• 한국생산제조학회지
• /
• 제19권1호
• /
• pp.50-56
• /
• 2010

This paper presents a new design algorithm for piece-removing dynamical system, based on 6-Sigma DMADOV technique using ARIZ and Brainstorming. Our design target is the piece-removing system installed on a mobile platform of bead-grinding equipment. The 6-Sigma DMADOV technique guides us design process according to 6 steps, i.e., Define - Measure - Analyze - Design - Optimize - Verify. A Design strategy to reduce the weight of piece-removing dynamical system will be explored by using ARIZ, i.e.,(the abbreviation of Algorithm for Inventive Problem Solving in Russian). The ARIZ will result in a final solution that the height and angle control parts for a cutting tool should be replaced by a kinematical approach, rather than complicated mechatronic approach(using motors). The Optimize step is composed of two sub-steps: (i) Generating process for obtaining several ideas of piece-removing system by using Brainstorming technique, satisfying the final solution derived from the Design step using ARIZ, and (ii) Optimizing process for selecting the most optimal idea of piece-removing system by using Pugh's matrix from the viewpoints of weight, cost and accuracy. The laststep of Verify has shown that the final design obtained by the 6-Sigma DMADOV technique with ARIZ & Brainstormingcan improve an initial design with design requirements satisfied. In this paper, we have shown that ARIZ and Brainstorming can be cooperatively merged into 6-Sigma DMADOV to give us both a formulatedproblem-solving approach and diverse candidate solutions(or ideas) without trial-and-error efforts.

• 한국결정성장학회지
• /
• 제26권6호
• /
• pp.232-237
• /
• 2016

약물의 공결정 형성은 결정구조를 디자인하여 물리적인 성질을 제어하는 방법으로 각광받고 있다. 특히, 밀링 결정화법은 약물 공결정의 형성 여부를 판단하기 위한 스크리닝 기법으로 널리 사용되고 있는데, 대부분의 경우에 소량의 액체를 첨가하는 것이 필요하다. 본 연구에서는 액체의 첨가가 없는 밀링법을 가능하게 하기 위해서, ibuprofen/nicotinamide의 공결정화에 온도가 미치는 영향을 살폈다. 액체질소 냉각 온도와 상온에서의 밀링을 비교하였을 때, 액체질소 냉각 상태에서 공결정화가 상대적으로 효과적으로 진행된 것을 XRD, DSC 등의 분석법을 이용하여 확인하였다. 이러한 결과는 원료 물질의 유리전이 온도 이하에서 밀링하였을 때 분자의 운동성이 제한되어, 원료 결정구조의 파쇄와 공결정 유도가 효과적으로 일어나는 것으로 해석할 수 있다. 본 결과가 약물 밀링 공결정화에 응용되기 위해서는 여러 약물 공결정에 대한 추가 연구가 필요하다.

• Design & Manufacturing
• /
• 제12권1호
• /
• pp.41-46
• /
• 2018

This study proves the causes of cylinder and piston jam by scratches which is the fatal problem of hydraulic breaker through the thermal analysis and thermal-structural coupled field analysis. The trouble from the scratch is a complex problem which can be caused by manufacturing process (this is an internal factor) and the users mistake or contamination in the hydraulic circuit (these are an external factor). Hence, it's not easy to investigate the causes, also hard to prevent the recurrence. In this reason, hydraulic breaker manufacturers are trying to improve the manufacturing process such as machining, heat treatment, grinding, cleaning, also to prevent the contamination in hydraulic circuit and to remove the remains. It's being managed thoroughly by manufacturers. This study shows the effect of the temperature rise by the frictional heat generated when the piston hits the tool on the hydraulic oil while the hydraulic breaker is operating, also the temperature distribution when it starts to affect main components of hydraulic breaker. The stress and the amount of deformation also could be found through thermal-structural coupled field analysis. It proved that the stress and deformation are proportionally increased according to the temperature rise in hit area, and it affects the cylinder and the viscosity of hydraulic oil inside the cylinder when it heats up beyond the certain temperature.

• 한국정밀공학회지
• /
• 제10권2호
• /
• pp.114-125
• /
• 1993

In the present study the newly developed CAD/CAM system is applied to the process of the molding design, machining for mini-sized and precise processive die, and the production of press-stamped parts. When the design of a die was completed by means of CAD, wire cut NC data were generated with the aid of a design drawing in the CAD system and then inputed into the wire cut machine, and with the aid of a hole chart which had been made for this purpose, all the data were classified into the categories of CNC milling, jig boring, jig grinding, and machine center, and then developing a program of generating NC data, errors in process were reduced and programming time was shortened. The program was developed by using Autolisp language which was built-in the CAD, and realizing the intergation of designing a die, generating and processing NC data directly by a designer, designing time and machinery processing time were shorted. And the traditionally required working time for design. NC program required 6 days of work becomes 4 days of work by using the developed CAD/CAM system so that the efficiency shows 150% of the reduction working time. The prpgram of the design of the automation a progressive die mold was developed in the PC-Class Autocad system, therefore development expense could be reduced, and the integration of the CAD/CAM of the progressive die mold with the standard DB being built could be realized.

• 한국해양공학회:학술대회논문집
• /
• 한국해양공학회 2002년도 춘계학술대회 논문집
• /
• pp.23-28
• /
• 2002

This paper describes the machining characteristics of the $MoSi_2$ based composites by electric discharge drilling with various tubular electrodes, besides, Hardness characteristics and microstructures of $Nb/MoSi_2$ laminate composites were evaluated from the variation of fabricating conditions such as preparation temperature, applied pressure and pressure holding time. $MoSi_2$ -based composites has been developed in new materials for jet engine of supersonic-speed airplanes and gas turbine for high- temperature generator. Achieving this objective may require new hard materials with high strength and high temperature-resistance. However, With the exception of grinding, traditional machining methods are not applicable to these new materials. Electric discharge machining (EDM) is a thermal process that utilizes a spark discharge to melt a conductive material, the tool electrode being almost non-unloaded, because there is no direct contact between the tool electrode and the workpiece. By combining a nonconducting ceramics with more conducting ceramic it was possible to raise the electrical conductivity. From experimental results, it was found that the lamination from Nb sheet and $MoSi_2$ powder was an excellent strategy to improve hardness characteristics of monolithic $MoSi_2$. However, interfacial reaction products like (Nb, Mo)$SiO_2$ and $Nb_2Si_3$ formed at the interface of $Nb/MoSi_2$ and increased with fabricating temperature. $MoSi_2$ composites which a hole drilling was not possible by the conventional machining process, enhanced the capacity of ED-drilling by adding $NbSi_2$ relative to that of SiC or $ZrO_2$ reinforcements.

• Journal of Periodontal and Implant Science
• /
• 제25권3호
• /
• pp.603-613
• /
• 1995

The purpose of this investigation was to evaluate on the biodegradability, biocompatibility and tissue regenerative capacity of synthetic bioabsorbable membranes in beagle dogs. For animal study, 9 adult beagle dogs were used to examination, on the surgical implantation of membranes and histological analysis. In each animal, the 3rd and 4th premolars of the both sides of the mandible were selected as test teeth. Two types of bioresorbable membranes including "Guidor membrane", "S-membranes" were used to examining for biological activity, and also Gore-tex membranes was used for positive control. Surgically created defects were made in 2 premolars of both sides of the mandible at $3{\times}4mm^2$ in size and tested membranes were implanted in the defected area. A plaque control regimen was instituted with daily tooth brushing with a 0.1% chlorhexidine digluconate during experimental periods. All the experimental animals were sacrificed after 2, 4, and 8 weeks from surgery and undecalcified slides were prepared using the "sawing and grinding" technique described by Donath and Breuner". In biodegradability, all the membranes were started their biodegradation from two weeks after implantation and gradually demolished of their frame morphology from eight weeks. However, demolition of membranes in 8 weeks after implantation was highest in Guidor membranes and followed by S-membranes. Biocompatibilityof two kinds of biodegradable membranes including Guidor and S-mambrane were shown to be well tolerated to the surrounding tissue, and were minimal accumulation of inflammatory cell infiltration around the implanted membranes to compare with Gore-tex membrane. Regeneration of defected alveolar bone was initiated from two weeks of membrane implantation and new bone formation was gradually increased from that time. However, pattern of new bone formation on the defected areas of two kinds of biodegrable membranes was almost similar and quite competitive comparing with Gore-tex membrane. These results implicate that bioresorbable membranes should be highly useful tool for guided tissue regeneration of periodontal defects.

• 구강회복응용과학지
• /
• 제28권1호
• /
• pp.87-101
• /
• 2012

이갈이는 이를 갈거나 악무는 것을 포함하는 부기능적인 행위를 말하며 광범위하게는 주간 및 야간에 나타나는 것을 모두 포함한다. 이갈이의 원인으로는 기본적으로 말초성 요인과 중추성 요인으로 나누어 살펴볼 수 있는데 현재까지의 연구 결과를 종합하여 볼 때 중추성 요인이 주로 작용하는 것으로 알려져 있다. 이러한 이갈이는 교모, 치경부 미세파절, 교근 비대, 교근 및 측두근의 통증, 턱관절의 통증 및 움직임의 제한, 치아 및 수복물 파절, 치수염, 외상성 교합 등을 유발 할 수 있고 특히 이악물기의 경우 협점막 압흔이나 협점막 백선 또는, 혀의 측면에 압흔 등을 유발한다. 이갈이의 정확한 진단을 위해 구강내 장치, 근전도, 수면다원검사 등을 이용하며 미국수면장애학회의 경우 이갈이의 임상 진단 기준을 제시하고 있다. 그러나 아직까지 이갈이의 명확한 원인이 밝혀져 있지 않기 때문에 치료법의 선택은 신중하여야 한다. 이갈이가 중등도 이상이고 임상 증상이나 징후를 유발하는 경우에 이갈이를 관리하기 위한 방법으로는 위험 요인의 조절, 구강내 장치, 보툴리눔 독소 주사, 약물 치료, 바이오피드백 등이 있으며 구강내 장치 요법이 현재로서 가장 합리적인 방법이다. 이갈이 치료와 교근비대에 대한 심미적인 개선을 같이 원하는 환자에서는 보툴리눔 독소 주사 요법이 이용될 수 있다.