• 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 Korea Society for Energy Engineering kosee Conference
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• 1999.05a
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• pp.145-150
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• 1999

As proven petroleum reserves decline through continued production. exploration for new oil and gas resources will extend into environments which present significant economic risks arid technical hurdles. Since safety is one of the biggest concerns in drilling operations. the oil industry routinely trains its personnel in areas which are critical for safe and economical drilling procedures. One of these major areas is well control. A kick is defined as an unscheduled flow of formation fluids into a wellhole. A kick occurs whenever the resultant wellbore pressure is less than the formation pressure in an exposed zone capable of producing kick fluids. The typical causes of reduced wellbore pressure are insufficient mud weight. inadequate fluid level in the hole, and swabbing.(omitted)

• Journal of the Korean Society for Precision Engineering
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• v.3 no.2
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• pp.91-101
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• 1986

This paper deals with the effect of static and dynamic cuttig force and the behaviour of drill life in drilling process. The experiments are performed with cemented carbide drills and high speed steel drills of 10mm in diameter and in an annealed SM45C. The conclusions are as follows (1) Dynamic cutting force is varied with the dept of hole. (2) Dynamic cutting forces of torque and thrust are increase with the increase in feed and cutting speed. (3) Chipping influence the dynamic cutting force of thrust than torque, and in the case of thrust, the amplitude is 3-7 times large than ordinary cutting state. (4) Prediction of drill life can be obtained from more easily the amplitude of static cutting force than that of dynamic cutting force.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.12
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• pp.1984-1991
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• 1997

Recently burr technology is rising in the fields of the precision manufacturing and the high quality machining, deburring has treated as a difficult problem on going to the high efficiency, automation in the FMS. Removal of burr with various shapes, dimensions and properties couldn't be standardized and has depended on manual treatment. Especially, deburring for cross hole inside owing to passing through out perpendicular to a main hole is more difficult, the electrochemical method is proper as its solution at practical aspects. Burr elimination in the cross hole drilling of governor shaft used in the automobile engine so far has been worked by a manual post-processing by a skillful worker, which becomes a factor of productivity-down and cost-up so that improvement of machining process is needed. Therefore, for the high efficiency and automation of internal deburring in the cross hole, development of electrochemical deburring technology is needed. So, the new process in the burr treatment is supposed. In this study, characteristics of electrochemical deburring through experiments were identified and factors such as electrolytic gap and electorlytic fluid contributed to removal burr height were analyzed. Also, deburring efficiency and electrolytic performance for cross hole were examined according to electrolytic current and electrochemical deburring condition corresponding to acquired edge quality was found out.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.729-730
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• 2010

• Journal of the Korean Society for Nondestructive Testing
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• v.9 no.2
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• pp.61-66
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• 1989

Welding residual stress was measured by ultrasonic birefringence technique. Acoustoelastic constant was taken by averaging the values in the literature. The initial birefringence from prefered orientation of grains was measured. The EMAT transducers were used to remove couplant effect. The results show that the distribution and magnitude of welding residual stress from ultrasonic measurement are in good agreements with those from semi destructive hole drilling measurement.

• Proceedings of the KWS Conference
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• 1994.05a
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• pp.157-160
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• 1994

Characteristics of laterally bonded tri-metal sheets (stainless steel/Invar/stainless steel) fabricated by laser beam welding are compared to those of samples by Imphy and Hitachi Co-operations. Residual stess of tri-metal is calculated by using of the hole-drilling stain gauge method. The aging effect of stainless steel strip on welding is also discussed. In addition to, a numerical approach for laser beam welding is tried. Finally, laser beam welding system of tri-metal can be designed on th basis of experimental and theoretical results.

• Journal of the Korean Society of Safety
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• v.22 no.1 s.79
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• pp.19-23
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• 2007

The aim of this study was to determine residual stresses in thermal barrier coatings(TBCs) by isothermal heating. Specimens were heated at the range of $1000{\sim}1600^{\circ}C$. A finite element method was used to determine the residual stresses. Finite element coupled heat transfer and elastic-plastic thermal stress analysis using a general purpose commercial FEM software ABAQUS. I obtained the stresses were not affected below the temperature of $1400^{\circ}C$ but affected over that of temperature.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.185-186
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• 2011

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1287-1288
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• 2011