는 것을 알 수 있었다(p<0.001).

• Journal of Ocean Engineering and Technology
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• v.2 no.2
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• pp.27-36
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• 1988

For the purposes of drilling oil field and extracting oil deep water in more rough weather, the size of drilling rigs must be estimated. In this paper, the three dimensional source distribution method is used and we assume 10 deg. heeling and trimming condition of the drilling rig(SR-192). Also, the effects of the hydrodynamic forces which include the drift forces for field method, and the motion responses are studied with changing the incident wave direction in the assumed inclining condition. The theory and numerical codes used in this thesis appeared to be very useful for the preliminary design of drilling rigs.

• Journal of the Korean Society of Safety
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• v.16 no.4
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• pp.47-51
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• 2001

The carbon fiber reinforced plastics(CFRP) have been widely used in aircraft and spacecraft structures as well as sports goods because it has high specific strength, high specific stiffness and low coefficient of thermal expansion. Machining of CFRP poses problems not frequently seen for metals due to the nonhomogeneity, anisotropy, and abrasive characteristics of CFRP. Delamination is a common problem faced while drilling holes in CFRP using conventional drilling. Therefore, AE characteristics related to drilling damage process of unidirectional and [0/90/]s crossply laminate composite was studied. Also drilling damage like the delamination was observed by video camera in real time monitoring technique. From the results, we basically found the relationships between the delamination from drilling and AE characteristics for CFRP composites.