• 한국기계가공학회지
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• 제11권3호
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• pp.29-34
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• 2012

This paper reports some experimental results in high speed rigid tapping of magnesium alloy(AZ91D). M3 spiral tap and high speed spindle tapping center of gantry type were used in experiments and thrust forces were measured. The experimental results indicate that the thrust forces are proportional to the spindle speed and depth of cut. The thrust forces increase as the depth of cut increases. M3 Tapping was achieved at the spindle speed of 10,000rpm, depth of cut of 1.5D and total stroke of 32mm.

• 대한기계학회논문집
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• 제18권12호
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• pp.3195-3201
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• 1994

In order to analytically predict tapping torque and thrust force in high speed tapping, a cutting model for main cutting edge with a uniformly restricted tool-chip contact area were developed. From this model equations are derived for the prediction of tapping torque given the cutting conditions, tap geometry, and an empirical factor which is related to the workmaterial. Computed values of torque is shown to compare favorably with those obtained from tapping tests on 16MnCr5. The applied torque about the cutting edge of teeth at lead chamfer is estimated respectively and it is shown that observed value is gradually decreased with following teeth.

• 한국정밀공학회지
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• 제18권11호
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• pp.67-73
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• 2001

This paper aims at developing a torque model for the high-speed tapping with small-diameter taps. As recent industries such as automobile and information technology grows, taps smaller than 5mm in diameter are needed much more. In that occasion, the friction force between a tap surface and a workpiece plays much more important role in the tapping torque than in he larger tapping. Tapping mechanism was analysed based on the tap geometry. It has two steps : one is a forward cutting composed of the chamfered threading and full threading and the other is the backward cutting. The torque by the cutting force in the chamfered threading is calculated using the cutting area and the specific cutting force while the torque by the friction force, which is rather dominant than the cutting force both in the full threading and in the backward cutting, is calculated using the normal force on the threads and the friction coefficient. The experiment has shown that the results by the proposed torque model fit quite well with the acutal measurements within the error of 10%.

• 인간행동과 음악연구
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• 제13권1호
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• pp.1-18
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• 2016

본 연구는 아동의 리듬 수행 능력과 인지 능력 간 상관관계를 알아보고자 하였다. 이를 위해 평균 연령 9세의 초등학생 59명을 대상으로 iPad 기반 리듬 수행 검사, 숫자 외우기 검사(DST), 아동 색선로 검사(CCTT), 키보드를 활용한 자가탭핑 검사를 진행하였다. 검사 결과, 리듬 재산출의 정확도(accuracy)를 측정하는 리듬 수행 검사 1단계 10개 문항은 자가탭핑 평균속도(s)와 유의한 상관관계가 나타났으며, 리듬 수행 검사 2단계에서 측정하는 그룹핑(grouping) 능력은 CCTT 검사 결과와 유의한 상관관계가 있었다. 특히 문항 특성에 따른 결과를 분석한 결과 일정한 리듬이 두 번 이상 연속으로 반복되어 제공되는 리듬꼴의 정확한 수행은 자가탭핑 속도와 부적 상관관계가 있었으며, 분할박이 많은 리듬꼴의 리듬 수행력은 CCTT, 즉 집행기능과 유의한 상관관계가 있는 것으로 나타났다. 본 연구 결과 리듬 재산출 과제가 초등학교 학령기 아동의 인지 기능 검사 결과와 유의한 상관관계에 있다는 것을 확인하였다. 또한 아동이 산출하는 자가탭핑 속도, 즉 내적 리듬 특성이 인지 기능과 상관관계에 있음을 알 수 있었다. 본 연구는 학령기 아동의 리듬 수행력과 관련된 기초 자료를 제시하고, 이러한 리듬수행력이 인지 기능의 측정 지표가 될 수 있는 가능성이 있음을 시사한다. 본 연구에서 도출된 결과를 통해 추후 리듬꼴의 특징 및 리듬 과제의 난이도에 따른 리듬 수행력이 학령기 아동의 인지적, 정서행동적, 음악적 특성을 다각적으로 평가할 수 있는 가능성 또한 제언되었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.243-246
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• 2000

Productivty of tapping has been increasing through the tcchnological advances in synchronization between spindle rotation and feed motion even in the high spindle speed. However, not much researches have been conducted about tapping process because its complicate cutting mechanism. In order ta investigate the characteristics of the tapping process, this paper concentrates on the analysis of curting torque behavior during one cycle of lapping. As one completc thread is performed through the whole chamfer ercuttlng, cutting torque increases highly in chamfer cutting, but smaothly in full thread cutting Functioning of the threads guide. Cutting torque in backward cutting is smaller than in Sorwerd cutting due to only friction farce in against between the tool and workpiece. And torque behavior of a periodic Sine ripple-mark was identified during one revolution of a tap.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.315-318
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• 1997

In terms of productivity, the speed of machining process has been increasing in most of engineering part. But the tapping process does not reach at enough level compared with other machining processes because of its complicate cutting mechanism. In the high speed tapping process, the one of important elements is tool monitoring system to prevent tool breakage. This paper describes tool monitoring system by acoustic emission(AE) in the tapping process. We used 2 types of AE sensors in this test. The one is commercial sensor which is used in other machining monitoring system like polishing and the other is a self-fabricated sensor for this test. In this test we purpose to find out the frequency of AE signal in tapping process and verify the possibility of applying AE sensor in in-process tapping monitoring system. Also grasp of characteristic of tapping process by AE signal is handled.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 춘계학술대회 논문집
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• pp.244-245
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• 2012

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2011년도 춘계학술대회 논문집
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• pp.1335-1336
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• 2011

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.184-187
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• 2000

This paper describes action of synchronous error between z axis and spindle axis on rigid tapping. Because rigid tapping cuts the threads synchronizing the movement of z axis to spindle rotation, synchronous error between z axis and spindle is very important. Increase of synchronous error degrades the accuracy of thread and crushes the tap in worst case. So we developed the realtime measurement system of synchronous error in order to know the action of synchronous error on rigid tapping. In result, we have known that synchronous error was increased according to rise of spindle speed and z axis speed. And because the cutting torque(M3-30Ncm∼M10-300Ncm) on rigid tapping are less than maximum motor torque(3500Ncm), it specially doesn't affect the synchronous error. The most important parameter which has affected the increase of synchronous error was acceleration/deceleration time. On worst case, spindle motor was tripped because of the excess of synchronous error. Because the acceleration/deceleration time ocuupies the most of the total cutting time, in order to move on the high speed rigid tapping, the acceleration/deceleration time of spindle must be remarkably reduced.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.304-307
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• 2002

High speed machining was accomplished. through the technological advances which covers the whole field of mechanical industry. But tapping have many troubles because of its complicate cutting mechanism, for example. tool damage, chip elimination and synchronization between spindle rotation and feed motion. But High speed tapping is so important that it marches in step with the flow of the times and make improvement in the productivity. In this paper we analyze mechanism of high speed synchronized tapping with the signal of tapping torque and spindle speed obtained through the newly developed high speed tapping machine(NTT-30B). We made an experiment with this machine on condition of various speed from 1000rpm to 10000rpm. As one complete thread is performed through the whole chamfer cutting, cutting torque increases highly in chamfer cutting, but smoothly in full thread cutting functioning of the threads guide. And the size of cutting torque according to spindle speed(rpm) was not enough of a difference to be conspicuous.