• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.1043-1046
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• 2002

In this paper, drill tests were carried out by modifying drill geometry for burr minimization. Final objective of this study is to develop compatible drill shape for minimization of burr formation. These experimented results with modified drill are measured with laser sensor after performing drilling with variable material. Simultaneously, the cutting force and the torque of various drill geometry have been observed with same cutting condition to judge drill stability. As a result, burr was minimized in step drill with 75$^{\circ}$ step angle at every material.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.911-914
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• 1997

This Experiment was carried out for bur minimization in drilling. New drill geometries are proposed to minimize the burr formation in drilling operation. Three types of drills are made, champer, round and step drill. The burr formed in first cutting by front cutting edge ca be removed in second cutting by the cutting edges in chamfer, round edge and step. New burrs are formed by second cutting and can be minimized according to the change of drill geometry like, chamfer size and angle, corner radius in round drill and step size and angle in step drill. To measure the burr formed in drilling, laser sensor is used.

• 대한치과교정학회지
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• 제32권2호통권91호
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• pp.107-115
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• 2002

본 연구는 교정적 고정원을 얻기 위하여 micro-implant(Osas$^{(R)}$, Epoch medical)를 drill method와 drill-free method로 매식시, 조기 교정력에 대한 각각의 경우 micro-implant의 역학적 안정성 및 조직학적 생체 적합도의 차이를 알아보고자 시행하였다. 두 마리의 실험견(beagle dog)을 대상으로 상, 하악 협측과 구개부위에 좌우측을 구분하여 drill method 군과drill-free method 군으로 나누어 매식하였다. 매식 한 재료는 직경 1.6 mm의 micro-implant를 사용하였으며, drill method 군 16개, drill-free method 군 16개, 총32개의 micro-implant를 식립하였다. 교정력은 매식 후 1주 뒤에 Ni-Ti coil spring(Ni-Ti springs-extension$^{(R)}$, Ormco)으로 200 gm - 300 gm의 힘을 적용하였다. 동요도 검사는 희생 전에 Periotest$^{(R)}$(Siemens)로 측정하였다. 매식 12주 후에 관류고정 하였으며 시편은 레진 포매하여 Exakt system$^{(R)}$(Exakt)을 이용하여 비탈회 표본을 제작하였다. 표본은 H-E 염색한 뒤, 광학 현미경 상에서 검경하여 조직학적 소견을 분석하였고 조직계측학적 측정은 골접촉률과 골밀도로 분석하였다. 위와 같은 실험을 통하여 매식한 micro-implant의 탈락률과 동요도, 골접촉률 및 골밀도로 drill method 군과 drill-free method 군의 역학적 안정성 및 조직학적 생체 적합도를 비교, 분석한 결과 다음과 같은 결론을 얻었다. 1. micro-implant와 골의 계면은 기계적 접촉 뿐만 아니라 골유착도 있었다. 2. micro-implant의 탈락은 drill method 군이 더 높았다. 3. 동요도는 drill method 군이 전반적으로 더 컸다. 4. micro-implant와 골접촉 정도는 전반적으로 drill-free method 군에서 양호했다. 5. micro-implant 나사산 사이 내에 존재하는 골밀도는 전반적으로 drill-free method 군에서 더 높았다. 결론적으로, micro-implant는 매식시 drill-free method가 drill method보다 탈락률과 동요도 및 골접촉률과, 골밀도에서 더 우수한 결과를 보여 drilling 과정이 안정성과 골조직 치유 및 골유착에 영향을 미친다고 판단된다.

• 한국정밀공학회지
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• 제19권11호
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• pp.183-191
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• 2002

Drilling tests were carried out using drills with various drill shapes for burr minimization. Final objective of this study is to develop compatible drill shape for minimization of burr formation. For experiments, general carbide drills, round drills, chamfered drills and step drills are designed and manufactured. Burrs are formed by various cutting conditions and in 4 different work materials. Laser sensor is used to measure burr geometries. Cutting forces in drilling are also measured and compared in every drill. As a result of the experiments, step drills with specific step angle and step diameter are suggested for burr minimization.

• 한국공작기계학회논문집
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• 제11권2호
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• pp.103-111
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• 2002

Out of all metal-cutting process, the hole-making process is the most widely used. It is estimated to be more than 30% of the total metal-cutting process. It is therefore desirable to monitor and detect drill wear during the hole-drilling process. One important aspect in controlling the drilling process is monitoring drill wear status. There are two systems, Basic system and Online system, to detect the drill wear. Basic system comprised of spindle rotational speed, feed rates, thrust torque and flank wear measured by tool microscope. Outline system comprised of spindle rotational speed feed rates, AE signal, flank wear area measured by computer vision, On-line monitoring system does not need to stop the process to inspect drill wear. Backpropagation neural networks (BPNs) were used for on-line detection of drill wear. The output was the drill wear state which was either usable or failure. This paper deals with an on-line drill wear monitoring system to fit the detection of the abnormal tool state.

• 한국정밀공학회지
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• 제16권7호
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• pp.101-108
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• 1999

A reliable and practical monitoring of drill breakage is a crucial technique in automatic machining system. In this study, a real-time monitoring system was developed to predict drill breakage using both spindle and z-axis motor current. Drill breakage is monitored by detecting the level of residual motor current which is obtained through the moving average filter algorithm. The residual exhibits a feature of sharp decrease just before drill breakage. Therefore, drill breakage can be predicted by detecting this characteristic of residual component. Z-axis motor current is better to predict the drill breakage than spindle motor current, because the former is faster in response than the latter when drill breakage is occurred. The evaluation experiments have shown that the developed monitoring system works very well.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.1063-1067
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• 1997

A study of carbide step drill cutting ability is highly progessing the step drill with more then twice diameter rate is so difficult in regrinding and very easy to damage during machining. As the machining of step drill for closed hole is occur to breakage at small diamter poistion, so it is very difficult to machinine. Thue, in this experiment, We investance roundness and surface roghness by machining distance and were identifid that the first distance, 5~10m, was fine with 7 .mu.m but the arround of 15m was happened so much alternation. And we were indentified that after 20m was happend statable machining. The surface roughness was happened the same conditions. So application of stwp drill we think that the selection of cutting conditions need lots consideration and the study of step drill's diameter ratio ratio is carred out.

• 대한치과보철학회지
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• 제60권2호
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• pp.143-151
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• 2022

목적: 본 연구의 목적은 두 가지 다른 임플란트 드릴 조합을 사용하여 열 발생과 드릴링 시간에 따른 성능 효율성을 평가하는 것이다. 재료 및 방법: 본 연구에서는 소갈비뼈를 연구재료로 사용하였다. 표본을 시험하기 위해 소의 뼈에서 근막 및 근육을 제거하고 드릴링 영역 주위에 온도 센서를 장착했고, 드릴링 후 온도 및 시간을 측정하였다. 실험군은 이니셜 드릴 전에 사용하는 드릴에 따라 가이드 드릴 사용 그룹과 린드만 드릴 사용 그룹으로 나누었다. 가이드 드릴 사용 그룹의 드릴 사용 순서는 다음과 같다; guide drill (ø 2.25), initial drill (ø 2.25), twist drill (ø 2.80), 그리고 twist drill (ø 3.20). 린드만 드릴 사용 그룹의 드릴 사용 순서는 다음과 같다; Lindmann drill (ø 2.10), initial drill (ø 2.25), twist drill (ø 2.80), 그리고 twist drill (ø 3.20). 통계적 분석은 Mann-Whitney U test 및 Friedman test를 이용하여 집단간 차이를 분석하였다 (α = .05). 결과: 가이드 드릴 사용 그룹의 각 시편에 대한 평균 성능 효율은 0.3861 - 1.1385 mm³/s 범위를 보였고, 린드만 드릴 사용 그룹의 평균 성능 효율은 0.1700 - 0.4199 mm³/s를 보였다. 가이드 드릴을 사용한 드릴 조합은 드릴링 시간으로 계산했을 때 우수한 성능 효율을 보였다 (P < .001). 결론: 가이드 드릴 사용 그룹이 린드만 드릴 사용 그룹보다 우수한 성능 효율을 보였기 때문에, 1차 드릴링을 수행하는 과정에서 가이드 드릴의 사용이 더욱 적합하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 A
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• pp.168-170
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• 1994

Carbide-tipped twist drill of new type which is better than traditional H.S.S twist drill has been developed successfully to drill steel work-pieces with high speed. This new carbide drill consists of a characteristic flature of special shape of cutting edge, chip pocket, and flute. The special design of the chip pocket and the flute guarantees both periodic fracture and smooth transport of chips along the flute. The carbide-tipped twist drill also allows one to apply more drilling force than conventional one and produce holes with high accuracy.

• 한국정밀공학회지
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• 제17권3호
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• pp.114-121
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• 2000

A new concept drill was developed recently (or increasing accuracy and productivity in drilling operation. The burr formation in drilling causes many problems in deburring operation because burrs are formed inside holes and it is difficult to remove them. Burr formations are observed in drilling operation with a new concept drill and are compared with conventional HSS drill. Several workpieces with different materials are drilled with several cutting conditions, velocity and feed rate. The burr in drilling can be classified into three types according to the location of crack. To observe the burr formation mechanism, the cap which is formed with the new concept drill is observed and measured.