고정원을 위한 micro-implant 매식시 drilling 유무에 따른 안정성에 관한 연구

김종완,장영일 대한치과교정학회 2002 대한치과교정학회지 Vol.32 No.2

본 연구는 교정적 고정원을 얻기 위하여 micro-implant(Osas ??, 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 군과 drill-free method 군으로 나누어 매식하였다. 매식한 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 ??, Ormco)으로 200 gm-300 gm의 힘을 적용하였다. 동요도 검사는 희생 전에 Periotest ??(Siemens)로 측정하였다. 매식 12주 후에 관류고정 하였으며 시편은 레진 포매하여 Exakt system ??(Exakt)을 이용하여 비탈회 표본을 제작하였다. 표본은 H-E 염색한 뒤, 광학 현미경 상에서 점경하여 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. The aim of this study was to investigate experimentally the mechanical and histological effect of drilling process on the stability of micro-implant used for the orthodontic anchorage. For this purpose, 32 micro-implants(Osas ??, Epoch medical, Ø1.6 mm) were inserted into maxilla, mandible and palate in two beagle dogs. 16 micro-implant(8 per dog) were inserted after drilling with pilot drilling bur (drill method group). 16 micro-implants(8 per dog) were inserted without drilling (drill free method group). After 1 week, micro-implants were loaded by means of Ni-Ti coil spring(Ni-Ti springs-extension ??, Ormco) with 200-300 gm force. Following 12 weeks, the micro-implants and the surrounding bone were removed. Before sacrifice, the mobilities were tested with Periotest ??(Siemens). Undecalcified serial sections with the long axis were made and the histologic evaluations were done. The results of this study were as follow ; 1. The osseointegration was found in both of drill-free method group and drill method group 2. Two of drill method group and one of drill-free method group in 32 micro-implants were lost after loading. 3. The mobilities of drill-free method group were less than drill method group 4. The bone contact on surface of micro-implants in drill-free method group was more than drill method group but there was no significant difference between groups. 5. The bone density in threads of micro-implants in drill-free method group was more than drill method group and there was significant difference between groups. These results suggest that drill-free method in insertion of micro-implants is superior to drill method on the stabilities, bone remodeling and osseointegrations under early loading.

마이크로 드릴에 의한 구멍 가공시 드릴의 손상과 구멍의 관찰

배명일 한국기계기술학회 2016 한국기계기술학회지 Vol.18 No.4

In this study, i machined micro hole to PCB(Printed circuit board) with ultra precision spindle system for mechanical micro drilling. For this i utilized 0.4∼0.6 ㎜ micro drill and observed cutting edge and hole. Results are as follows; in case of drilling with 0.4∼0.6 ㎜ micro drill, micro hole was made specific range of diameter up to 300 times drilling and micro drilled diameter was bigger than micro drill’s diameter at 300 times over. Error ratio of drilled diameter and damaged hole diameter was within 5 % and 17 %. I observed 0.4 ㎜and 0.6 ㎜micro drill’s cutting edge after 500 times drilling and confirm cutting edge width variation and damage, same result found 1000 times drilling with 0.5 ㎜ micro drill.

극소량 절삭유 분무를 이용한 마이크로 드릴링 가공특성에 관한 실험적 연구

남택수(Taek-Soo Nam),이필호(Pil-Ho Lee),Chengjun Li,이상원(SangWon Lee) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11

This paper presents the experimental characterization of micro drilling process under conditions of dry, compressed air and minimum quantity lubrication (MQL). A series of micro drilling experiments were conducted in the miniaturized desktop machine tool system. Micro drills with the diameter of 200 um were used in the experiments, and the workpiece was aluminum 6061. The experimental results showed that MQL reduced the adhesion of chips when compared with the case of dry micro drilling. As a result, it was observed that the magnitudes of average drilling torque and thrust force were decreased and the tool life of micro drills was extended in the case of MQL micro drilling.

Chip Discharge Performance of Micro-Hole Drilling through a Glass Plate using an Electroplated Diamond Tool with Different Drill Bits

Akira Mizobuchi,Mohd Sanusi Abdul Aziz,Raja Izamshah,Tohru Ishida 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.19 No.9

This research aims to identify a high-quality, efficient, and low-cost micro-hole drilling process through glass plates that employs an electroplated diamond tool with different drill bits. Three different drill bits were tested to determine how varying the chip discharge volume influences chip discharge performance, which is an important factor that affects the effectiveness of the drilling process. The chip discharge performance of each electroplated diamond tool was experimentally investigated by observing the drilling quality and the number of the drilled holes. From the experimental results, it was found that the drilled chips could not discharge smoothly when the drill bit possesses a small chip discharge volume, leading to the drill bit breaking, which thus limits the number of drilled holes. Furthermore, the changes in thrust force and the crack size were high, and there were also cracks on the drilled glass plate. However, drilling with a drill bit that possesses a larger chip discharge volume resulted in excellent chip discharge performance and increased the number of drilled holes. This type of drill bit is effective in drilling holes through glass plates, with minimum hole defects and no issues associated with chips clogging the hole during drilling.

버어 발생을 최소화하기 위한 미세 드릴가공의 절삭 조건

이재균(Jae-Gyun Lee),왕철수(Cheol-Soo Wang) 산업기술교육훈련학회 2010 산업기술연구논문지 (JITR) Vol.15 No.1

The micro drilling process is one of the most fundamental and popularly used process in the machining and assembling process because it has high productivity and high precision. However, the problems in micro-hole machining by micro drill, it is difficult to remove chip from drilled hole and supply cutting oil. So, it is necessary to establish optimum drilling condition and develop a new drilling process. The aim of the present study was to investigate the variation of thrust which was concerned with feed rate. Also, the optimum drilling condition which could minimize burr generation was examined in step feed machining process.

Performance of a TR-iso-pulse generator in micro ED-drilling

Shin, Min-Chul,Kim, Yoo-Seok,Cheong, Hyeong-Gyun,Chu, Chong-Nam Elsevier 2019 Precision engineering Vol.56 No.-

<P><B>Abstract</B></P> <P>This study describes a TR-iso-pulse generator which has better machining performance than an RC-pulse generator in micro-electrical discharge drilling (micro ED-drilling). Although machining with a TR-pulse generator is more efficient compared to when using a RC-pulse generator in macro-scale EDM, an RC-pulse generator is often used in micro EDM because it can generate the short discharge pulse necessary to minimize the discharge energy. However, to increase the machining efficiency, it is necessary to develop a TR-iso-pulse generator capable of generating a small amount of uniform discharge energy. In this research, a TR-iso-pulse generator was constructed for micro ED-drilling. For an accurate performance comparison between an RC-pulse generator and a TR-iso-pulse generator, each pulse generator was set up to generate the same discharge energy for a single discharge. Through micro ED-drilling, material removal rate (MRR) and relative wear ratio (RWR) were measured with respect to feed rate, and then the periphery of the machined hole, longitudinal section, lateral overcut, and surface roughness were compared for machining accuracy analyses. As a result, MRR was increased by 121% and RWR was decreased by 39% in the TR-iso-pulse generator compared with the RC-pulse generator. In addition, while lateral overcut was increased by 4.63%, less amounts of re-solidified material were deposited at the periphery of the machined hole and surface roughness was also reduced by 22% in the TR-iso-pulse generator.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A TR-iso-pulse generator outperformed an RC-pulse generator in micro ED-drilling. </LI> <LI> Material removal rate increased by 121% due to the quick voltage recovery time. </LI> <LI> Relative wear ratio decreased by 39% owing to the absence of reverse current. </LI> <LI> Surface roughness decreased by 22% because of short and uniform discharges. </LI> <LI> Less amounts of re-solidified material were deposited at the periphery of holes. </LI> </UL> </P>

Machinability of Titanium Alloy (Ti-6Al-4V) in Environmentally-Friendly Micro-Drilling Process with Nanofluid Minimum Quantity Lubrication Using Nanodiamond Particles

남정수,이상원 한국정밀공학회 2018 International Journal of Precision Engineering and Vol.5 No.1

This paper discusses the experimental characterization on micro-drilling process of titanium alloy (Ti-6Al-4V), which is one of representative difficult-to-cut materials, with the nanofluid minimum quantity lubrication (nMQL). The miniaturized machine tool system is set up, and then, a series of micro-drilling experiments are performed under compressed air (CA), pure MQL and nMQL for a comparison. For the nanofluid, nanodiamond particles with the sizes of 35 nm and 80 nm are chosen, and the base fluid is vegetable oil. For the micro-drilling process, an uncoated carbide twist drill having the diameter of 300 µm is used for drilling holes in the titanium alloy workpiece. The experimental results show that the nMQL can reduce the drilling torques and thrust forces, but its effect is more obvious at a low feed rate (10 mm/min). In addition, the edge corner radii and hole circularity errors are significantly reduced in the case of small size (35 nm) and high weight concentration (0.4 wt. %) of the nanodiamond particles at the low feed rate. It is also found that the nMQL effectively mitigates chip adhesion of drill tool and burr of drilled holes.

Micro Drilling of Single Crystal SiC Using Polycrystalline Diamond Tool

이의석(Ui Seok Lee),양찬영(Chan Young Yang),이주현(Ju Hyeon Lee),김보현(Bo Hyun Kim) Korean Society for Precision Engineering 2021 한국정밀공학회지 Vol.38 No.7

Silicon carbide (SiC) has been used as a material for semi-conductor, molds, and micro-electro-mechanical systems (MEMS) because of its superior thermal, electrical, and mechanical properties. However, micro machining of SiC is very challenging due to its hardness and brittleness. This paper presents an experimental study of micro hole drilling of SiC. In this study, polycrystalline diamond (PCD) was used as a tool to overcome the hardness of SiC. The micro PCD tool with a diameter of 110 μm was fabricated by micro electrical discharge machining (EDM). Micro drilling was conducted with varying machining parameters such as tool rotational speed and feed rate. Effects of surface roughness of the tool and lubrication method were also investigated.

마이크로 드릴링을 이용한 미세압출다이 가공에 관한 연구

민승기,제태진,이응숙,이동주 한국공작기계학회 2003 한국공작기계학회 춘계학술대회논문집 Vol.2003 No.-

The micro-extruding die is a die for manufacturing of fine-wire by extruding process. The fine-wire made from the micro-extruding can be effectively applied to fields of semiconductor parts and medical parts etc. It is predicted that the demand of fine-wire in industry is more and more increasing. In this study φ50μm micro-drill which is coated with diamond is used for drilling of super micro-hole sizes. For the machining of taper parts of entrance and exit, drill having φ9mm inclination angle 20˚ and angle 30˚ is used. This is useful for anti tool-breakage and excessive too-wear in drilling process. After micro-drilling, the polishing process by diamond abrasive and polishing wood is carried out for increasing surface roughness.

Defect Detection of Laser Drilling Micro Holes Using Photodiode Sensor and Autoencoders

S. M. Lee(이수민),M. K. Jeong(정민기),D. W. Yeo(여대원),Y. K. Lee(이용관) Korean Society for Precision Engineering 2021 한국정밀공학회 학술발표대회 논문집 Vol.2021 No.11월

Laser micro drilling is a manufacturing method commonly used to drill holes of microscopic diameters into metals. The size and quantity of holes drilled pose a challenge in accurate, thorough, and time-efficient quality control. We observed an abnormal amount of visible light scattered when the laser failed to drill through the material and created a defective hole. Using this observation, we hypothesized there would be a difference in the pattern of light around the work area during successful and defective drilling. In this paper we propose the usage of a photodiode sensor and autoencoders for in-situ progress monitoring and defect detection of laser micro drilling. We generated simulation data of the expected power over time prior to the data collection and trained CNN and LSTM autoencoders as a proof of concept. The photodiode sensor was installed at an angle to the 1064 nm Nd:YAG Laser to collect scattered, reflected and emitted light. Data collected showed high similarity to the general pattern of simulated data.