• Title/Summary/Keyword: Multi-tool

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Experimental Study on Multi-Stage Cold Forging for an Outer Race of a CV Joint (등속조인트용 외륜의 다단 냉간 단조공정에 관한 실험적 연구)

  • Kang, B.S.;Ku, T.W.
    • Transactions of Materials Processing
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    • v.23 no.4
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    • pp.221-230
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    • 2014
  • This study deals with a series of experimental investigations on multi-stage cold forging of an outer race used for a constant velocity (CV) joint with six inner ball grooves. The multi-stage cold forging, which consists of forward extrusion, upsetting, backward extrusion, and combined sizing-necking including ironing, was used to produce a prototype of the outer race. The cold forging tools such as forging punches and dies required in this multi-stage cold forging were also designed and fabricated. For the combined sizing-necking, especially, the longitudinally six-segmentallized punches were developed to easily eject from the necked inner groove of the outer race with consideration of the operating mechanism. Spheroidized SCr420H billet was used in the experimental study. To verify the suitability of the proposed process, the obtained parts were obtained from each forging operation, and the geometries were compared with the target dimensions. It was confirmed that the outer race with six inner ball grooves was well forged by adopting the proposed multi-stage cold forging, and the dimensional accuracy of the forged outer race matched well with the requirements.

Development of Design System for Multi-Stage Gear Drives Using Simulated Annealing Algorithm (시뮬레이티드 어닐링을 이용한 다단 치차장치의 설계 시스템 개발)

  • 정태형
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 1999.10a
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    • pp.464-469
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    • 1999
  • Recently, the need for designing multi-stage gear drive has been increased as the hear drives are used more in the applications with high-speed and small volume. The design of multi-stage gear drives includes not only dimensional design but also configuration design of various machine elements. Until now, however, the researches on the design of gear drives are mainly focused on the single-stage gear drives and the design practices for multi-stage gear drives, especially in configuration design activity, mainly depend on the experiences and 'sense' of the designer by trial and error. We propose a design algorithm to automate the dimension design and the configuration design of multi-stage gear drives. The design process consists of four steps. The number of stage should be determined in the first step. In second step, the gear ratios of each reduction stage are determined using random search, and the ratios are basic input for the dimension design of gears, which is performed by the exhaustive search in third step. The designs of gears are guaranteed by the pitting resistance and bending strength rating practices by AGMA rating formulas. In configuration design, the positions of gears are determined to minimize the volume of gearbox using simulated annealing algorithm. The effectiveness of the algorithm is assured by the design example of a 4-stage gear drive.

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Development of Expert System for Burr Formation Prediction in Face Milling (II) - In Milling Multi Featured workpiece with Multi (밀링가공시 버 형성 예측을 위한 전문가 시스템 개발 (II) - 복잡한 형상의 피삭재와 다중경로에 의한 밀링가공시)

  • 고성림;김영진;장재은;이장범;김지환
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.12
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    • pp.25-33
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    • 2003
  • A burr has been defined as undesirable projection of material formed as a result of plastic flow from a cutting or shearing operation. It is unavoidable in all kinds of machining operation. As a result, burr makes troubles on manufacturing process due to deburring cost, quality of products and productivity. In this study, the primary interest is about exit burr. The burr formation mechanism in each type of burr is classified. Data bases are developed to predict burr formation result. In the milling operation, we develop an algorithm to analyze the burr formation mechanism by the geometrical analysis on the multi featured workpiece with multi cutting path. The algorithm includes three steps, i. e., the feature identification, the cutting condition identification, and the analysis on exit burr formation. We can predict which portion of workpiece would have the exit burr in advance so that we can manage to find a way to minimize the exit burr formation in an actual cutting. Also, this algorithm can be implemented in a commercial CAM package so that we can simulate the NC code to review the burr formation in advance.

Generation and Preliminary Design of Compound Multi-Stage Gear Drive Mechanisms (복합 다단 기어장치 메커니즘의 생성 및 초기설계)

  • Chong Tae-Hyong;Kim Jang-Soo;Park Seung-Hyun
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.14 no.4
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    • pp.41-48
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    • 2005
  • In recent years, the need for multi-stage gear drives which highly reduce output speed has been increased. However, the design of multi-stage gear drives has been carried out by a limited number of experts. The consideration for the direction of input and output axes also makes their design very difficult. The purpose of this study is to develop an algorithm for automatically generating complex multi-stage gear drives and to implement a design supporting system for multi-stage gear drives. There are 4 stages in the proposed algorithm, and major design parameters, such as the direction of input and output axes, reduction ratio, etc. are set up in the first stage. In the second stage, all mechanisms are generated, and various rules are applied to select feasible mechanisms. In the third stage, the gear ratio of each stage is divided from total gear ratio. Next, the specifications of gears for feasible mechanisms are calculated and their bending strength and surface durability are estimated. In the forth stage, appraised indexes are calculated and provided to support the estimation of the generated gear drives.

A Survey on the Present status of the Multi-purpose Auditorium using the Advance Building Quality Evaluation Technique(ABQET): Focused on Elementary, Middle and High Schools in Gumi City (발전된 건물의 성능평가기법(ABQET)을 이용한 다목적 강당의 현황과 실태에 관한 조사연구 - 구미시를 중심으로 -)

  • Kim, Kyung-Tae;Song, Dong-Hun;Lee, Seung-Jun;Shin, Hyun-Ik
    • Journal of the Korean Institute of Educational Facilities
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    • v.24 no.4
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    • pp.3-14
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    • 2017
  • Since the education law was changed in 1997, schools for K-12 education are required to build a multi-purpose auditorium which accommodates auditorium and a gymnasium functions. Evaluation of the present status of multi-purpose auditoriums will provide a clear direction for improvements in planning and design stages. The purpose of this research identifies the current status and major drawbacks of the multi-purpose auditorium through applying a performance evaluation tool kit called the Advanced Building Quality Evaluation Techniques(ABQET) and Graphic Analysis of Quality Quotient (GAQQ). In addition, the research will provide future foundations for planning and design methods for a multi-purpose auditorium.

Visualization for Integrated Analysis of Multi-Omics Data by Harmful Substances Exposed to Human (인체 유래 환경유해물질 노출에 따른 멀티 오믹스 데이터 통합 분석 가시화 시스템)

  • Shin, Ga-Hee;Hong, Ji-Man;Park, Seo-Woo;Kang, Byeong-Chul;Lee, Bong-Mun
    • Journal of Korea Multimedia Society
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    • v.25 no.2
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    • pp.363-373
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    • 2022
  • Multi-omics data is difficult to interpret due to the heterogeneity of information by the volume of data, the complexity of characteristics of each data, and the diversity of omics platforms. There is not yet a system for interpreting to visualize research data on environmental diseases concerning environmental harmful substances. We provide MEE, a web-based visualization tool, to comprehensively explore the complexity of data due to the interconnected characteristics of high-dimensional data sets according to exposure to various environmental harmful substances. MEE visualizes omics data of correlation between omics data, subjects and samples by keyword searches of meta data, multi-omics data, and harmful substances. MEE has been demonstrated the versatility by two examples. We confirmed the correlation between smoking and asthma with RNA-seq and Methylation-Chip data, it was visualized that genes (P HACTR3, PXDN, QZMB, SOCS3 etc.) significantly related to autoimmune or inflammatory diseases. To visualize the correlation between atopic dermatitis and heavy metals, we selected 32 genes related immune response by integrated analysis of multi-omics data. However, it did not show a significant correlation between mercury in blood and atopic dermatitis. In the future, should continuously collect an appropriate level of multi-omics data in MEE system, will obtain data to analyze environmental substances and diseases.

Micro cutting process technology for micro molds parts (마이크로 금형 부품을 위한 마이크로 절삭가공 기술)

  • Ha, Seok-Jae;Park, Jeong-Yeon;Kim, Gun-Hee;Yoon, Gil-Sang
    • Design & Manufacturing
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    • v.13 no.1
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    • pp.5-12
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    • 2019
  • In this paper, we studied the micro tool deflection, micro cutting with low temperature, and deformation of micro ribs caused by cutting forces. First, we performed an integrated machining error compensation method based on captured images of tool deflection shapes in micro cutting process. In micro cutting process, micro tool deflection generates very serious problems in contrast to macro tool deflection. To get the real images of micro tool deflection, it is possible to estimate tool deflection in cutting conditions modeled and to compensate for machining errors using an iterative algorithm correcting tool path. Second, in macro cutting fields, the cryogenic cutting process has been applied to cut the refractory metal but, the serious problem may be generated in micro cutting fields by the cryogenic environment. However, if the proper low temperature is applied to micro cutting area, the cooling effect of cutting heat is expected. Such effect can make the reduction of tool wear and burr formation. For verifying this passibility, the micro cutting experiment at low temperature was performed and SEM images were analyzed. Third, the micro pattern was deformed by the cutting forces and the shape error occurred in the sidewall multi-step cutting process were minimized. As the results, the relationship between the cutting conditions and the deformation of micro-structure during micro cutting process was investigated.

Development of MURCC code for the efficient multi-unit level 3 probabilistic safety assessment

  • Jung, Woo Sik;Lee, Hye Rin;Kim, Jae-Ryang;Lee, Gee Man
    • Nuclear Engineering and Technology
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    • v.52 no.10
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    • pp.2221-2229
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    • 2020
  • After the Fukushima Daiichi nuclear power plant (NPP) accident, level 3 probabilistic safety assessment (PSA) has emerged as an important task in order to assess the risk level of the multi-unit NPPs in a single nuclear site. Accurate calculation of the radionuclide concentrations and exposure doses to the public is required if a nuclear site has multi-unit NPPs and large number of people live near NPPs. So, there has been a great need to develop a new method or procedure for the fast and accurate offsite consequence calculation for the multi-unit NPP accident analysis. Since the multi-unit level 3 PSA is being currently performed assuming that all the NPPs are located at the same position such as a center of mass (COM) or base NPP position, radionuclide concentrations or exposure doses near NPPs can be drastically distorted depending on the locations, multi-unit NPP alignment, and the wind direction. In order to overcome this disadvantage of the COM method, the idea of a new multiple location (ML) method was proposed and implemented into a new tool MURCC (multi-unit radiological consequence calculator). Furthermore, the MURCC code was further improved for the multi-unit level 3 PSA that has the arbitrary number of multi-unit NPPs. The objectives of this study are to (1) qualitatively and quantitatively compare COM and ML methods, and (2) demonstrate the strength and efficiency of the ML method. The strength of the ML method was demonstrated by the applications to the multi-unit long-term station blackout (LTSBO) accidents at the four-unit Vogtle NPPs. Thus, it is strongly recommended that this ML method be employed for the offsite consequence analysis of the multi-unit NPP accidents.

A Method of Eliminating Exceptional Elements by Tool Duplication in Cellular Manufacturing System. (셀화 제조를 도입한 FMS에서 공구중복에 의한 예외적 요소의 제거 방법)

  • Chang, Ik;Yoon, Chang-Won;Chung, Byung-Hee
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.20 no.44
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    • pp.297-309
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    • 1997
  • Exceptional Elements(E.E) are generally eliminated by a machine duplication or a subcontract in cellular manufacturing system. One of the advantages in FMS consists of machines capable of multi-processing. This paper presents a method that eliminates E.Es by tool duplication. First, we develop the exceptional operation similarity(EOS) by machine cell-operation incidence matrix and part-operation incidence matrix. The EOS indicates a similarity of unperformable operations in each part when two exceptional parts are assigned to a machine cell. Secondly, a mathematical model to minimize tool duplication is developed by the EOS. Finally, a heuristic algorithm is developed to reflect dynamic situation in process of elimination of exceptional elements by the EOS and the mathematical model. A numerical example is provided to illustrate the algorithm.

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A Study on Optimization for Static Characteristics Analysis of Gantry-Type Machining Centers (문형머시닝센터의 구조해석을 통한 최적화에 관한 연구)

  • Yoo, Deck-Sang
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.14 no.6
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    • pp.122-128
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    • 2015
  • Recently, as the demand for high efficiency, multi-function machine tools has increased, domestic machine tool industries are investing in research and development for Gantry-Type Machining centers. In this thesis, for the purpose of evaluating machining accuracy and designing a machine tool structure, a simplified model of the main frame is suggested. The results show the general characteristics of the optimum design, and the approach is shown as practicable for the preliminary design analysis and improvement of a conceptual design of a Gantry-Type Machining center. This paper's results are expected to improve the static characteristics of Gantry-Type Machine centers. The three-dimensional finite element models proved that the modeling method might be applied to real machine tool structures.