• 구강회복응용과학지
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• 제28권4호
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• pp.423-439
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• 2012

NobelGuide$^{TM}$ 임플란트 시스템은 골량과 골질을 수술 전에 판단하여 점막을 젖히지 않고 미리 계획된 스텐트와 보철물을 이용하여 즉시하중을 부여하는 CAD/CAM 기반의 임플란트 보철 치료방법이다. 환자의 불편감을 최소화하여 미리 예측 가능한 위치에 임플란트를 식립함으로써 술 후 합병증 및 보철과정을 간소화 할 수 있는 장점이 있다. 본 증례의 환자는 56세 남성으로 상,하악 부분 무치악 상태였으며, 상악전치부 보철물 탈락과 하악 전치가 흔들린다는 주소로 내원하였다. 이에 상악 잔존치 모두와 하악 4전치 발거 및 치주치료를 실시한 뒤 임시 의치를 6개월간 사용하여 발치와 치유 및 의치 적응여부를 평가하였다. 골량은 충분하다고 판단되었고 환자의 협조도와 경제적인 여건, 전신건강 등 여러 사항이 양호하여 CAD/CAM 기반의 수술템플렛을 이용한 무판막 수술을 통해, 미리 제작된 임시 고정성 보철물로 즉시하중을 부여하는 상악 NobelGuide$^{TM}$ 임플란트 시스템을 계획하였다. 사용중인 임시의치를 이용하여 제작한 방사선 스텐트로 CT를 촬영하고, computer based planning (Procera$^{(R)}$ software)을 통해 3차원적인 골형상과 각 부위별 단면상을 참고하여 상악에 8개의 임플란트 식립체를 생역학적 관점 및 골조건을 고려하여 분산 배치하였다. 미리 제작된 임시 고정성 보철물을 임플란트 수술 후 즉시 장착 및 하중을 부여하여 기능하도록 하였으며 6개월 후 골유착 정도를 평가한 뒤 금속구조물을 이용한 최종 보철물을 제작하였다. 하악의 경우 전치부 도재전장주조금속관과 우측 구치부 임플란트 보철물 제작을 통해 상, 하악 치료를 마무리하였다.

• 구강회복응용과학지
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• 제27권2호
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• pp.233-245
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• 2011

임플란트 시술에서 CAD/CAM을 포함한 컴퓨터 기술의 발달은 단순히 임플란트를 보다 정확하고, 예측 가능하게 식립하는 것뿐 아니라, 무피판(flapless) 수술과 즉시하중을 가능하게 하였다. 그러므로 술후 출혈과 불편감의 감소 및 시술시간과 치유기간을 단축시키는 장점이 있으며, 시술 후 즉시 보철물을 장착해 줌으로써 환자의 구강기능을 단기간에 회복시키고 경조직과 연조직의 형태를 보존하여 최종보철 시 유리한 환경을 만들어 줄 수 있게 되었다. 본 증례는 상 하악 무치악 상태로 내원한 40세 남성 환자로 하악 총의치의 불안정성 및 불편감 등을 호소하였으며, 하악에 임플란트 지지 고정성 보철물을 통한 수복을 원하였다. 충분한 골량, 환자의 참여도, 경제적인 여건, 전신적인 건강 등을 고려하여 하악에는 CAD/CAM 기반의 수술용 스텐트를 이용한 수술 및 미리 제작된 고정성 임시보철물을 이용하여 즉시하중을 부여하는NobelGuide 보철을 계획하였으며, 상악에는 총의치를 계획하였다. 환자의 안모를 평가하여 임시의치를 제작하였으며, 복제한 임시의치를 바탕으로 스텐트를 제작하고, 컴퓨터단층촬영을 시행하였다. 3차원으로 변환된 영상을 기반으로 하악에 7개의 고정체를 생역학적 조건과 치조골의 상태에 맞게 분산 배치하였다. 제작된 수술용 스텐트에 맞게 주모형을 제작하고, 임시고정성 보철물을 제작하여 장착함으로써 즉시하중을 부여하였다. 식립 3개월 후 골유착 정도를 평가하고 최종보철물을 제작하였다. 추후 발생할 수 있는 상악 골흡수를 방지하기 위해 주기적인 내원 및 검사를 통해 성공적인 치료가 될 수 있도록 노력하였다.

• 한국산학기술학회논문지
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• 제19권6호
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• pp.160-166
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• 2018

세계적으로 반도체장비 시장은 오래전부터 성장하고 있다. 유체제어시스템은 반도체 제조 장비에 사용되어지는 배관을 집적화시켜 유체의 공급을 제어할 수 있도록 모듈화, 소형화한 시스템이다. 반도체의 제조공정은 여러 종류의 맹독성 가스를 필수적으로 다루어야 한다. 특히 실제 작업 공정에서는 이러한 맹독성 가스의 정밀한 제어가 필요하다. 이러한 맹독성가스를 제어하는 시스템은 피팅, 밸트, 튜브, 필터, 레귤레이터 등 다양한 부품들로 구성되어 있다. 이 부품들은 누출 없이 고압 가스를 계속 제어해야 하기 때문에 정밀하게 제조되어야 하고 내부식성이 있어야 한다. 이를 위해 금속 블록 및 금속 가스킷의 표면 가공 및 경화 기술을 연구해야 한다. 본 논문에서는 이러한 유체제어시스템에서 가장 기본이 되는 V-Block의 직경, 유량, 각도를 다르게 설계하여 내부에서 어떠한 유동흐름을 보이는지 파악하고자 하며, 유체제어시스템에서 가장 기본이 되는 유체제어벨브 시스템의 내부 유동해석을 통하여 안정적인 유량을 공급할 수 있는 설계의 최적화에 대해 연구하고 분석하였다.

• 한국정밀공학회지
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• 제30권1호
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• pp.11-17
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• 2013

'Multi-scale mass-deployable cooperative robots' is a next generation robotics paradigm where a large number of robots that vary in size cooperate in a hierarchical fashion to collect information in various environments. While this paradigm can exhibit the effective solution for exploration of the wide area consisting of various types of terrain, its technical maturity is still in its infant state and many technical hurdles should be resolved to realize this paradigm. In this paper, we propose to develop new design and manufacturing methodologies for the multi-scale mass-deployable cooperative robots. In doing so, we present various fundamental technologies in four different research fields. (1) Adaptable design methods consist of compliant mechanisms and hierarchical structures which provide robots with a unified way to overcome various and irregular terrains. (2) Soft composite materials realize the compliancy in these structures. (3) Multi-scale integrative manufacturing techniques are convergence of traditional methods for producing various sized robots assembled by such materials. Finally, (4) the control and communication techniques for the massive swarm robot systems enable multiple functionally simple robots to accomplish the complex job by effective job distribution.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2000년도 제18회 학술발표회 논문개요집
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• pp.77-77
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• 2000

Titanium oxide (TiO2) thin films have valuable properties such as a high refractive index, excellent transmittance in the visible and near-IR frequency, and high chemical stability. Therefore it is extensively used in anti-reflection coating, sensor, and photocatalysis as electrical and optical applications. Specially, TiO2 have a high dielectric constant of 180 along the c axis and 90 along the a axis, so it is highlighted in fabricating dielectric capacitors in micro electronic devices. A variety of methods have been used to produce patterned self-assembled monolayers (SAMs), including microcontact printing ($\mu$CP), UV-photolithotgraphy, e-beam lithography, scanned-probe based micro-machining, and atom-lithography. Above all, thin film fabrication on $\mu$CP modified surface is a potentially low-cost, high-throughput method, because it does not require expensive photolithographic equipment, and it produce micrometer scale patterns in thin film materials. The patterned SAMs were used as thin resists, to transfer patterns onto thin films either by chemical etching or by selective deposition. In this study, we deposited TiO2 thin films on Si (1000 substrateds using titanium (IV) isopropoxide ([Ti(O(C3H7)4)] ; TIP as a single molecular precursor at deposition temperature in the range of 300-$700^{\circ}C$ without any carrier and bubbler gas. Crack-free, highly oriented TiO2 polycrystalline thin films with anatase phase and stoichimetric ratio of Ti and O were successfully deposited on Si(100) at temperature as low as 50$0^{\circ}C$. XRD and TED data showed that below 50$0^{\circ}C$, the TiO2 thin films were dominantly grown on Si(100) surfaces in the [211] direction, whereas with increasing the deposition temperature to $700^{\circ}C$, the main films growth direction was changed to be [200]. Two distinct growth behaviors were observed from the Arhenius plots. In addition to deposition of THe TiO2 thin films on Si(100) substrates, patterning of TiO2 thin films was also performed at grown temperature in the range of 300-50$0^{\circ}C$ by MOCVD onto the Si(100) substrates of which surface was modified by organic thin film template. The organic thin film of SAm is obtained by the $\mu$CP method. Alpha-step profile and optical microscope images showed that the boundaries between SAMs areas and selectively deposited TiO2 thin film areas are very definite and sharp. Capacitance - Voltage measurements made on TiO2 films gave a dielectric constant of 29, suggesting a possibility of electronic material applications.

• 한국정밀공학회지
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• 제3권2호
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• pp.62-75
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• 1986

An experimental investigation of the machining characteristics such as cutt- ing resistance, surface roughness and tool wear in turning the test pieces of SM45C steel with both coated and uncoated carbide tool tips under various cutting conditions was conducted. Also a specially designed simple vibration damping device was experimentally evaluated for its effectiveness on machined surface roughness and a vibration test was conducted to confirm its ability to reduce the amplitude. Based on these tests finding, the following conclusions are made; 1. The cutting resistance($\textrm{p}_{1}$) increases as the depth of cut(d) increases at fixed feed rate(f) over the cutting speed(v) range of 43-226 m/min and p decreses about 18% average when V is increased for fixed d and f. At V= 226m/min, $\textrm{p}_{1}$/for A, C tips are about the same level but $\textrm{p}_{1}$ for B tip is 15% less than A, C tips. 2. The specific cutting resistance(Ks) at V=226 m/min was derived for A, B, C tips respectively and the value of Ks for B rip is about 20% less than A, C tips. 3. The surface roughness(Ra) improves significantly as the cutting speed(V) is increased and this effect was greater when V>100 m/min. On the other hand, Ra deteriorates as the feed rate(f) is increased and this trend was accelerated when f>0.3 mm/rev. With regard to the difference of Ra values among A, B, C tips, at V=226m/min, d=0.4mm, and f=0.31-0.61mm/rev, Ra values for B.C tips are about 17% less than tip A. 4. The experimental tool wear equations were derived for A, B, C tips and from these equations, the tool life($\textrm{T}_{\textrm{L}}$) baced on the I.S.O. criteria was calculated to be $\textrm{T}_{\textrm{L}}$<$\textrm{T}_{\textrm{LB}}$<$\textrm{T}_{\textrm{LC}}$ for both flank wear($\textrm{V}_{\textrm{B}}$) and boundary wear($\textrm{V}_{\textrm{N}}$). Hence, the coated tips are superior to the uncoated tip and tip C is considered to be the best. 5. The cutting resistance may be slightly reduced and the surface rounghness improved when the damper is used especially when V>100 m/min. Therefore this damping device is considered to be effective and practical. The experimental surface roughness equations were also derived. Based on the vibration test, it is established that the surface roughness improvement was the result of amplitude reduction made possible by the damper.

• 한국레이저가공학회:학술대회논문집
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• 한국레이저가공학회 1998년도 추계학술발표대회 초록개요집
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• pp.0-0
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• 1998

-Part I- As market needs become more various, the production of smaller quantities of a wider variety of products becomes increasingly important. In addition, in order to meet demands for more efficient production, long-term unmanned factory operation is prevailing at a remarkable pace. Within this context, laser machines are gaining increasing popularity for use in applications such as cutting and welding metallic and ceramic materials. FANUC supplies four models of $CO_2$ laser oscillators with laser power ranging from 1.5㎾ to 6㎾ on an OEM basis to machine tool builders. However, FANUC has been requested to produce laser oscillators that allow more compact and lower-cost laser machines to be built. To meet such demands, FANUC has developed six models of Slab type YAG laser oscillators with output power ranging from 150W to 2㎾. These oscillators are designed mainly fur cutting and welding sheet metals. The oscillator has an exceptionally superior laser beam quality compared to conventional YAG laser oscillators, thus providing significantly improved machining capability. In addition, the laser beam of the oscillator can be efficiently transmitted through quartz optical fibers, enabling laser machines to be simplified and made more compact. This paper introduces the features of FANUC’s developed Slab type YAG laser oscillators and their applications. - Part II - All-solid-state lasers employing laser diodes (LD) as a source of pumping solid-state laser feature high efficiency, compactness, and high reliability. Thus, they are expected to provide a new generation of processing tools in various fields, especially in automobile and aircraft industries where great hopes are being placed on laser welding technology for steel plates and aluminum materials for which a significant growth in demand is expected. Also, in power plants, it is hoped that reliability and safety will be improved by using the laser welding technology. As in the above, the advent of high-power all-solid-state lasers may not only bring a great technological innovation to existing industry, but also create new industry. This is the background for this project, which has set its sights on the development of high-power, all-solid-state lasers with an average output of over 10㎾, an oscillation efficiency of over 20%, and a laser head volume of below 0.05㎥. FANUC Ltd. is responsible for the research and development of slab type lasers, and TOSHIBA Corp. far rod type lasers. By pumping slab type Nd: YAG crystal and by using quasi-continuous wave (QCW) type LD stacks, FANUC has already obtained an average output power of 1.7㎾, an optical conversion efficiency of 42%, and an electro-optical conversion efficiency of 16%. These conversion efficiencies are the best results the world has ever seen in the field of high-power all-solid-state lasers. TOSHIBA Corp. has also obtained an output power of 1.2㎾, an optical conversion efficiency of 30％, and an electro-optical conversion efficiency of 12%, by pumping the rod type Nd: YAG crystal by continuous wave (CW) type LD stacks. The laser power achieved by TOSHIBA Corp. is also a new world record in the field of rod type all-solid-state lasers. This report provides details of the above results and some information on future development plans.

• 실천공학교육논문지
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• 제13권2호
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• pp.327-332
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• 2021

교육용으로 사용되는 피삭재(소재)는 SM20C, Al6061, 아크릴 등의 소재를 사용한다. SM20C 소재는 탄소강으로서 자격증 시험 및 기능경기대회에서 많이 사용되지만 산업현장에서도 많이 사용된다. Al6061 소재는 탄소강에 비하여 경도가 낮아지고 전성(연성)이 강한 소재이기에 공구의 구성인선이 많이 발생하는 소재 라고 한다. 아크릴 소재를 이용하여 학생들에게 실습지도 하면 어느 부분에서 과다 절삭으로 인하여 진동이 발생하고 공구의 파손이 발생하는 소재이다. 이러한 과정에서 5축장비인 2NC헤드에게 가해지는 충격이 정밀도 제어에는 어느정도 영향을 줄 수 있는지 알아본다. 5축장비의 가장 취약한 부분은 AC축을 제어하는 헤드가 가장 약한 부분이라 할 수 있다. 이 부분의 정밀도 및 누적 공차가 발생할 경우 모든 제품의 정밀도가 떨어지는 현상이 발생한다. 따라서 2NC헤드의 핵심적인 부분, 스핀들 하우징은 Al7075 T6(미국 알코아사) 소재를 사용하고 전체 바디는 FCD450 (구상흑연주철) 사용하여 진행하였다. 이 두가지 소재에서 작용되는 진동 및 절삭 과정에서 힘을 극한조건에서 유한요소 해석으로 적용되는 값을 밝혀 내고자 해석을 진행하였다. 이러한 해석 데이터를 활용하여 학생들이 5축절삭 보다 5축 가공기의 구조를 보고 이해하는데 도움이 되기를 기대한다.

• Design & Manufacturing
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• 제13권2호
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• pp.17-21
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• 2019

In this study, selective laser sintered 3D printing mold core and metal core were used to investigate the difference of the thickness shrinkage from the gate of the injection molded part at a constant interval. SLS 3D printing mold core was made of nylon-based PA2200 powder and the metal core was manufactured by conventional machining method. As the PA2200 powder material has low strength, thermal conductivity and high specific heat characteristics compared with metal, molding conditions were set with the consideration of molten temperature and injection pressure. Crystalline resin(PP) and amorphous resin(PS) with low melting temperature and viscosity were selected for the injection molding experiment. Cooling time for processing condition was selected by checking the temperature change of the cores with a cavity temperature sensor. The cooling time of the 3D printing core was required a longer time than that of the metal core. The thickness shrinkage of the molded part compared to the core depth was measured from the gate by a constant interval. It was shown that the thickness shrinkage of the 3D printing core was 2.02 ~ 4.34% larger than that of metal core. In additions, in the case of metal core, thickness shrinkage was increased with distance from the gate, on the contrary, in the case of polymer core showed reversed aspect.

• 대한치과기공학회지
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• 제41권2호
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• pp.63-69
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• 2019

Purpose: The purpose of this study is to evaluate the effect of CAD/CAM system milling tool wear on the marginal and internal fit of PMMA implant interim prosthesis three-dimensional manner. Methods: A total of 20 crowns were fabricated with CAD/CAM method. Their designs were unified to first molar of the left maxilla. The Customized abutments were prepared and scanned with on optical model scanner. Five crowns were milled by the newly replaced tool (1st milling), and 15 crowns were milled by 2nd, 3rd, 4th milling tool. The marginal and internal fit of 20 interim crowns were measured using the triple-scan protocol. Results: Statistically significant difference was found between the $1^{st}$ milling group ($51.8{\pm}14.6{\mu}m$) and the $3^{rd}$, $4^{th}$ milling group ($128.6{\pm}43.8{\mu}m$, $146.2{\pm}38.1{\mu}m$, respectively) at the distal margins. In the mesial margins, There was a statistically significant difference between the $1^{st}$ milling group ($63.6{\pm}25.9{\mu}m$) and the $3^{rd}$, $4^{th}$ milling group ($137.2{\pm}25.9{\mu}m$, $186.8{\pm}70.6{\mu}m$, respectively). In the distal line angle, significant difference was found between the $1^{st}$, $2^{nd}$, $3^{rd}$ milling groups and the $4^{th}$ milling group. In the mesial axial wall, significant difference was found between the $1^{st}$ milling group ($52.2{\pm}20.3{\mu}m$) and the $3^{rd}$, $4^{th}$ milling groups ($22.8{\pm}8.8{\mu}m$, $7.8{\pm}5.7{\mu}m$). Conclusion: As a result of the experiment, decrease of the marginal and internal fit was statistically significant as the number of machining cycles increased. In order to produce clinically excellent restorations, it is recommandable to consider the condition of the milling tool wear, when designing the restoration with CAD program.