• Korean Journal of Computational Design and Engineering
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• v.1 no.3
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• pp.215-223
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• 1996

Every mechanical part is fabricated with the variations in its size and shape, and the allowable range of the variation is specified by the tolerance in the design stage. Geometric tolerances specify the size or the thickness of each shape entity itself or its relative position and orientation with respect to datums while considering their order of precedence. It would be desirable if the assemblability of parts could be verified in the computer when the tolerances on the parts are store together with the geometric model of the parts of an assembly and their assembled state. Therefore, a new method is proposed to represent geometric tolerances and to determine the assemblability. This method determines the assemblability by subdividing the ranges of relative motion between parts until there exists the subdivided regions that do not cause the interference.

• Journal of the Korean Society for Precision Engineering
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• v.10 no.3
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• pp.205-219
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• 1993

제품의 기하학적 칫수 공차는 생산제품의 품질관리에 매우 종요하며, 측정기기의 발달과 함께, 컴퓨터를 이용한 기하하적 공차 해석의 수요와 경향은 늘고 있는 추세이다. 본 논문에서는, ISO의 공차 정의에 기초한 공차들(진직도공차, 편평도공차, 진원도공차, 평행도공차, 직각도공차, 윤곽공차)을 해석할 수 있는 컴퓨터 모듈이 개발되었다. 특히 윤곽공차의 경우 측정프로브의 반경의 효과가 배제되는 알고리즘을 개발하였다. 개발된 컴퓨터 모듈을 실제적인 측정작업에 적용하였으며, 고종도와 고효율성을 보임을 입증하였다.

• Proceedings of the Safety Management and Science Conference
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• 2002.05a
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• pp.99-103
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• 2002

It is the basic requirement of product characteristics to specify geometric dimensions and tolerances during design process of parts assembly. Therefore, there are many tolerance stack analysis method to explain tolerance zone. Tolerance stack analysis is to calculate gap using tolerances which includes geometric and coordinate dimension. In this study, we compared several different stack analysis method and try to suggest more general method called the Virtual Method to analyze tolerance stack.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.6
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• pp.78-89
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• 1996

Every mechanical component is fabricated with the variations in its size and shape, and the allowable range of the variation is specified by the tolerance in the design stage. Geometric tolerances specify the size or the thickness of each shape entity itself or its relative position and orientation with respect to datums. Since the range of shape variation can be represented by the variation of the coordinate system attached to the shape, the transformation matrix of the coordinate system would mathematically express the range of shape variation if the interval numbers are inserted for the elements of the transformation matrix. For the shape entity specified by the geometric tolerance with reference to datums, its range of variation can be also derived by propagating the transformation matrices composed of interval numbers. The propagation depends upon the order of precedence of datums.

• Journal of Korean Institute of Industrial Engineers
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• v.31 no.1
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• pp.36-43
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• 2005

It is the basic requirement of design process of parts assembly to specify geometric dimensions and tolerances of product characteristics. Among them, tolerance stack analysis is one of the important methods to specify tolerance zone. Tolerance stack analysis is to calculate gap using tolerances which includes geometric and coordinate dimensions. In this study, we suggested more general method called the virtual method to analyze tolerance stack. In virtual method, tolerance zone is formed by combination of dimensional tolerance, geometric tolerance and bonus tolerance. Also tolerance zone is classified by virtual boundary condition and resultant boundary condition. So gap can be defined by combination of virtual boundary and/or resultant boundary. Several examples are used to show the effectiveness of new method comparing to other methods.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.7
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• pp.122-132
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• 1996

It can be expected that the tolerances of the parts are assigned systematically and thus the parts are designed considering the assemblability in advance in the design stage, if the tolerances can be stored together with the geometric model of the parts and the assemblability of the parts is verified in the computer. In other words, an example of the concurrent engineering is realized. To verify the concepts described above, a new method is proposed to verify the assemblability when the tolerance information and the geometric model of the parts of an assembly are given. This method determines the assemblability by subdividing the range of relative motion between parts until the subdivided region corresponding to free of interference can be found.

• Journal of Korean Institute of Industrial Engineers
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• v.17 no.2
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• pp.75-86
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• 1991

This paper presents a methodology to enable the tolerances on mating parts of an assembly to be specified and be compatible to the precision of an assembly robot so as to achieve maximum system performance. The measure of performance is defined as the Probability of Successful Assembly (PSA). A typical loose fastener assembly, usually called peg-in-a-hole is investigated. The Geometric Tolerancing System is adopted to represent position tolerances of mating parts. Two models are presented by considering modifiers on a position tolerance, Regardless of Feature Size (RFS) and Maximum Material Condition (MMC). Using these models, it is analyzed how the Standard Limits and Fits recommended by ANSI influence the performance of an assembly robot. For this analysis, the Standard Limits and Fits are transformed to the representation scheme of the Geometric Tolerancing System. Due to low PSAs when the Standard Limits and Fits are taken into account, the effect of chamfers around a hole is also analyzed.

• Journal of Korean Institute of Industrial Engineers
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• v.31 no.4
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• pp.316-333
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• 2005

Although some successful recognition algorithms have been developed, most of them did emphasize on extracting accurate interpretations without considerations of manufacturability. Evaluating the manufacturability for multiple features leads to produce the machining sequences. In this paper, the A* algorithm guarantees the optimal setup sequences with minimizing the machining cost. Also, tolerances including surface roughness are converted to STEP formats to be utilized for more reliable process plans. Finally, decision tables are used to create the detailed operational sequences based on geometric tolerances and surface roughness. Machining parameters such as feed, depth of cut, and cutting speed for each operation are added to the routing sheet. Windows are presented to show how the entire system works for a sample part.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.1
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• pp.67-72
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• 2011

The main objective of this paper is obtaining the optimal carburizing hours which impacts geometric tolerances, OPD(Over Pin Diameter), runout, hardness and fatigure strength of SCM415 spur gear. In order to observe the deformation of the gear, the circularity, squareness, OPD(Over Pin Diameter) and runout were measured at 3hour, 4hour and 5hour respectively. As the result, the 3hour situation is the best, which very similar with the 4hour one. Afterwards, with the purpose of getting the result of gear hardness, the surface hardness, maximum hardness and interior hardness were measured. The result is 5h situation is the best, and it's similar with 4hour one. At last, the fatigue tests have been done which receive the result that the 4h situation showed 9~12% fatigue strength improvement compared with the 3h and 5h ones. To sum up the results, the 4hour situation shows the best performance in accuracy, hardness and fatigue strength.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.10
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• pp.63-68
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• 2000

We present an automatic inspection system which been developed to evaluate the geometric tolerances of the optical fiber connectors with an dimensional accuracy of$\pm0.1\mnm$. The main part of the inspection system comprises a series of machine vision and laser scanning probes to measure the internal and external circle diameters along with concentricity by making the most of advanced edge detection algorithms. Actual experimental results obtained through various repeatability tests demonstrate that the system well satisfies the required industrial demands for in-situ inspection of optical fiber connections in real manufacturing environment.