• 한국생산제조학회지
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• 제7권4호
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• pp.79-88
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• 1998

This study deals with the development of CAM system which can machine and measure any shape of mold and die by machining center and coordinate measureing machine . The overall goal of the CAM system is to achieve the mold and die machining , from digitizing through to final cutting. The hardware of the system comprises PC and machining center. CMM. There are three steps in the mold and die machining. (1) measuring of physical model by the CMM, (2) geometric modeling by the CAD system, (3) generation of NC code by the tool path compensated for tool radius. It is developed a software package, with which can conduct a micro CAM system in the PC without economical burden.

• 한국공작기계학회논문집
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• 제17권4호
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• pp.140-145
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• 2008

Recently more complex geometric shapes, including freeform surfaces, are adopted for the design of products to emphasize style or beauty. Modeling of these products is extremely difficult or often impossible. Reverse engineering is the latest technology that can solve the problem by generating CAD models from the physical mockups or prototype models. Reverse engineering uses the coordinate measuring machine(CMM) to get the shape data of products. CMM is limited by the size of the product; therefore it must need the feature to solve it. The tooling-ball which is generally used for feature has difficulty in being used for soft products. Besides, the higher the accuracy of the tooling-ball is, the more expensive its cost is. This study will develop the feature of high accuracy without additional tools and compare the difference of accuracy by it.

• 한국정밀공학회지
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• 제10권4호
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• pp.16-29
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• 1993

The objective of this research is in the development of a flexible 3-dimensional inspection system for the sculptured surface by integrating the Coordinate Measuring Machine (CMM), CAD database, and vision system. To achieve the proposed flexible inspection system, two research categories are discussed in the study: new inspection planning method includes a new measuring point selection method and various new probe path generation methods. The object recognition and localization process for the unknown surface can be easily carried out by introducing a new concept called "Z-Layer". The experimental results indicate that the developed flexible inspection system, with the proposed algorithm, can be inplemented in real situation.situation.

• 한국정밀공학회지
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• 제33권4호
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• pp.295-301
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• 2016

The out-of-squareness is one of the error sources that affect the positioning accuracy of machine tools and coordinate measuring machines. Laser interferometer is widely used to measure the position and angular errors, and can measure the squareness using an optical square. However, the squareness measurement using the laser interferometer is difficult, as compared to other errors due to complicated optics setup and Abbe's error occurrence. The effect of out-of-squareness mainly appears at the face-diagonal of the movable plane. The diagonal displacements are also affected by the position dependent geometric errors. In this study, the squareness estimation techniques via diagonal displacement measurement using the laser interferometer without an optical square were proposed. For accurate estimation and measurement time reduction, the errors selected from proposed discriminant were measured. Discrepancy between the proposed technique with the laser interferometer (with an optical square) result was $0.6{\mu}rad$.

• Journal of Mechanical Science and Technology
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• 제19권8호
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• pp.1576-1581
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• 2005

Generally, the optical components are fabricated by grinding, lapping, and polishing. And, those processes take long time to obtain such a high surface quality. Therefore, in the case of large optical component, the on-machine inspection (OMI) is essential. Because, the work piece is fragile and difficult to set up for fabricating and measuring. This paper is concerned about a swing-arm method for measuring surface profile of large optical concave mirror. The measuring accuracy and uncertainty for suggested method are studied. The experimental results show that this method is useful specially in lapping process with the accuracy of $3\~5\;{\mu}m$. Those inspection data are provided for correcting the residual figuring error in lapping or polishing processes.

• 대한치과교정학회지
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• 제30권5호
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• pp.565-578
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• 2000

한국인의 치열의 특성을 고려한 Straight-Wire Appliance(SWA)의 제작을 위한 자료를 얻기 위하여 18세 이상 25세 사이의 한국인 성인 정상교합자를 1) 구강악안면부에 기능장애가 없고, 2) 양호한 치열궁 형태와 긴밀한 구치부 교합관계를 가지며, 3) 교합이 전후방적으로 앵글 분류 I 급의 관계를 가지며, 4) 간단한 수복 치료 외에 교정치료나 보철치료를 받지 않았으며, 특히 치아의 순면과 협면의 형태에 변형을 초래한 치과 치료를 받지 않았으며, 5) 단정한 안모를 가진 자를 선발 기준으로 정하여 선발하였다. 선정된 정상 교합자의 상, 하악 인상을 채득하고, 교정용 석고 모형을 제작하였다. 얻어진 치과 석고모형을 분석하여, Andrews의 Six keys to optimal occlusion에 부합되는 표본을 5 명의 숙련된 교정의사들이 선별하여 한국인 성인 정상교합자 치열의 석고 모형 155쌍(남자 92쌍,여자 63쌍)을 얻었다. 이들을 대상으로 정밀측정장비인 Coordinate Measuring Machine(CMM, MPC802, WEGU-Messtechnik, Germany)을 이용하여 3차원 digitization을 시행하고, 계측프로그램을 작성하여 SWA 제작을 위하여 필요한 Angulation, Inclination, In-and-Out, Molar offset angle, Arch-form 등을 측정하였다. 측정을 시행하기 전에, CMM을 이용한 3차 원 digitization의 오차에 대한 검증을 실시하였고, 3차원 digitization과 컴퓨터를 이용한 형태학적 분석법과 기존의 수작업에 의한 분석법의 신뢰도에 대한 분석을 실시하였다. 이상의 연구를 통하여 얻은 결론은 다음과 같다. 1. 치과 석고모형의 3차원 digitization에 CMM을 적용하여 mesh size 0.25 mm, 0.5 mm, 1.0 mm로 등간격 디지타이징하는 것은 모두 받아들일 수 있으며, 측정의 효율성을 고려할 때 1.0 mm간격으로 등간격 디지타이징 하는 것이 바람직하다. 2. 3차원 digitization과 컴퓨터를 이용한 방법이 Andrews의 방법에 기반한 수작업 방법보다 신뢰성이 높다. 3. 3차원 digitization과 컴퓨터를 이용한 방법으로 한국인의 치열의 형태학적 특성에 맞는 SWA의 제작을 위한 자료를 채득하였다.

• International Journal of Precision Engineering and Manufacturing
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• 제5권1호
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• pp.60-68
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• 2004

The purpose of this paper is to establish an effective inspection system by using OMM (On-Machine Measurement) system based PC-NC. This system can reduce manufacturing lead time because a workpiece is inspected at every machining process and the manufacturing system which includes inspection faculty is able to realize on-line process on CNC machining center. The proposed OMM system is composed of a few algorithms for determination of inspection parameters. It is accomplished by determining the number of measuring points, their location, measuring path using fuzzy logic, Hammersley's method, TSP (Traveling Salesperson Problem) algorithm. The inspection feature applied to this system is based on machining feature. This method is tested by simulation and experiment that are analyzed measuring data and geometry tolerance.

• 한국공작기계학회논문집
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• 제12권5호
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• pp.15-23
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• 2003

A feature-based inspection planning system is proposed in this research to develop more efficient measuring methodology for the OMM(On-Machine Measurement) or CMM(coordinate Measuring Machine) for complicated workpiece having many primitive form features. This paper is proposed solution that optimum inspection sequence of the objective features. The sequences are determined by analyzing the feature information such as the nearest relationship and the possible probe-approach direction(PAD) of the features, and forming feature groups. A series of heuristic rules are developed to accomplish it. Also, each feature is decomposed into its constituent geometric elements for inspection process, and then the number of sampling points, location of the measuring points, optimum probing path are determined.

• International Journal of Precision Engineering and Manufacturing
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• 제9권4호
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• pp.16-21
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• 2008

The demand for three-dimensional (3D) shape measurements is increasing in a variety of fields, including the manufacture of molds and dies. The most popular technology for 3D shape measurement is the coordinate measuring machine (CMM) with a contact trigger probe. Although a CMM provides a high degree of accuracy, it is inefficient due to its long measuring time. It also has difficulty measuring soft objects that can be deformed by the touch of the contact probe. In addition, a CMM cannot digitize areas that are difficult to reach, and cannot capture very minute details on the surface of complex parts. For these reasons, optical non-contact measurement techniques are receiving more attention since they eliminate most of the problems associated with contact methods. Laser scanning is emerging as one of the more promising non-contact measurement techniques. This paper describes various acquisition considerations for laser scanning, including the accuracy of the 3D scan data, which depends on the charge-coupled device (CCD) gain and noise. The CCD gain and noise of a 3D laser scanner are varied while keeping the other conditions constant, and the measurement results are compared to the dimensions of a standard model. The experimental results show that a considerable time savings and an optimum degree of accuracy are possible by selecting the proper CCD gain and noise.

• 한국산업융합학회 논문집
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• 제17권3호
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• pp.184-193
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• 2014

Machine vision systems is applied for various industries such as optimize your spending, automate your production and maximize your efficiency. This research is effective for most optimal light condition of machine vision that technology was applied bald outside human visual acuity. Image processing converts a target image captured by a CCD camera into a digital signal and then performs various arithmetic operations on the signal to extract the characteristics of the target, such as points, lines, circles, area and length. The mathematical concepts of convolution and the kernel matrix are used to apply filters to signals, to perform functions such as extracting edges and reducing unwanted noise. This research analyze and compares matching ratio with reference image and search for optimal lighting condition in accuracy that user wants coming input image according to brightness change of lighting.