• Journal of the Korean Society for Precision Engineering
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• v.17 no.11
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• pp.55-62
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• 2000

The poor machinability material such as austenite stainless steel(STS304) is emphasized on the wide use of HSSE for the tapping operation. The difficulty can be entirely to tapping torque due to chip formation through the hole of tap. The object of this study is to investigate tap geometry affecting the tapping torque from a practical point of view. The study shows that the optima tapping torque is affected by the tap geometry and cutting condition for STS304.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.05a
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• pp.636-637
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• 2010

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.44-45
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• 2011

• Journal of the Korean Society for Precision Engineering
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• v.19 no.11
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• pp.221-227
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• 2002

Tapping is a machining process that makes a female screw on parts to be assembly together. Recently, as the number of small and compact products increases the radius of tap as small as 1 mm is not unusual and more accurate tapping is needed. In complying with those needs, some high-speed tapping machines with synchronizing function have been developed. This paper describes the development of an ultra high-speed tapping machine up to 10,000rpm. The key factors in the tapping speed are the acceleration/deceleration and the synchronizing errors between spindle motor and fred motor. To minimize the acceleration/deceleration time, a low inertia spindle with a synchronous built-in servo motor was developed. To minimize the synchronizing errors, the tapping cycle algorithm was optimized on an open architecture CNC. The developed tapping machine has the acceleration/deceleration time of 0.13sec/10,000rpm for rigid tapping and the synchronizing error below 4.4%. The cycle time for tapping a female screw of M3 and depth 2 times diameter was 0.55sec.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.1
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• pp.22-28
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• 2010

To detect the damage in composite structure, nondestructive evaluation techniques are widely used. Tapping test is perhaps the most common technique used for the detection of damage in composite laminates. The method is accomplished by tapping the inspection area with light hammer-like device. The tapping test has the ability that indicates damages in a structure due to a localized change of stiffness. The change in vibration signature may be detected by measurement of the dynamic contact force during impact. In this study, it has been shown that the characteristics of impact force histories from a structure during tapping are changed by the presence of damage such as surface crack and delamination. And impact response analysis has been performed on composite rotor blade with crack to investigate the effect of damage.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.2
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• pp.105-111
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• 2012

High speed machining is the core technology that influences the performance of machine tools, and the high speed motor spindle is widely used for the high speed machine tools. The important problem in high speed spindle is to minimize the thermal effect by motor and bearing and frequency effect. This paper presents the thermal characteristic analysis and frequency experiment for a high speed spindle considering the flow rate of cooling oil. A high speed spindle is composed of angular contact ceramic ball bearings, high speed built-in motor, oil cooling jacket and so on. The thermal analyses of high speed spindle need to minimize the thermal effect and maximize the cooling effect and they are carried out under the various cooling conditions. Heat generations of the bearing and the high speed motor are estimated from the theoretical and experimental data. To find out the characteristic of vibration, the high speed spindle is excited in operational range. This result can be applied to the design and manufacture of a high speed tapping spindle.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.1
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• pp.31-35
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• 2003

Switch box is metal box and used for electric wire pipe in building. In manufacturing switch box, we need 5∼6 press machines, 5∼6 dies, 1 tapping machine. and 7∼8 operators. What matters is rise of manufacturing cost and operators' reluctance of working. To solve this problem, we modified the pre-existing die and developed handling mechanism, which leads to improve the manufacturing process. After the research and development, we could reduce the number of machines and workers needed in the process; 2 press machines, 2 dies, 1 tapping machine, and 1 operator. That means we can save labor and the number of operators needed, reduce manufacturing cost, and get the effect of import replacement.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.648-652
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• 1996

Grinding Center(GC)는 머시닝센터가 갖는 드릴링, 태핑 등의 절삭가공의 수행은 물론 주축의 고속화, 이송계의 고정밀화를 토대로 연삭숫돌의 절삭성 회복과 다듬질면의 거칠기를 확보하기 위한 기계로서 Dressing/Truing장치, 기상계측 장치, CNC기능을 구비하여 테이블과 공구간에 3차원의 상대운동을 시킴으로써 평면연삭, 내면연삭, 홈연삭, 캠연삭 등의 복잡한 형상의 연삭가공에 대해서도 공정을 집약화 할 수 있는 기계이다.(중략)

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.10a
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• pp.165-169
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• 2002

현재 개발 중에 있는 비파괴 검사법인 Tapping Sound Analysis 의 검증을 위해 실험으로 측정된 타격음(태핑음)과 수치해석으로 구한 타격음을 비교하였다. 손상이 없는 복합재료 구조물과 손상이 있는 복합재료 구조물을 제작하고 타격 실험을 통해 타격음과 타격력을 측정하였다. 타격음의 수치 모사를 위해 동적접촉 알고리듬을 이용한 유한요소법과 경계요소법을 이용하였다. Wavelet packet transform에 근거한 특성 추출법을 이용하여 타격음으로부터 손상 판단을 위한 특성을 추출하였다. 손상이 없는 구조물과 손상이 있는 구조물의 특성을 비교하기 위해, 특성 지수를 정의하였다. 실험 결과와 수치해석 결과의 비교를 통해 타격음 계산에 사용된 수치모델의 타당성을 밝혔다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.208-213
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• 2014

공동주택의 천장구조는 바닥충격음을 변화시키는 영향요소중의 하나이다. 천장구조의 진동응답 특성이 바닥충격음에 영향을 주는 요소를 확인하기 위해 천장구조의 달대를 제거하여 콘크리트 슬래브의 진동이 천장구조에 전달되지 않는 무달대 천장구조를 개발하였다. 달대가 시공된 일반 천장구조와 대비하여 무달대 천장구조의 천장판 가속도와 바닥충격음 레벨을 비교하였다. 무달대 천장구조를 사용함으로서 콘크리트 슬래브의 진동이 천장구조에 전달되는 것을 절연되어 천장구조의 진동응답 증폭을 저감시킬 수 있었으며, 저주파 대역의 바닥 충격음 증폭 또한 저감시킬 수 있었다. 일반 천장구조는 100 Hz 이하에서 천장구조의 진동응답이 증폭되어 저주파 대역 바닥충격음이 증폭되었다.