• 마이크로전자및패키징학회지
• /
• 제30권4호
• /
• pp.86-90
• /
• 2023

본 연구에서는 패키지에 활용될 수 있는 PVA 고분자 표면의 표면 특성을 흡습성과 경도를 중심으로 향상을 위한 연구를 수행하였다. 접촉각 측정을 통해 표면의 흡습성 특성을 평가하였으며, ASTM_D3363 규격에 준하여 부착력을 평가하였다. 또한, 고분자 표면의 내구성 향상을 위하여, IPL 공정의 파라미터에 따른 경도 및 인성을 연필경도 및 나노인덴테이션 시험으로 특성을 평가하였다. 이와 같은 방법을 통해 0.06N/m의 높은 표면 에너지와 6H의 연필경도, 0.52GPa을 경도를 달성하였다. 이를 통해 고분자 마이크로 패키징에 있어 고분자와 무기물간 이종 소재의 접합 패키징에도 소재들을 견고히 결합하고 악조건 속에서도 작동 환경을 유지하는 접합을 구현하여 습기, 온도 변동 및 부착력, 표면 마모 같은 환경 요인에 대한 고분자 소자의 신뢰성 및 내구성 향상 방법을 제시하였다.

• 한국결정성장학회지
• /
• 제16권3호
• /
• pp.121-126
• /
• 2006

HVOF thermal spray coating of Co-alloy T800 is progressively replacing the classical hard coatings such as chrome plating because of the very toxic $Cr^{6+}$ ion known as carcinogen causing lung cancer. For the study of the possibility of replacing of chrome plating, the wear properties of HVOF Co-alloy T800 coatings are investigated using the reciprocating sliding tester both at room and at an elevated temperature of $1000^{\circ}F\;(538^{\circ}C)$. The possibility as durability improvement coating is studied for the application to the high speed spindles vulnerable to frictional heat and wear. Wear mechanisms at the reciprocating sliding wear test are studied for the application to the systems similar to the sliding test such as high speed spindles. Wear debris and frictional coefficients of T800 coatings both at room and at an elevated temperature of $1000^{\circ}F\;(538^{\circ}C)$ are drastically reduced compared to those of non-coated surface of parent substrate Inconel 718. This study shows that the coating is recommendable for the durability improvement coatings on the surfaces vulnerable to frictional heat. The sliding surfaces are weared by the mixed mechanisms such as oxidative wear, abrasion by the sliding ball slurry erosion by the mixture of solid particles and small drops of the melts and semi-melts of the attrited particles cavitation by the relative motions among the coating, sliding ball, the melts and semi-melts. and corrosive wear. The oxide particles and the melts and semi-melts play roles as solid and liquid lubricant reducing the wear and friction coefficient.

• 대한치과보철학회지
• /
• 제38권3호
• /
• pp.336-347
• /
• 2000

Statement of problem. Luster loss in esthetic anterior ceromer restoration can occur and can be related with rough surface texture. Understanding durability of surface finishing methods like polishing and surface coating have critical importance. Purpose. This study evaluated the effect of tooth brushing and thermal cycling on surface luster of 3 ceromer systems (Artglass, Targis, Sculpture) treated with different surface finishing methods. Material and methods. Seventy-two samples were prepared: 12 for control group Z100, 12 for Artglass, 24 for Targis, and 24 for Sculpture. Half of the Targis and Sculpture were polished according to the manufacturer's recommendation. The rest of the samples were coated with staining and glazing solution for Targis and Sculpture, respectively. All specimens were subjected to 10,000 cycles between $5^{\circ}C\;and\;55^{\circ}C$ with 30 seconds dwell time. Tooth brushing abrasion tests were performed in a customized tooth brushing machine with 500g back and forth for 20,000 cycle. Luster comparisons were based on grading after direct observation, and light reflection area was measured with Image analysis software. Results. All materials showed an decrease in luster grade after thermal cycling and tooth brushing. The post-tooth brushing results revealed that the glazed Sculpture had greater mean luster grade than did any other groups. While, the stained Targis group showed greatest changes after tooth brushing (p < 0.05), polished Targis and Sculpture did not show significant changes. However, glazed Sculpture showed discretely fallen out glaze resin. Conclusion. From the results of this study, all of the ceromer specimens were much glossy than control composite group after tooth brushing. coatings used for Targis and Sculpture had not durability for long term use.

• International Journal of Precision Engineering and Manufacturing-Green Technology
• /
• 제5권5호
• /
• pp.583-591
• /
• 2018

Tool-chip adhesion impacts on cutting performance significantly, especially in finish cutting process. To promote cutting tools' anti-adhesion property, the concave micro-grooves texture (MGT) and convex volcano-like texture (VLT) were fabricated separately on lathe tools' rake faces by laser surface texturing (LST). Various orientations of MGT and different area densities (9% and 48%) and regions (partial and full) of VLT were considered in textured patterns designing. The following orthogonal cutting experiments, machining of aluminum alloy 5038, analyzed tools' performances including cutting force, cutting stability, chip shape, rake face adhesion and abrasion. It indicated that under dry finish cutting conditions, MGT contributed to cutting stability and low cutting forces, meanwhile friction and normal force reduced by around 15% and 10%, respectively with a weak correlation to the grooves' orientation. High density VLT tools, on the other hand, presented an obvious anti-adhesion property. A $5{\mu}m$ reduction of crater wear's depth can be observed on textured rake faces after long length cutting and textured rake faces presented half size of BUE regions comparing to the flat tool, however, once the texture morphologies were filled or worn, the anti-adhesion effect could be invalid. The bearing ratio curve was employed to analysis tool-chip contact and durability of textured surfaces contributing to a better understanding of anti-adhesion and enhanced durability of the textured tools.

• 동력기계공학회지
• /
• 제12권3호
• /
• pp.38-43
• /
• 2008

The usage of electric forklift truck is gradually increasing due to the convenience at conveying and arranging the materials in the industrial field. In this study, the author designed and suggested the optimum driving system and load tester which both of them are the most important part of the forklift truck. The planetary gear is chose to driving system because it makes big power even though the motor size is small. The gear teeth of planetary gear were designed and the designed planetary gear was tested considering the yield strength and the abrasion of gear teeth. The B-Type electric brake which consists of multiple plates and operates with non-magnetic type was connected with a single shaft in the driving system. So, it can be applied at the sudden braking situation which has the torque increment. And it has the compact size and excellent durability Load tester can give the various levels of load to the planetary gear of driving system in the electric forklift truck and it can also measure the levels of the load which were applied. Therefore, we can measure the noise, torque and perform the durability, vibration tests using load tester. It will be economical because many kinds of test can be performed using reasonable priced load tester The driving system of electric forklift truck which has sufficient competitive can be manufactured using our designed planetary gear reducer with reasonable price. The designed load tester can use for checking the performance of other reducers, as well.

• 패션비즈니스
• /
• 제16권6호
• /
• pp.21-35
• /
• 2012

In consideration of the injuries and deaths occurring at manufacturing sites due to the use of inappropriate work clothes or safety devices, this study aims to categorize manufacturing work processes to develop functional work clothes for heavy industries including the automobile, machine and shipbuilding industries in South Korea. Defining the features of the work environments and work postures of these industries provided for a categorization of the work processes which would enable the development of suitable work clothes for each work process' category. The results of the study based on a questionnaire survey are as follows: Work process category 1, including steel panel pressing and auto body assembly, final inspection (in automobile) and inspection (in machine), requires work clothes with upper body and arm mobility and performance to protect from the toxic fume factor. Work process category 2, consisting of welding (in automobile), cutting-and-forming (in machine) and attachment-and-construction (in shipbuilding), requires clothing elasticity, durability and heat and fire resistance. Work process category 3 comprising welding and grinding in the machine and shipbuilding industries, requires work clothes' tear resistance and elasticity, particularly for lateral bending mobility, and work clothes' sleeves' and pants' hemlines with sealed designs to defend against iron filing penetration, as well as incombustible and heat-resistant material performance. Finally, work process category 4, including painting in machine and shipbuilding, requires work clothes with waterproofing, air permeability, thermal performance, elasticity, durability and abrasion resistance.

• 한국재난정보학회 논문집
• /
• 제17권2호
• /
• pp.266-274
• /
• 2021

연구목적: 본 연구는 보행자의 안전 및 다양한 정보를 제공할 수 있는 바닥용 콘크리트 공공 사인 블록의 개발을 목적으로 한다. 연구방법: 이러한 연구목적을 달성하기 위하여 위하여 공공 사인 블록 개발과 관련하여 적용한 단계별 블록 제작 기술을 제시하고, 개발된 콘크리트 공공 사인 블록의 현장적용성을 평가하였다. 연구결과: 본 연구에서 개발된 바닥용 콘크리트 공공 사인 블록은 다양한 형상의 공공 사인의 표현이 가능하고, 제조 단가를 절감할 수 있을 것으로 보인다. 2년간의 사용성 평가결과 균열, 모서리 탈락, 변색, 마모 등의 문제는 발견되지 않아 충분한 내구성을 확보한 것으로 판단된다. 결론: 이러한 연구 결과를 토대로 콘크리트 공공 사인 블록이 기존의 바닥용 공공 사인에 활용되어 오던 스티커, 석재 및 황동판 등의 취약점을 보안할 수 있는 대안으로 활용될 것으로 보이며, 향 후 블록 디자인의 다양화를 도모하여 여러 분야에 적용될 수 있기를 기대한다.

• 한국터널지하공간학회 논문집
• /
• 제21권1호
• /
• pp.49-59
• /
• 2019

본 연구는 로터리드럼커터에 적용된 두 종류의 코니컬 픽커터에 대한 현장시험을 통해 시험 전과 후의 육안조사와 중량감소 및 마모부피를 측정하여 코니컬 픽커터의 내구성을 비교 분석하였다. 육안조사를 통해 슬림 타입 코니컬 픽커터에서만 총 9개의 삽입재 손실이 나타남을 확인하였고 삽입재 보호를 위해 두부의 두께가 중요함을 알 수 있었다. 시험 전과 후의 픽커터의 중량손실과 마모부피는 헤비타입이 슬림타입에 비해 반이하로 작게 나타나 경암반에서 헤비타입이 더 유용함을 확인할 수 있었다. 픽커터의 마모손실을 판단할 때, 중량측정과 마모부피 측정결과의 상호 비교는 재료의 단위중량과 굴착에 의한 스폴링에 의해 차이가 나타날 수 있으므로 주의해야 할 것으로 판단된다.

• 한국가구학회지
• /
• 제25권3호
• /
• pp.223-232
• /
• 2014

To make metalized wood composites of 10 different korean wood species, it was tested by Low temperature melting Bi-Sn alloy injection method at high temperature and high pressure condition. Metalized wood composite of each wood species had light ash color, but still maintained its own natural wood grain and wood figures. It was evaluated on coating properties. Furthermore, it also was check on effect of coating as like a changes of main color, wood grain and wood figures. The results of test were following as; a coating properties as like a cold resistance, heat resistance, acid resistance, alkali resistance, durability of abrasion, and cross-cut test was proper on the conditions of the KS standard. And, In aspect of color changes, the metalized wood composites of 10 different korean wood species had a light ash color, but still maintained its own natural wood grain and wood figures. Also, the more weight per gain of alloy is, the more grey background of metalized wood composite is.

• 열처리공학회지
• /
• 제33권1호
• /
• pp.25-32
• /
• 2020

In this study, the tribology of laser patterned DLC thin film was studied. DLC thin films were coated by RF-PECVD to improve the durability of tungsten carbide (WC) materials. DLC thin films have high hardness and low friction characteristics. Dot and line patterning was processed on the surface of DLC thin film with femtosecond laser, and the coefficient of friction was improved. As a result of ball on disk abrasion test, the hardness and friction coefficient of DLC thin films were much better than that of WC material. The friction coefficient of DLC thin film with dot patterning and line patterning showed better results. The excellent performance of the laser patterned DLC coating is appeared to reduce the coefficient of friction due to the reduction of surface contact area.