• Title/Summary/Keyword: Dimensional Tolerance

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A Study on Dimensional Accuracy in Circular Pocket Machining of SCM415 Steel (SCM415강의 원형포켓 가공시 치수정밀도에 관한 연구)

  • Shin, Mi-Jung;Choi, Chul-Woong
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.18 no.9
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    • pp.58-63
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    • 2019
  • In this research, we examine the change of dimensional accuracy in the cutting process while changing cutting conditions such as feed rate and spindle rotational speed with chromium molybdenum steel (SCM415) material and TiCN- and TiAlN-coated end mill tools. According to dimensional accuracy measurement, TiCN-coated tool displays the most accurate dimensional tolerance at ${\varnothing}20mm$ at feed rates of 200 mm/min and 250 mm/min at a spindle rotation speed of 4,000 rpm. The largest dimension of the coating tool was able to make the TiAlN-coated tool suitable when comparing the smallest dimension.

A Study on Quality Improvement Method for Manufacturing Process Plan (제조공정계획의 품질개선기법에 관한 연구)

  • Kim, In-Ho
    • Korean Journal of Computational Design and Engineering
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    • v.13 no.3
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    • pp.235-242
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    • 2008
  • This paper proposes a method for improving the process plan quality by use of dimensional tolerances. Dimensioning and tolerancing plays a key role in manufacturing process plan because the final part must ensure conformance with the dimensions and tolerances in its drawing. As a first step for the improvement of process plan quality, two resultant tolerances in design and process plan should be compared each other, and so a tolerance chart is used for acquisition and comparison of the two tolerances. In addition to two kinds of design and manufacturing tolerances, operational sequences or paths for the resultant dimension and tolerance are additionally recognized for measuring the quality of process plan quantitatively. Rooted tree is applied to find the related paths for the manufacturing resultant tolerances. A quality coefficient is defined by the components of two tolerances and their relations, the paths related to manufacturing resultant tolerances and the difficulty of an operation. In order to improve the quality of manufacturing process plan, the paths that two kinds of tolerances are the same or different in the rooted tree are recognized respectively and a method for tolerance rearrangement is developed. A procedure for improving the quality is suggested by combining the coefficient and the tolerance rearrangement method. A case study is applied to illustrate the efficiency of improvement method.

Fault Diameter and Fault Tolerance of Gray Cube (그레이 큐브의 고장 지름(Fault Diameter)과 고장 허용도(Fault Tolerance))

  • Lee, Hyeong-Ok;Joo, Nak-Keun;Lim, Hyeong-Seok
    • The Transactions of the Korea Information Processing Society
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    • v.4 no.8
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    • pp.1930-1939
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    • 1997
  • In this paper, we analyze the fault diameter and fault tolerance of Gray cube proposed recently in [12]. fault diameter of an interconnection network is one of the important network measures concerning the distance between nodes when some nodes fail. It is showed that fault diameter of n-dimensional Gray cube having $2^n$ nodes is [(n+1)/2]+2, ($n{\ge}3$). It means the increment of the longest distance between nodes under node-failure is only constant factor. Comparing the result with the fault diameter of well-known hypercube, the longest routing distance of a message in a Gray cube under node-failure is about the half of that hypercube.

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A Study on the Development of On Machine Measuring System using 3-Dimensional solid model (3차원 형상기반 기계상 측정 시스템 개발에 관한 연구)

  • Koo B. K.;Ryu J. K.;Kim S. Y.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2002.02a
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    • pp.3-10
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    • 2002
  • In this study on machine measuring system based on solid feature was developed. This system was applied with injection mold using 3 dimensional solid modeler for verification. Developed program include pre-processor, main processor, and post processor. In pre-processor there are functions which check intersection, simulate motion of probe and calculate measuring time. Main processor generates measuring path and output NC code in Unigraphics. In post-processor functions that include evaluation of undercut or overcut and display of measuring procedure are offered. In addition analysis module for quality control of measured data on manufactured product was developed with geometric and dimensional tolerance concept. As the result developed program could get stability of system, precision of product, rapidity and cost down of manufacturing process compared with before measuring process.

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Bit-level 1-dimensional systolic modular multiplication (비트 레벨 일차원 시스톨릭 모듈러 승산)

  • 최성욱;우종호
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.33B no.9
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    • pp.62-69
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    • 1996
  • In this paper, the bit-level 1-dimensional systolic array for modular multiplication is designed. First of all, the parallel algorithm and data dependence graph from walter's method based on montgomery algorithm suitable for array design for modular multiplication is derived. By the systematic procedure for systolic array design, four 1-dimensional systolic arrays are obtained and then are evaluated by various criteria. As it is modified the array which is derived form [0,1] projection direction by adding a control logic and it is serialized the communication paths of data A, optimal 1-dimensional systolic array is designed. It has constant I/O channels for expansile module and it is easy for fault tolerance due to unidirectional paths. It is suitable for RSA cryptosystem which deals iwth the large size and many consecutive message blocks.

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The Analysis of Trajectory Tracking Error Caused by the Tolerance of the Design Parameters of a Parallel Kinematic Manipulator (병렬로봇의 설계 공차가 궤적 정밀도에 미치는 영향 분석)

  • Park, Chanhun;Park, DongIl;Kim, Doohyung
    • The Journal of Korea Robotics Society
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    • v.11 no.4
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    • pp.248-255
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    • 2016
  • Machining error makes the uncertainty of dimensional accuracy of the kinematic structure of a parallel robot system, which makes the uncertainty of kinematic accuracy of the end-effector of the parallel robot system. In this paper, the tendency of trajectory tracking error caused by the tolerance of design parameters of the parallel robot is analyzed. For this purpose, all the position errors are analyzed as the manipulator is moved on the target trajectory. X, Y, Z components of the trajectory errors are analyzed respectively, as well as resultant errors, which give the designer of the manipulator the intuitive and deep understanding on the effects of each design parameter to the trajectory tracking errors caused by the uncertainty of dimensional accuracy. The research results shows which design parameters are critically sensitive to the trajectory tracking error and the tendency of the trajectory tracking error caused by them.

Effects of processing parameters of alumina tape on the constrained sintering characteristics of LTCC (LTCC의 constrained sintering 특성에 미치는 알루미나 테잎의 공정변수영향)

  • Park, Seong-Dae;Cho, Hyun-Min;Yoo, Myong-Jae;Lee, Woo-Sung;Kang, Nam-Kee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.05c
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    • pp.245-248
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    • 2003
  • 저온동시소성 세라믹으로 제작된 모듈을 고주파 대역에 적용할 경우 dimension의 오차는 모듈 특성의 오차를 유발시킨다. Constrained sintering 기술은 XY 방향의 수축을 억제시킴으로써 세라믹 소결체의 dimensional tolerance를 향상시키기 위하여 개발된 기술이다. LTCC의 소성온도에서는 수축하지 않는 비소성층을 LTCC 적층체의 위 아래에 함께 적층시킴으로써 XY 방향의 수축은 기계적으로 억제되며, 두께 방향으로만 수축이 일어난다. 본 연구에서는 LTCC 기판을 constrained sintering 방법으로 소성하고, 그 특성값을 일반적인 소성방법으로 제작하였을 때와 비교하였다. 알루미나 테잎의 제조조건 빛 적층조건을 변화시켜 이에 따른 면수축 제어 특성의 변화를 고찰하였다. 실험결과 알루미나 테잎의 고형분 용량과 부착층의 두께가 면수축 제어를 위하여 고려되어야할 주요 인자임을 확인할 수 있었다.

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Three-Dimensional Stacked Memory System for Defect Tolerance (적층 구조의 3차원 결함극복 메모리)

  • Han, Se-hwan;You, Young-Gap;Cho, Tae-Won
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.47 no.11
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    • pp.23-29
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    • 2010
  • This paper presents a method for constructing a memory system using defective memory chips comprising faulty storage blocks. The three-dimensional memory system introduced here employs a die-stacked structure of faulty memory chips. Signals lines passing through the through-silicon-vias (TSVs) connect chips in the defect tolerant structure. Defective chips are classified into several groups each group comprising defective chips having faulty blocks at the same location. A defect tolerant memory system is constructed using chips from different groups. Defect-free storage blocks from spare chips replace faulty blocks using additional routing circuitry. The number of spare chips for defect tolerance is $s={\ulcorner}(k{\times}n)/(m-k){\urcorner}$ to make a system defect tolerant for (n+s) chips with k faulty blocks among m independently addressable blocks.

Fabrication Assessment Method for Dimensional Quality Management of Curved Plates in Shipbuilding and Offshore Structures (선박 및 해양 구조물 곡부재 치수 품질 관리를 위한 가공완성도 평가)

  • Kwon, Ki-Youn;Lee, Jaeyong
    • Journal of Ocean Engineering and Technology
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    • v.32 no.2
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    • pp.106-115
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    • 2018
  • The forward and afterward parts of ships and offshore structures are designed to improve the fuel consumption performance. These are made of curved plates with a large thickness. If a fabricated curved plate has some dimensional errors, a lot of additional cost is incurred in the assembly process. Thus, an accurate dimensional assessment is very important for fabrication. In this paper, we propose an assessment method for the dimensional quality management of curved plates. This can be applied to data measured using a variety of three-dimensional instruments, with boundary measurement points automatically classified and sorted to create a measurement surface. The assessment is evaluated after matching the CAD surface and the measured surface considering constrained conditions. The fabrication assessment is evaluated as a probability of how much the tolerance is satisfied.

An Algorithm for 3-Dimensional Reconstruction of Clinical Ultrasonic Image (임상적 초음파 신호의 3차원 영상처리를 위한 알고리즘)

  • 진영민;우광방;유형식
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.38 no.8
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    • pp.658-666
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    • 1989
  • In this paper, an efficient algorithm for estimation volume and surface area and a reconstruction algorithm for 3-dimensional graphics are presented.In order to improve computing efficiency, the graph theory is utilized and the algorithm to obtain proper contour points is developed by considering several tolerances. Search for the contour points is limited by the change of curvature of cross sectional contour to provide efficiency in searching the minimum cost path. In computer simulation of these algorithms, the results show that, for the tolerance values of 1.001 and 1.002, the execution time reduced to 66%-80% and the error for the measured value is less than 3%. The reconstructed 3-dimensional images from the cross sections can be analyzed in many directions using the graphic scheme.

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