• Title/Summary/Keyword: On the Machine Measurement(OMM)

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A study of On-Machine Measurement for PC-NC system

  • Yoon, Gil-Sang;Kim, Gun-Hee;Cho, Myeong-Woo;Seo, Tae-Il
    • International Journal of Precision Engineering and Manufacturing
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    • v.5 no.1
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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.

The Analysis of Measuring Error in OMM System (OMM 시스템에서의 측정오차 해석)

  • 이상준;김선호;김옥현
    • Journal of the Korean Society for Precision Engineering
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    • v.15 no.5
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    • pp.34-42
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    • 1998
  • This paper describes an analysis of measuring error of on the machine measuring(OMM) system which directly measures machined surface dimensions using scanning probe on a CNC milling machine. 21 inch TV shadow mask mould clamped to a pallet was measured using PTP(point to point) measuring algorithm in OMM system and the results were compared with those using coordinate measuring machine(CMM). The OMM error was evaluated by probe error, stylus contact error, center shift error, repeatability, work-piece clamping error and etc. The results show that elastic deformation of the pallet is most affecting factor on the measuring error, thus pallet design and clamping method need very careful cosiderations.

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The Development of 3D based On-Machine Measurement Operating System (3D 기반의 기상측정 운영시스템 개발)

  • 윤길상;최진화;조명우;김찬우
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.7
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    • pp.145-152
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    • 2004
  • This paper proposed efficient manufacturing system using the OMM (on-machine measurement) system. The OMM system is software based 3D modeler for inspection on machine and it is interfaced tool machine with RS232C. The software is composed of two inspection modules that one is touch probe operating module and the other is laser displacement sensor operating module. The module for touch probe has need of inspection feature that extracted it from CAD data. Touch probe moves to workpiece by three operating modes as follows: manual, general and automatic mode. The operating module of laser displacement sensor is used inspection for profile and very small hole. An Advantage of this inspection method is to be able to execute on-line inspection during machining or after it. The efficiency of proposed system which can predict and definite the machining errors of each process is verified, so the developed system is applied to inspect the mold-base(cavity, core).

A Study of an OMM System for Machined Spherical form Using the Volumetric Error Calibration of Machining Center (머시닝센터의 체적오차 보상을 통한 구면 가공형상 측정 OMM시스템 연구)

  • Kim, Sung-Chung;Kim, Ok-Hyun;Lee, Eung-Suk;Oh, Chang-Jin;Lee, Chan-Ho
    • Journal of the Korean Society for Precision Engineering
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    • v.18 no.7
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    • pp.98-105
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    • 2001
  • The machining accuracy is affected by geometric, volumetric errors of the machine tools. To improve the product quality, we need to enhance the machining accuracy of the machine tools. To this point of view, measurement and inspection of finished part as error analysis of machine tools ahas been studied for last several decades. This paper suggests the enhancement method of machining accuracy for precision machining of high quality metal reflection mirror or optics lens, etc. In this paper, we study 1) the compensation of linear pitch error with NC controller compensation function using laser interferometer measurement, 2) the method for enhancing the accuracy of NC milling machining by modeling and compensation of volumetric error, 3) the spherical surface manufacturing by modeling and compensation of volumetric error of the machine tool, 4) the system development of OMM without detaching work piece from a bed of machine tool after working, 5) the generation of the finished part profile by OMM. Furthermore, the output of OMM is compared with that of CMM, and verified the feasibility of the measurement system.

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On-Machine Measurement of Sculptured Surfaces Based on CAD/CAM/CAI Integration : I. Measurement Error Modeling (CAD/CAM/CAI 통합에 기초한 자유곡면의 On-Machine Measurement : I. 측정오차 모델링)

  • Cho, Myeong-Woo;Lee, Se-Hee;Seo, Tae-Il
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.10
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    • pp.172-181
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    • 1999
  • The objective of this research is to develop a measurement error model for sculptured surfaces in On-Machine Measurement (OMM) process based on a closed-loop configuration. The geometric error model of each axis of a vertical CNC Machining center is derived using a 4${\times}$4 homogeneous transformation matrix. The ideal locations of a touch-type probe for the scupltured surface measurement are calculated from the parametric surface representation and X-, Y- directional geometric errors of the machine. Also, the actual coordinates of the probe are calculated by considering the pre-travel variation of a probe and Z-directional geometric errors. Then, the step-by-step measurement error analysis method is suggested based on a closed-loop configuration of the machining center including workpiece and probe errors. The simulation study shows the simplicity and effectiveness of the proposed error modeling strategy.

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Development of Typical On-Machine Measurement S/W based 3D modeler (3D 모델러 기반의 기상측정 소프트웨어 개발)

  • 김찬우;신장순;윤길상;조명우;박균명;유택인
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.1581-1584
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    • 2003
  • This paper proposed efficient manufacturing system using OMM(on-machine measurement) system and OMM operating S/W based 3D modeler. A Developed program connected tool machine with RS232C. It is composed two operating system that touch probe operating and laser displacement sensor operating system. A program for touch probe possible measure considered inspection feature and CAD data. The laser operating program is used inspection for profile. very small hole using installed feature data. This system is applied manufacturing line of mold(cavity, core) also verification of efficiency manufacturing process that production, reduction machining error of each process

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A study on the OMM error compensation considering the thermally induced errors (열변형 오차를 고려한 기상측정 오차 보정에 관한 연구)

  • 박규백;송길홍;조명우;권혁동;서태일
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.399-404
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    • 2002
  • Improvement of measuring accuracy is an essential part of quality control manufacturing process. The OMM is less than the CMM in measure accuracy but the OMM system is more efficient, easier to use than other measurement system. About 40~70% of the machine tool errors are induced by the thermal errors. Therefore, a key requirement for improving the measuring accuracy is to reduce the geometric and thermal errors. Thermal errors are measured by a ball bar system and predicted by the thermal error modeling. Furthermore, using the pre-defined thermal error map approach compensates the geometric accuracy of the OMM. Appropriate experiments are performed using ball-bar system, temperature measuring devices and touch-type probe. Compensated results are compared with those obtained using CMM to verify the proposed methods.

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A Study on the Development of a Feature Based Inspection Planning System for On-Machine Measurement Process (특징형상기반의 측정계획시스템 개발에 관한 연구)

  • 정석우;윤길상;조명우
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.10a
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    • pp.654-658
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    • 2002
  • The purpose of this paper is to establish an effective featured based inspection planning system for OMM(On-Machine Measurement) process. In this system, an effective inspection process planning is accomplished by determining the number of measuring points, their locations and probing paths using fuzzy logic, Hammersley method and TSP problem. Also, an effective collision-free algorithm Is proposed based on the EZ-map analysis. All the inspection planning processes are performed based on the defined inspection features those are derived from the CAD database. Proposed inspection planning method is simulated for the given sample wrokpieces, and the results are analyzed. The results show that the proposed method can be successfully implemented in real OMM process.

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Error Analysis of Free-Form Artifact using 3D Measurement Data (3차원 측정 데이터를 이용한 자유곡면 가공물의 오차해석)

  • 김성돈;이성근;양승한;이재종
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2001.04a
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    • pp.439-442
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    • 2001
  • The Accuracy of a free-form artifact is affected by machine tool errors, machining process errors, environmental causes and other uncertainty. This paper deals with methodological approach about machine tool errors that are defined the relationship between CMM and OMM inspections of the free-form artifact. In order to analyze the measurement data, Reverse engineering was used. In other words, Surface of Free-Form Artifact is generated by NURBS surface approximation method. Finally, Volumetric error map is made to compare surface of CMM data with that of OMM data.

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