• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.1
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• pp.163-172
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• 1988

An off-line Geometric Adaptive Control Scheme is applied to the milling machine to identify its guideway errors. In the milling process, the workpiece fixed on the bed travels along the guideway while the tool and spindle system is fixed onto the machine. The scheme is based on the exponential smoothing of post-process measurements of relative machining errors due to the tool, workpiece and bed deflections. The guideway error identification system consists of a gap sensor, a, not necessarily accurate, straightedge, and the numerical control unit. Without a priori knowledge of the variations of the cutting parameters, the time-varying parameters are also estimated by an exponentially weighted recursive least squares method. Experimental results show that the guideway error is well identified within the range of RMS values of geometric error changes between machining passes disregarding the machining conditions.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.4
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• pp.92-97
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• 2006

This paper presents an integrated machining error compensation method based on PNN(Polynomial Neural Network) approach and inspection database of OMM(On-Machine-Measurement) system. To efficiently analyze the machining errors, two machining error parameters are defined and modeled using the PNN approach, which is used to determine machining errors for the considered cutting conditions. Experiments are carried out to validate the approaches proposed in this paper. In result, the proposed methods can be effectively implemented in a real machining situation, producing much fewer errors.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.917-921
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• 2000

One of the major limitations of productivity and quality in machining is machining accuracy of the machine tools. The machining accuracy is affected by geometric, volumetric errors of the machine tools. 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 generation of the parabolic face profile. And the method is verified by the parabolic face machining experiment with a vertical three axes NC milling machine. After this study, we will inspect using On-machine measurement and study the repetitive machining by a compensated path

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.851-852
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• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.603-604
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• 2008

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.353-354
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• 2008

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.4
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• pp.44-48
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• 2006

Recently, demand the ultra precision product which is increasing rapidly is used extensively frontier industry field such as semi-conductor, computer, aerospace, precision machine. Ultra precision processing is the portion that is very needed to NT in the field of mechanical engineering. The latest date, together with radical advancement of electronic and photonics industry, necessity of ultra precision processing is on the increase for the manufacture of various kernel parts those are connected with these industrial fields. Specially, require motion accuracy of high resolution of nm order in stroke of hundreds millimeters according as diameter of processing object great and processing accuracy rises. In this case ,the response speed absolute delay because inertial mass of moving part is very large. Therefore, real time motion error compensation becomes very hardly. In this paper, we used ultra precision cutting unit(UPCU) to cope such problem. a UPCU is designed and tested to obtain sub-micrometer from accuracy in diamond turning of flat surfaces. The thermal growth spindle error is compensated for real time using a UPCU driven by piezoelectric actuator along with a laser encoder displacement sensor.

• Journal of the Korean Institute of Intelligent Systems
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• v.7 no.5
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• pp.1-7
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• 1997

In this paper, a neuro-contouring control scheme for the high precision machining of CNC machine tools is descrihed. The proposed control system consists of a conventional controller for each axis and an additional neuro-controller. For contouring control, the contour error must be computed during realtime motion, but generally the contour error for nonlinear contours is difficult to he directly computed. We, therefore, propose a new contour error model to approximate real error more exactly, and here we also introduce a cost function for better contouring performance and derive a learning law to adjust the weights of the neuro-controller. The derived learning law guarantees good contouring performance. Usefulness of the proposed control scheme is demonstrated hy computer simulations.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.11
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• pp.137-144
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• 1998

In this paper we present our research dealing with the problem of tool deflection during the milling. We try to compensate the errors by considering a new tool trajectory. In order to determine the compensated tool trajectory, the problem is divided in three steps : cutting forces model, tool deflection model and trajectory compensation. Starting from experimental data, we determine a cutting forces model., which allows us to anticipate the tool deflection along one nominal path. In order to determine the compensated tool trajectory, we propose in this paper a method of path compensation, called “mirror method”. This method of tool path optimization allows to minimize errors due to tool deflection. Several examples are processed in simulations and validated experimentally.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.838-841
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• 2000

To improve the accuracy of products and 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 well as error analysis of machine tools has been studied for last several decades. OMM(On the Machine Measurement) has been issued to alternate with CMM, pointing out disadvantages of high expenses and lots of setting time in CMM. In this paper, we study 1) the spherical surface manufacturing by volumetric error compensation of machine tool, 2) the system development of OMM without detaching work piece from a bed of machine tool after working. 3) the generation of the finished part profile by On the machine measurement. Furthermore, the output of OMM is compared with that of CMM, and verified the feasibility of the measurement system.