• Journal of the Korean Society of Manufacturing Process Engineers
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• v.1 no.1
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• pp.5-14
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• 2002

Hemisphere shapes were machined for different tool paths and machining conditions with ball endmill cutters. It was also found out how feedrate affect the precision of the machining and also tried to study the most suitable feedrate in specific cutting condition. Tool deflection, cutting forces and shape accuracy were measured according to the inclination position of the sculptured surface. As the decreasing of inclination position angle, the tool deflection was increased due to the decreased cutting speed when the cutting edge is approaching toward the center. Tool deflection when upward cutting IS obtained less than that of downward cutting and down-milling in upward cutting showed the least tool deflection for the sculptured surface. For down-milling, the cutting resistance of the side wall direction is larger than that of feed direction. It was found that the tool deflection is getting better as tool path is going to far from the center for convex surface.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.4
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• pp.173-180
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• 2000

In the process of grinding a long slender type workpiece, such as ballscrew, by the external cylindrical grinding machine, the cylindricity of the workpiece depends on the distance of rests, the stiffness of supports, the diameter and material of workpiece. Conventionally the process needs to be supported by one or more rests to prevent static deflection and vibration. In this paper, the optimal position of the rests was investigated in order to minimize the cylindricity due to the static deflection, by taking compliance of the workpiece and structure into account. In order to obtain the optimal position of rests, a new modeling that is considering the spring effect of all support elements was established. Since it is so complicated to obtain the optimal position analytically for various conditions due to discontinuity, a genetic algorithm u as utilized.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.237-240
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• 2004

Indexable end mills, which consist of inserts and cutter body, have been widely used in roughing of parts in the mold industry. The geometry and distribution of inserts on cutter body are determined by application. This paper proposes analytical cutting force model for indexable flat end-milling process. Developed cutting force model uses the cutting-condition-independent cutting force coefficients and considers runout, cutter deflection and size effect for the accurate cutting force prediction. Unlike solid type endmill, the tool geometry of indexable endmill is variable according to the axial position due to the geometry and distribution of inserts on the cutter body. Thus, adaptive algorithm that calculates tool geometry data at arbitrary axial position was developed. Then number of flute, angular position of flute, and uncutchip thickness are calculated. Finally, presented model was validated through some experiments with aluminum workpiece.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.9 no.4
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• pp.53-58
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• 2010

In this paper, the output characteristics of PSD(Position Sensetive Detector) used in measurement system are described. Most of the precision measurment systems are accomplished by a laser diode(LD), a photo diode(PD) and PSD(Position Sensetive Detector), which are used in reflection of mirror or projection of infrared spectrometer. But it is especially restricted by resolution of PD and PSD in nano-measurement. A new inclined light methods into the PSD are employed in the surface measurement system for increasing the resolution. As the results, we can know that the output characteristics of detective senser (PSD) become more than 2 or 3 times by changing inclined angle(range: 5 degree) compared with common angle. In addition, the experiment results are confirmed that the change of inclined angle is not affecting to the linearity and repeating.

• Journal of the Korean Society for Precision Engineering
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• v.5 no.4
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• pp.24-31
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• 1988

The Upper Bound Solution has been used to investigate the effect of the various parameters on the floating-plug tube-drawing precess. A kinematically admissible velocity field considering the change of the tube thickness is proposed for the deformation process. Taking into account the position of the plug in the deforming region, shear energy at entrance and exit, friction energy on contact area, homogeneous energy are calculated. The theoretical values in proposed velocity field are good agreement with experimental values, It is investigated that the tube thickness in the deforming region is changed slightly toward minimization of deforming energy and then the drawing stress in lower than the crawing stress in the velocity field that the tube thickness is uniform.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.9
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• pp.129-135
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• 2010

The state feedback-based position controller for the voice coil motor(VCM) used in precise automated manufacturing processes is proposed and analyzed in this paper. The proposed controller has advantage over the conventional cascade-type P-PI controller in terms of the gain selection and the controller interference. The feasibility of the presented idea is verified by experimental results on a designed VCM.

• Journal of Radiation Industry
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• v.6 no.3
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• pp.245-249
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• 2012

Demand of fluid flow visualization has increased in industrial processes, because medical imaging technology is highly developed. As a part of the industrial process imaging technology, industrial single photon emission computed tomography (SPECT) system was developed to measure the cross-sectional distribution of the process fluid. The SPECT consists of 36 NaI (Tl) detectors with the hexagonal configuration. Reconstructed images were acquired for various positions of radioactive source to estimate SPECT device performance. To evaluate the reliability of the experimental results, the Monte Carlo simulation results are compared with experimental results. In general, the experimental and simulation results were consistent. However, as the source position was getting far from the center of the reactor, the accuracy of reconstructed images was compromised. It seems to be due to the inconsistent spatial resolution of the collimators according to the source position.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.403-403
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• 2000

Generally estimation of driving direction uses the way which uses lane detection and vanishing point in autonomous-driving system. Especially we use Sub-window for decreasing Process time when we detect lane, but fixed sub-window can not detect lane because of some factors in road image. So we suggest algorithm using one-dimension line scan method to detect an exact position of lane.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.177-177
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• 2000

In this paper, we propose a two-input two-output fuzzy controller to improve the performance of transient response and to eliminate the steady state error. The outputs of this controller are the control input calculated by position-type fuzzy controller and the accumulated error scaling factor. Here, the accumulated error scaling factor is adjusted on-line by fuzzy rules according to the current trend of the controlled process. To show the usefulness of the proposed controller, it is applied to several systems that are difficult to get satisfactory response by conventional PD controllers or PI controllers.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.1
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• pp.52-62
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• 2013

In order to obtain the relation between the cutting force and the process parameters in the chamfering process for the gear of a gear shaft, analysis of the process was performed with a simplified model instead of considering the whole actual 3-dimensional cutting situation produced between cutting tool and gear. The model divided the actual situation into the accumulation of hundreds of 2-dimensional layers with a small thickness in the direction of the height of gear and derived cutting force at a cutting position by accumulating each cutting force calculated in a layer. With proposed method to analyze the cutting forces in the chamfering process, it was revealed that the cutting position and size were exactly searched to calculate the cutting force in each layer. The total cutting force was the highest in the corner where the cutter encountered the gear first during the relative motion between them. The cutting forces were changed in proportion to the cutting parameters such as feed rate and trajectory.