• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.10a
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• pp.74-74
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• 2003

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.9
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• pp.1144-1151
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• 2021

The pressing process is a compression process in which a product is made by applying force to a heated or unheated material to transform it into the desired shape. Due to the characteristics of press equipment that produces products through continuous compression for a short time, product defects occur continuously, and systems for solving these problems are being developed using various technologies. This paper proposes a real-time defect detection system based on an artificial intelligence algorithm that detects defects. By attaching various sensors to the press device, the relationship between equipment status and defects is defined and collected based on a big data platform. By developing an artificial intelligence algorithm based on the collected data and implementing the developed algorithm using an embedded board, we will show the practicality of the system by applying it to the actual field.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.80-85
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• 2016

Carbon fiber-reinforced composite materials have been widely used in various industrial fields, but there are limits to increasing their strength and stiffness, because of the short-length fibers that are impregnated in them. In this study, a lab-scale small extruder system was developed with the capability to perform the carbon fiber impregnation and extrusion process in order to evaluate the properties of long-length carbon fiber reinforced thermoplastic composite materials molded by the LFT-D method. Specimens were made with the small extruder to press-mold long-length carbon fiber composite materials and evaluate their material properties. As a result, it was found that the carbon fiber length, press load and carbon fiber contents have a considerable influence on the strength and stiffness. Additional studies on such factors as the mixing screw design and coating of the carbon fiber are needed in order to improve the mechanical properties of carbon fiber composite materials.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.10
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• pp.6977-6984
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• 2015

It is faced with the necessity of multi roll forming process of the ball slide rail which is made by adding the separate manufacturing processes, piercing, bending, trimming, to the roll forming process of a continuous plastic deformation, to improve the quality. However, the vibration and noise of the press machine in this process leads to the quality degradation of slide rail manufactured in this process. In this study, the roll was designed considering the optimal strain rates by the roll forming program with finite element method. And to estimate the static stability of the multi process the Von-Mises stress and deformation on the press was calculated with a structural analysis program. Also, to avoid driving systems in the resonance region their natural frequencies in the 1st and 2nd mode were calculated through the modal analysis. To verify its dynamic stability improvement the magnitudes of noise and vibration in the existing and studied system were compared using a microphone and accelerometers. And the widths and surface roughnesses of the rails which had been produced in the existing and studied process were measured. Therefore, it is known that multi roll forming process is stable in the analytical and experimental study.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.7
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• pp.865-873
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• 2013

The deep drawing and ironing (DDI) process involving the use of a high-capacity horizontal press is used for manufacturing acompressed natural gas (CNG) pressure vessel. However, some variables of the DDI process have been determined based on the experiences of workers, and the short die life needs to be improved for manufacturing the pressure vessel withhighquality and lowcost. In this study, process variables such as the draw ratio, distance between dies, radius of rounding of drawing die, and angle of ironing die are chosen to enhance the reliability and improve the die life based on previous studies and experiences. The draw ratio limits at which no tearing or wrinkling occurs are determined using FEA, and the distances between dies, radius of rounding of drawing die, and angle of ironing die are optimized by the DOE method. The results of the optimal process variables are compared with those of the existing DDI process for verifying their effectiveness.

• Journal of Life Science
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• v.27 no.7
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• pp.754-759
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• 2017

The 100 l culture system was made on the basis of LED light, and Nannochloropsis oculata was cultured in f/2 medium at light intensity ($100{\mu}mol/m^2/s$), culture temperature ($20^{\circ}C{\pm}1^{\circ}C$) and LD cycle (12hr). As a result, the maximum biomass of 1.07 g/l was cultured as a result of 100 l mass culture at $100{\mu}mol/m^2/s$ and 24 mg/l nitrate concentration in LED blue (475 nm). The extraction was carried out using sonicator, homogenizer and chemical method 0.5M HCl shredding method. The contents of chlorophyll a, chlorophyll b and carotenoid were 1.6, 0.5 and 0.3 mg/g cell. When using homogenizer, it was measured at 1.0, 0.6 and 0.2 mg/g cell. The chemical breakdown method of 0.5M HCl, chlorophyll a, b, and carotenoid contents were measured as 0.9, 0.8, 0 mg/g cell. The highest amount of biomass during the distruption time was measured at 3.6 mg/g cell at 15 min disintegration and acetone, 3.6 mg/g cell of acetone, methanol, and ethanol were measured as effective solvents. Concentration was measured by using microfilter, disk type continuous centrifuge and tubular type continuous centrifuge were 16.0, 1.1 and 0.5 g/l, respectively. Four kinds of equipment such as hot air dryer, vacuum dryer, spray dryer and freeze dryer were tested to optimize the drying process. As a result, the recovery rates of spray dryer and freeze dryer were 80% and 60%.