• 제목/요약/키워드: part-time wear

검색결과 90건 처리시간 0.034초

Thixoforging을 이용한 중공형 금속복합재료 부품의 성형공정에 있어서 결함예측 (Defect Prediction in Part Fabrication Process of Metal Matrix Composites by Thixoforging Process)

  • 윤성원;김병민;강충길
    • 소성∙가공
    • /
    • 제12권2호
    • /
    • pp.102-109
    • /
    • 2003
  • In the manufacturing process of metal matrix composites parts, thixoforging is one of the most effective forming processes. The major purpose of the current study is to provide the proper conditions such as the die shape, the forging velocity, the forging time, the forging pressure and reinforcement injection velocity and pressure on various defects in thixoforged cylinder liner, filling tests were performed by MAGMA S/W. In order to evaluate the effectiveness of the calculated conditions which is given by computer aided engineering, A357, A380 and SiC$_{p}$/A380 cylind~5$mu extrm{m}$r liner were fabricated under the calculated conditions. SiC$_{p}$/A380 composite billets were fabricated by both the mechanical stirring and electrical magnetic stirring process. Incase fo SiC$_{p}$/A380 composite cylinder liner, reinforcement distribution and effect of reinforcement(SiC$_{p}$) content(10~20 vol. %)and size(5.5~14${\mu}{\textrm}{m}$) on the mechanical properties were investigatedstigated.

고속가공을 이용한 고경도 코어부의 가공성 향상기술 (Improvement Technique of Machinibility in machining high-hardened Core Part through High Speed machining)

  • 임유업;김정석;강명창;박희영
    • 대한기계학회:학술대회논문집
    • /
    • 대한기계학회 2001년도 춘계학술대회논문집C
    • /
    • pp.88-93
    • /
    • 2001
  • As the development of High Speed Machining, It is applied in many fields of manufacturing. Among them is to manufacture die and mold. But it still remains as a hard-to-work to apply it in machining pre-hardened materials such as hardened QRO90. It also difficult to machine new materials because there is no machining date of them. Therefore, in this study, we are trying to improve the machinability of new material, QRO90 by applying various cutting conditions, and selecting the best condition which not only reduce the machining time but improve the quality of die and mold made of QRO90 material.

  • PDF

Planetary Milling과 Side Milling에 의한 Worm 가공 특성 비교 (Machinability Comparison of Planetary Milling and Side Milling for Worm Machining)

  • 이민환;권태웅;강동배;김화영;안중환
    • 한국정밀공학회지
    • /
    • 제23권10호
    • /
    • pp.44-51
    • /
    • 2006
  • According to global trend of the expanding need of high-quality automobiles, the usage of small precise worm consisting of gearing part for motors to actuate convenience modules has increased rapidly. Precision of those worms has very sensitive characteristic to motor performance and noise. Forming process has been generally used to manufacture worms because of its mass productivity. However, it has problems such as deformation due to residual stress and wear of dies. Planetary milling and side milling are among alternatives using cutting tools. To overcome those problems the two machining methods have some contrast features in the sense of tool numbers and cutting mechanism. In this paper, machinability of both methods was compared in terms of cutting force, precision and cycle time.

중국의 둥근 깃 전래에 관한 소고-《오백도적귀의도》를 중심으로- (A Study on Chinese Round Neckline-In Reference to The Five Hundred Thieves to Become Buddhist Monks)

  • 김영재
    • 복식
    • /
    • 제36권
    • /
    • pp.97-107
    • /
    • 1998
  • This is a studying on Chinese round neckline. Chinese round neckline is originate from Kucha and Bei-Wei. After round neckling was flown into Chinese, it had been worn in all classes including Emperor as well as common people. Women-talents and court ladis-likes to wear it too, especially Tang Dynasty. This study is describe processes of changes and characters of Chinese. The first inflow time of round neckline into China was assumed in Bei-Wei. In Bei-Chi, it changed right lapel and it fastened by a button. In Chinese each dynasty, Round neckline had been worn in Emperor, common people talents and a part of court ladies.

  • PDF

레이저클래딩 공정 모니터링 시스템 개발 (I) - 최적공정변수 추출 (Development of A Laser Cladding Process Monitoring System (I) -Extraction of optimal process variables)

  • 오기석;윤길상;조명우;김문기
    • 한국정밀공학회:학술대회논문집
    • /
    • 한국정밀공학회 2000년도 추계학술대회 논문집
    • /
    • pp.89-92
    • /
    • 2000
  • Laser claddmg 1s thc deposition of material on the surface of a part or workpiece. Cladding of metals produces a 100% dense metallurgically-bonded coating with minimal dilution for enhanced corrosion, abrasion and wear resistance. Despite of minimal heat Input and reduced processing time, cladding quality 1s affected by various process condition such as laser power and feed rate. Therefore, it is necessary to develop the momtoring and control methods of laser cladding process for the best cladding quality. In this paper, laser cladding monitoring system using CCD camera for measuring cladding pool shape, and photo-diode sensor for detecting optical signal emitted from the cladding front is introduced The variables extracted using this system can be apphed to control the laser cladding system to achieve the best claddmg results..

  • PDF

WS$_2$ 고체윤활제의 양산 및 적용 (Mass-production of WS$_2$ Solid Lubricant and Its applications)

  • 신동우;최인혁;윤대현;김경도
    • 한국윤활학회:학술대회논문집
    • /
    • 한국윤활학회 1998년도 제28회 추계학술대회
    • /
    • pp.221-226
    • /
    • 1998
  • The processing conditions for the mass production of platelet WS$_2$ lubricant powder were optimized. The mixture of tungsten and sulfur powders was sealed in a vacuum of 10$^{-3}$ torr and heat-treated at 850$\circ$C for 2 h. The internal pressure of reaction chamber was maintained at certain level by controlling the release valve automatically. The reaction product was the platelet WS$_2$ powder with an average size of 15 $\mu$m. The synthesized WS$_2$ powder was then coated on the wiper-blade of automobiles and the commercial deep-grooved ball bearing using wet and dry coating methods, respectively. High lubricity and wear resistance of wet coated wiper-blade were confirmed by the life test of 70,000 cycles. The life-time of the ball bearing assembled after WS$_2$ coating onto each part increased 50 times compared to the non-coated ball bearing.

  • PDF

핫스템핑 부품의 전단가공에서 전단 하중의 감소 및 트리밍 금형 수명 향상을 위한 국부 연화 방법 (A Local Softening Method for Reducing Die Load and Increasing Service Life in Trimming of Hot Stamped Part)

  • 최홍석;임우승;강충길;김병민
    • 소성∙가공
    • /
    • 제20권6호
    • /
    • pp.427-431
    • /
    • 2011
  • In general, hot stamped component is trimmed by costly and time consuming laser cutting when the material strength is over 1,500MPa. The aim of this work was to demonstrate that the trimming die life is improved and the trimming load is decreased by lowering the strength of the region to be trimmed. The model employed in this study was a hat shape, similar to the cross section of many hot stamped products. FE-analysis of hot stamping process was performed to evaluate the effect of tool shape on cooling rate at the area to be trimmed. The best tool shape was thus identified, which created slower cooling and lower hardness at the region to be trimmed. The wear at the cutting tool edge was also reduced.

현대여성(現代女性)의 의복의식(衣服意識)에 관한 조사(調査) 연구(硏究) - 서울 지역(地域)의 양복(洋服) 착용자(着用者)를 중심(中心)으로 -

  • 이희명
    • 복식
    • /
    • 제2권
    • /
    • pp.73-88
    • /
    • 1978
  • This article is an attempt to explain, at least in part, the contemporary Korean women's consciousness of Western Dreasses. As time changes, the role of clothing undergoes varisous transitions, while values and ways of life are constantly in change. It is, therefore, proper and appropriate to recognize as among the major aspects of social psychology such phenomenon as interests, understanding of clothing, the choice of a dress, and attitudes toward clothing, etc. The purpose of this study is to discover problems concerning and their clothing and their solutions, by means of a surveying approach. The method of research used is based upon questionares distributed to parents of first-year pupils in elementary schools and to female clerks working in offices, covering the period from August through October, 1976. The number of the questionares distrubuted totalled 600, and 526 were returned to the research to be utilized for analysis. The contents of the survey included such things as values concerning clothing, kinds of clothing and their practical use, the selection of clothing and the method of purchase, fashions, etc. The classification of aquisition are self-made clothing, clothing made to order and ready-made materials. It is composed of 25 items, including affirmative reasons as well as negative ones. The processing of the material returned was made by using the computer, and based upon classifications such as ages, monthly income, occupations; thus diagraming the result in percentages. The conclusion made and the improvements proposed are as follows: 1. The values of clothing were placed on the expression of the wearer's personality (32.7) and on eauty(28. 6%). The lower age group places is stress upon the expression of personality, while the higher age group stresses beauty. About 50% of wearers are contented with their clothing, their clothing, the rest of whom them indicating their dissatisfaction with what they wear. As to designs at the time of selection, about 46% indicated their preference of personal expression, 31.8% on usefulness. In selecting material, practicality is emphasized; in selecting patterns, single color is preferred. In short, personal expression and esthetic values are primary, with consideration of practicality in mind. 2. The classification of clothing according to their uses indicates the highest numbers in normal wear (home wears) and clothings to be worn outside home. As to evening dresses, (party dress) only one or two articles were checked by many, and no such article was clamed to be possessed by most. The highest ratio of wearing was shown in the case of home wear (47.3%) and clothing to be worn outside the home, which is 55.8%. The budget for one article of clothing was greatest in the case of home wear, and clothing worn outside the home. Many used both kinds of articles for the same purpose. It is desirable, therefore, that the kinds of clothing should be varied according to the purpose for which they are worn, and that clothing appropriate for that purpose should be worn. 3. The motivation for purchasing clothing was highly chosen in the item of seasonal change, which was 55.7%; Clothing deliberately made was indicated by 45.2%. In the mothods of purchasing clothing, clothing made to order and ready-made was indicated by 44.4%, which is the highest; Clothing made to order was 25.4%, and self-sewing was 1.1%, which is the lowest. (1) In the case of self-sewing, "I like it but it is very hard," was checked by 43.6%; "It is so difficult that I cannot wear such clothing" was checked by 13.3%. From these, we can conclude that the questionees are willing to make clothing by themselves, but techniques involved in sewing and at her problems involved in the skill are complicated but when those problems are eliminated there is a possibility for practice. The response checked by questionees concerning the self-sewing was, "It's economical", which is a clear indication that many questionees are positive for self-sewing. It is generally believed that ready-made clothing is cheaper, but it is not necessarily so. In consideration of the quality of clothing, self-sewing is a necessity, and it is desirable that it should be encouraged. (3) Problems involved in ready-made clothing, such as designs, skills, size (fitting) should be eliminated. When these problems are scientifically gotten rid of, it is possible that affirmative returns will be expected. Affirmative responses such as "Ready-made clothing is economical," "You can select there on the spot," are good signs that many women expect to wear ready-made clothing. It is in this sense that the prospect for ready-made clothing is brighter when much development for ready-made clothing is on the way. 4. Much concern for fashion are checked in such item of questions as "Fashionable clothing in the show window," "Clothes worn by women." The first item was checked by 50.1 %, and the second was checked by 48.6%. The reason for following fashion is "Because many people wear them," which was indicated by 30.4%. The reason for not following fashion is "It is too expensive," which was checked by 29.6%. The 26.2% of the answers indicated that "Fashionable clothing is devoid of personality," The influences of fashion over the development of fashion over the development of clothing are two-fold: Esthetic and active. It is not to be deniable that people follow fashion more or less. 1978.9>

  • PDF

굴삭기 유압 주행시스템의 복합유성기어 시스템 설계개선 연구 (Design Improvement for a Planetary Gear System in Hydraulic Drive System)

  • 신유인;윤찬헌;한성길;박성규;송철기
    • 한국정밀공학회지
    • /
    • 제33권10호
    • /
    • pp.851-856
    • /
    • 2016
  • Planetary gear systems have several advantages over traditional gearboxes with parallel axis gear shafts. The planetary gearbox arrangement also creates greater stability due to the even distribution of mass and increased rotational stiffness. However, gears in planetary gear systems occasionally have a short-life due to wear and breakage by repetitive load during operation time. In this study, we evaluated variables of the strength design for each part and conducted structural analysis of seven cases of the planetary gear system. The result of structural analysis was applied to shape optimization method and obtaining the weight lightening designed value. Subsequently, the planetary gear system was performed to ensure the durability of gears during operation time with miner's rule.

20대 여성의 신발종류에 따른 족저압 영역별 비교 연구 (A comparison study for mask plantar pressure measures to the difference of shoes in 20 female)

  • 김용재;지진구;김정태;홍준희;이중숙;이훈식;박승범
    • 한국운동역학회지
    • /
    • 제14권3호
    • /
    • pp.83-98
    • /
    • 2004
  • The purpose of this study was to investigate the test-retest of plantar pressures using the F-Scan system over speeds and plantar regions. 6 healthy female subjects in 20's were recruited for the study. Plantar pressure measurements during locomotor activities can provide information concerning foot function, particularly if the timing and magnitude of the loading profile can be related to the location of specific foot structures such as the metatarsal heads. The Tekscan F-Scan system consists of a flexible, 0.18mm thick sole-shape having 1260 pressure sensors, the sensor insole was trimmed to fit the subjects' right. left shoes - sneakers shoes & dress shoes. It was calibrated by the known weight of the test subject standing on one foot. The Tekscan measurements show the insole pressure distribution as a function of the time. This finding has important implications for the development of plantar pressure test protocols where the function of the forefoot is important. According to the result of analysis it is as follows 1) Center of force trajectory in women's dress shoes display direct movement, compare with center of force trajectory in Sneaker shoes displays a little bit curved slow pronation movement. Sneaker shoes in forefoot part display very quick supination movement, therefore, this shoes effects negative effectiveness for ankle's stability Considering center of force trajectory analyzing the more center of force close straight line, the more movement can be quick movement for locomotion. For foot pressure distribution, center of force trajectory in locomotion is better to curved trajectory with pronation movement. So sneaker shoes style is good shoes considering center of pressure distribution trajectory compare with women's dress shoes. 2) Women's dress shoes increased peak pressure in medial, this is effected by high hill's height. The more increased women's dress shoes's height, the more women's peak pressure will increase, pronation can increase compare with before. Supination movement increase, this focused pressure in lateral, also, supination increased more. If the supination movement increased, foot pressure focused in lateral, therefore, it is appeared force distribution in gait direction. This is bad movement in foot's stability. 3) Women's dress shoes in landing phase displayed a long time, this is when women's dress shoes wear, gait movement is unbalance, so, landing phase displayed a long time. For compensation in gait, swing phase quick movement. 4) Women's dress shoes displayed peak pressure distribution in lateral of rearfoot part, Sneakers shoes displayed peak pressure distribution in medial of forefoot part. Its results has good impact absorption compare with women's dress shoes. In forefoot part, sneakers shoes has good propulsive force compare with women's dress shoes.