• 제목/요약/키워드: Shrinkage Ring

검색결과 55건 처리시간 0.024초

Properties of Bentwood for Esthetic Designing by Microwave and Ammonia Solution Treatment

  • Lee, Won-Hee;Bae, Hyun-Mi
    • 한국가구학회지
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    • 제18권4호
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    • pp.275-281
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    • 2007
  • This study was carried out to know bending process property of bentwood by treatment methods such as microwave and ammonia solution treatment. Bentwood processing was operated on bending-jig form with 60mm and 100mm radius of curvature (ROC). The species was used to Korean red pine (Pinus densiflora). No significant difference was shown in bentwood processing method on ROC. In treatment method, ammonia solution treatment for bentwood was better in dimensional stability and working ability than that of microwave treatment. However, bentwood stress was reduced with ammonia solution treatment. Color of bentwood surface appearance has a dark tendency in ammonia solution treatment. But it seems to beautiful effect of apparent annual ring is rising esthetically by ammonia solution treatment. To utilize wood as a exterior material for living amenity, it has to be closely examined from various angles including surface property, degree of swelling and shrinkage, drying state, retaining strength, durability, safety, and insect damage.

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앨터네이터 로터폴의 단조가공에서 공전개선과 금형제작에 관한 연구 (A Study on the Manufacturing of Die and Improvement of Process in Fiorging Work of Alternator Rotor Pole)

  • 김세환
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 1997년도 춘계학술대회 논문집
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    • pp.54-61
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    • 1997
  • Furthermore the rothor pole, with a solid type, manufactured by cold forging process at present should dmploy 3 press lines which consist of total 7 processes. Since A.S.B. treatment is prerequisite for the press line, the 3 times of A.S.B. treatment requires a long lead time, with little contribution to the reduction in cost. The author has investigated, through this researach, the possibility of a new forging method for a rotor pole production with (1) 2 pass instead of 3 press lines (2) only one A.S.B. treatment instead of 3 ones (3) solid type instead of sectional type, and (4) improvment of material property during process using a modified forging process and a specially designed die.

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단일보강링 원통형 금형의 최적 설계용 CAD 프로그램 개발 (Development of a CAD program for optimal design of a cylinderical die with one stress-ring)

  • 신중호;손주리;류갑상
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1988년도 한국자동제어학술회의논문집(국내학술편); 한국전력공사연수원, 서울; 21-22 Oct. 1988
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    • pp.556-561
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    • 1988
  • Shrink-rings (Stress-rings) are used in the fabrication of dies for cold forming and powder compaction processes to increase the allowable pressures for a given die material. Optimum procedures are to minimize a die thickness under the conditions that the stress distributions in the die and stress-rings utilize fully the strength available in each of the die elements. This paper proposes a new approach, where the maximum allowable shrinking pressures are calculated on shrinkage plans in the radial direction and the fractional shrinking pressures below the maximum allowable pressures are used as the design values. Two criteria for the optimal die design are used: Maximum shear stress limit for one-piece dies and zero tensile stress limit for combined dies. A computer program, DIECOM, is developed for illustrating the computer-aided design procedures. Finally, examples for each case are presented in this paper.

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치아 와동의 복합레진 수복시 음향방출의 시간적 발생 특성 (Time-Based Characteristics of Acoustic Emission During Dental Composite Restoration)

  • 구자국;최낙삼
    • 대한기계학회논문집A
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    • 제35권2호
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    • pp.169-174
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    • 2011
  • 제 1 급 와동이 모사된 비관통형 치아 시편에 수복된 복합레진의 중합 수축시 발생하는 AE 신호를 실시간으로 검출한 후 이를 분석하였다. 시간대별 발생 분포를 살펴보면, 광조사 초기에 중합 수축이 급격히 진행되는 제 I 구간에서 AE event 가 많이 관찰되었다. 제 I구간 후 AE event 발생 빈도가 낮아져 AE 가 별로 관찰되지 않은 제II구간이 있었는데, AE 신호의 발생이 적은 PMMA 는 치아에 비해 구간이 길었으며 AE 검출이 잦았던 스테인리스스틸 모형은 제 II 구간이 짧았다. AE 활성도를 나타내는 구간 특성은 수복재와 와동의 계면부에서 일어나는 균열의 발생빈도를 나타내는 것으로 사료되며 젤화점 직후의 제I 구간에서 AE 가 집중적으로 관측되는 바, 수복재와 와동 사이의 갭 형성은 바로 젤화점 직후에 만들어졌음을 가리킨다. 신호의 최대 진폭은 25-45dB 이었고 1 차 중심 주파수는 100-200kHz 와 240-400kHz 영역의 신호들이 발생하였으며 이는 레진이나 접착층의 파괴에 해당하였다.

치과용 합금 주조 시 주조링의 계류시간에 따른 보철물의 변연 적합도 실험에 관한 연구 (An Experimental Study on Margin Consistency of Prosthesis According to the Continued Time of Casting-Ring in the course of the Casting of Dental Alloy)

  • 황성식;이상혁
    • 대한치과기공학회지
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    • 제23권2호
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    • pp.179-188
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    • 2002
  • With regard to the manufacture of dental prosthesis, all the dental mechanism is of vital significance at the aspect of activating its function by fixing the prosthesis to Patient's oral cavity. However, if there we will take our immediate action without the discretion about its process none the less for the importance of dental mechanism, then we might have a serious problem. Accordingly, there need to pay attention to the dilatability makes up for the shrinkage state occurring by the feature of metal materials and manufacturing process which appeared in the process of dental mechanism, which eventually is expected to playa very important role in casting a dental prosthesis appropriate to one's oral tissue. This study was designed to take into account of the effects on margin consistency of prosthesis according to the continued time of casting-ring in the course of the casting of dental alloy. For this, the researcher made an experiment on the casting of dental alloy, its dilatability, and the change of phase. The results of this study were as follows: First, the researcher could see that the sample which was cast under the condition of $650^{\circ}C/20$ Minutes(the continued time) was far superior to others at the aspect of margin consistency. Second, according to the measurement of expansion coefficient by Dilatometer, the researcher perceived the fact that the expansion-coefficient showed a maximum of $37.1{\mu}m$ considering the sample's length which was cast with ordinary temperature under the condition of $650^{\circ}C/20$ Minutes. Third, from the result of X-ray diffraction under the condition of $650^{\circ}C/20$ Minutes(the continued time), the researcher could find that there's no difference between the change of phase and its intensity. As mentioned above, the researcher could ascertain the fact that its contraction don't give rise to the change of phase.

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잣나무 소경재의 재질평가를 통한 실내장식용재 개발 (A Development of Interior Decoration Timber with Pinus koraiensis Small Diameter Logs)

  • 박병호;김남훈
    • Journal of Forest and Environmental Science
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    • 제28권4호
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    • pp.268-277
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    • 2012
  • Among the domestic softwoods, technical value of Pinus koraiensis small diameter logs which have comparatively low applicability was evaluated and sensitive characteristics and physical characteristics were investigated and analyzed for examining if it can be utilized as the interior decoration material. For the sensitive characteristics of Pinus koraiensis, wood figure, wood grain, wood color and odor were evaluated and for the physical characteristics, growth-ring width and latewood percentage, abrasion, density, shrinkage, swelling, absorption, roughness and hardness were evaluated. Then, the possibility to be developed as the interior decoration material was found. As the result of evaluating sensitive characteristics and physical characteristics of domestic Pinus koraiensis, wood figure, wood grain, color and scent clearly were judged to have excellent visual factor as the interior decoration material. And, physical characteristics were also judged to be excellent, so it is judged to be developed as the interior decoration material. Therefore, as the result of various forms of design pattern with domestic Pinus koraiensis small diameter logs, several patterns of interior decoration can be developed by characteristics of each side and colors of heartwood and sapwood. And, in the future, it can be applied to furniture design or interior decoration material for the proper use. Especially, it is considered to contribute to wood applying industry through the study on the quality of domestic small diameter logs which have low applicability.

Al6082의 가공한계를 고려한 냉간단조 공정설계 (Multistage Cold Forging Process Design of Al6082 Considering Forming Limit)

  • 안규희;강종훈;허수진;신태수;조해용
    • 한국기계가공학회지
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    • 제19권9호
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    • pp.93-99
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    • 2020
  • Recently, as the weight reduction of vehicles has been actively progressed, parts developed using aluminum 60XX series from existing steel materials are increasing. In this paper, the bushing used for the front frame rail, which is one of the parts for fixing engines and other parts in automobiles, was changed to an aluminum material of the Al60XX series, and it was intended to be produced by applying of cold forging method. The bushing is a part that secures the engine frame, and in order to produce it by cold forging, the molding limit is predicted through process design, and a multi-stage process is designed through finite element analysis. In addition, in order to verify the feasibility of the designed forging process, the limits of the multi-step process were verified based on the Cockcroft Latham theory, and the crack and overlap of the actual forging work were predicted and improved.

Utilization of Waste Glass Micro-particles in Producing Self-Consolidating Concrete Mixtures

  • Sharifi, Yasser;Afshoon, Iman;Firoozjaei, Zeinab;Momeni, Amin
    • International Journal of Concrete Structures and Materials
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    • 제10권3호
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    • pp.337-353
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    • 2016
  • The successful completion of the present research would be achieved using ground waste glass (GWG) microparticles in self-consolidating concrete (SCC). Here, the influences of GWG microparticles as cementing material on mechanical and durability response properties of SCC are investigated. The aim of this study is to investigate the hardened mechanical properties, percentage of water absorption, free drying shrinkage, unit weight and Alkali Silica Reaction (ASR) of binary blended concrete with partial replacement of cement by 5, 10, 15, 20, 25 and 30 wt% of GWG microparticles. Besides, slump flow, V-funnel, L-box, J-ring, GTM screen stability, visual stability index (VSI), setting time and air content tests were also performed as workability of fresh concrete indicators. The results show that the workability of fresh concrete was increased by increasing the content of GWG microparticles. The results showed that using GWG microparticles up to maximum replacement of 15 % produces concrete with improved hardened strengths. From the results, when the amount of GWG increased there was a gradual decrease in ASR expansion. Results showed that it is possible to successfully produce SCC with GWG as cementing material in terms of workability, durability and hardened properties.

산불 피해 소나무재의 해부 및 물리학적 특성 (Anatomical and Physical Characteristics of Pinus Densiflora Wood Damaged by Forest Fire)

  • 황원중;권구중;김남훈
    • Journal of the Korean Wood Science and Technology
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    • 제31권4호
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    • pp.1-7
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    • 2003
  • 본 연구에서는 산불 피해를 입은 소나무재의 유효 활용을 위한 기초자료를 얻고자 해부 및 물리학적 특성을 조사하였다. 산불 피해재의 수지구, 에피델리얼세포와 방사유세포내에는 건전재와 달리 과립모양의 물질이 많이 존재하였으며, 그 외의 목부 조직구조는 정상재와 거의 차이가 없었다. 건전재와 비교하여, 산불 피해재는 상대결정화도가 다소 높았으며, 생재함수율과 접선 및 방사단면 흡수량은 다소 낮게 나타났다. 수축율 및 팽윤율과 기본밀도는 정상재와 거의 유사한 값을 보여주었다.

알콕시 실란계 석재 보존 및 강화제 개발 (Development of Alkoxysilane Mixed Solution as Stone Preservation and Consolidation Materials)

  • 김은경;박성용;조현동;원종옥;도진영;김사덕
    • 보존과학회지
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    • 제21권
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    • pp.21-32
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    • 2007
  • 젤 반응을 통해 약화된 석재 조직에 응집력을 주어 석재를 강화시킬 뿐 아니라, 물의 침투로 인하여 발생될 수 있는 석재의 풍화나 손상을 방지하기 위해 소수성 도입 및 2차 박리를 막기 위해 에폭시 접착제와 상호작용이 있는 기능성 석재강화제를 개발하였다. 또한 상업적으로 사용되고 있는 알콕시실란계 강화제의 특성을 비교 연구하였다. 상업화된 알콕시 실란계 석재 강화제의 기본 물질인 tetraethoxysilane에 발수성 기능을 갖고 있는 methy tri silane, ethyl tri silane 그리고 에폭시기를 갖고 있는 (3-glycidyloxypropyl)trimethoxysilane를 도입하여 기능성 석재 강화제를 개발하였다. 사암과 화강암에 처리하였고, 젤 형성 시간, 발수성 및 기공도 변화, FT-IR 분석 및 SEM등을 통해 상업화된 석재 강화제와 비교하여, 응용가능성을 확인하였다.

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