• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.3
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• pp.110-115
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• 2012

For domestic aircraft industry, not mass production of components is limited, small production scale of the order is made by part because many kinds of hundreds of thousands of kinds of small quantity batch production system are taking. But the high reliability and stability are required during the processing because they require high precision parts are required. It is found that when C-axis rotation speed was increased, the diameter of the cutting tool decreased with increasing surface roughness, while the turn-mail feed rate was increased with increasing the surface roughness.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.4_2
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• pp.605-613
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• 2023

The multi-axis combined machining technology has enabled combined machining, which was difficult. However, the reality is that manufacturing costs are rising due to expensive equipment and there is a shortage of machine operation engineers. The purpose of this research is to present the optimum cutting conditions for the surface roughness when processing the inner diameter of SUS440C, which is an egg material, using a CNC automatic lathe. As a result of measuring the surface roughness, dry machining was the best at R_a0.481㎛ at a spindle speed of 4,000rpm, a feed rate of 0.05rev/min, and a cutting depth of 0.3mm. In wet machining, the highest value was R_a0.317 at a spindle speed of 2,000 rpm, a feed rate of 0.05 rev/min, and a cutting depth of 0.2 mm. The lower the feed rate, the better surface roughness appears. It was found that the feed rate had more influence than the number of revolutions and depth of cut.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.406-409
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• 1997

An economical 4-axis CNC controller employing step motors is designed and implemented in this paper. By using the inherent ability of holding position of the motor, the CNC controller uses open-loop control for removing trajectory error and for a simple hardware. Each drive of axis has an 8-bit microprocessor 89C52 and a PC controls the axes and pendant by means of RS232C serial communication. Backlash is also compensated at the axis controller. While compensating the backlash, the feed rate becomes zero in order to minimize trajectory error. The trajectories of 16ms interval are computed on PC and are sent to motor drives. In the drives, the trajectories are linearly interpolated for 2ms interval. The developed CNC does not require add-on specific motion card on PC. From the experimental results, the validity of the CNC controller based on step motor is proved.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.4
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• pp.62-68
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• 2017

Since the aircraft parts industry is a high-value-added industry, mass production order production, and the hundreds of thousands. Therefore, parts produced However, since these parts require high reliability and stability, a high degree of precision is required. In Korea, there on the roughness of the machined surface in cutting process. However, research on the surface roughness characteristic obtained by which is widely used for aircraft parts is still insufficient in Korea. The purpose of this study is to investigate the effect of turning tool rotation speed and X axis feed rate on the surface roughness of cutting tools in CNC lathes during cutting of aluminum alloy 7075.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.11
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• pp.1529-1535
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• 2000

The aim of the present study was to determine whether brain corticotropin-releasing factor (CRF) and a new peptide, urocortin (UCN) have a direct action in brain mechanisms controlling feed, water and salt intake in sheep. We gave a continuous intracerebroventricular (ICV) infusion of the peptide at a small dose of $5{\mu}g/0.2ml/hr$ for 98.5 hrs from day 1 to day 5 in sheep not exposed to stress. Feed and water intake during ICV infusion of CRF or UCN decreased significantly compared to those during artificial cerebrospinal fluid (CSF) infusion. NaCl intake during infusion of CRF or UCN was the same as that during CSF infusion. Mean carotid arterial blood pressure (MAP) and heart rate during ICV infusion of CRF or UCN were not significantly different from that during CSF infusion. On the other hand, the plasma glucose concentration during ICV infusion of CRF or UCN tended to be higher than that during CSF infusion. These observations indicate that decreased feed intake induced by CRF and UCN infusion is not mediated by the activation of both the pituitary-adrenal axis and the sympathetic nervous system. The results suggested that brain CRF and UCN act directly in brain mechanisms controlling ingestive behavior to decrease feed and water intake, but do not alter salt intake in sheep.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.5 no.4
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• pp.318-331
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• 1995

The c - axis oriented single crystal of $LiNbO_3$ and $LiNbO_3$ : 5mol%MgO was success-fully grown by Floating zone method using halogen lamp as a heat source. The effects of the sintering condition of the feed rod and the atmosphere gas during the crystal growth on the be havior of the feed rod/melt interface were studied for growing crystal with the high quality, and then, the optimum growth conditions were determined by studying the experimental param eters, such as gas flow rate, pulling rate, rotation speeds of the feed rod and the seed. The grown crystals were analyzed using the chemical etching to observe the tch pattern and the ICP (Inductively Coupled Plasma) to determine the composition uniformity and the impurity content of Fe. The effects of additive (5 mol % MgO) on the transmittance and refractive index was, also, analyzed. In order to compare the nonlinear optical oharacteristics of $LiNbO_3$ with those of the other optical materials, the nonlinear optical refractive index ($n_2$) was calcu l lated using the measured refractive index.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.4 no.1
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• pp.57-62
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• 1994

$YbFeCoO_4$ single crystal was grown by floating zone method. The atmospheric condition of the growth was controlled in air and the growth rate was 1~2 mm/hr. After melting the feed rod of the composition of $YbFeCoO_4$, $YbFeCoO_4$ was decomposed to $YbFeCoO_4$ and CoO phase in the initial state of the growth. The liquid composition, however, changed to the direction of the eutectic point along the liquidus line and then stopped at the point in which $YbFeCoO_4$ single crystal could be grown. The growth direction of the crystal was preferred orientation [110], perpendicular to the c-axis in the hexagonal system due to using the polycrystalline seed.