• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.371-374
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• 2003

The bending process for the "ㄱ" section product can be developed by the hot metal extrusion machine with the two punches moving in the different velocity. The bending phenomenon can be controlled by difference of velocity at the die exit section by the different velocity of billets through the two-hole container. The results of the experiment show that "ㄱ" section product can be bended by the extrusion process and that the curvature of the product can be controlled by the velocity of punch and that the defects such as the distortion of section and the thickness change of the product and the folding and wrinkling of the product did not happen after the bending processing by the extrusion bending machine.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.10a
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• pp.346-349
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• 2004

In the previous experimental study about extru-bending of angle product, the bending of extruded angle products with the '${\wedge}$' section and 'ㄱ' section can be abtained by the hot metal extru-bending machine with the two punches moving in the different velocity. The bending curvature can be controlled by the different velocity of billets through the two-hole container. This paper describes simulation of extru-bending process by the difference of punch velocities. The result of the forming simulation by $DEFORM^{TM}-3D$ shows that the bending phenomenon at the die exit during extrusion can be abtained by the two punches moving in the different velocity. And it is possible to design extrusion dies and to control the curvature of product through the simulation of extru-bending process by analysis

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.5
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• pp.1618-1637
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• 2014

Clustering wireless sensor network is an efficient way to reduce the energy consumption of individual nodes in a cluster. In clustering, multihop routing techniques increase the load of the Cluster head near the sink. This unbalanced load on the Cluster head increases its energy consumption, thereby Cluster heads die faster and create an energy hole problem. In this paper, we propose an Energy Balancing Cluster Head (EBCH) in wireless sensor network. At First, we balance the intra cluster load among the cluster heads, which results in nonuniform distribution of nodes over an unequal cluster size. The load received by the Cluster head in the cluster distributes their traffic towards direct and multihop transmission based on the load distribution ratio. Also, we balance the energy consumption among the cluster heads to design an optimum load distribution ratio. Simulation result shows that this approach guarantees to increase the network lifetime, thereby balancing cluster head energy.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.332-337
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• 2009

Recently, boss and rib test based on backward extrusion process was proposed to quantitative evaluate the interfacial friction condition in bulk forming process. In this test, the tube-shaped punch with hole pressurizes the workpiece so that the boss and rib are formed along the hole and outer surface of the punch. It was experimentally and numerically revealed that the height of boss is higher than that of the rib under the severe friction condition. This work is focused on the effect of the punch design and friction condition on deformation pattern in boss and rib test. From the boss and rib test simulations, it was found that there is slight variation in both the heights of boss and rib according to the length of punch land, nose radius, and face angle. However the hole diameter of the punch and the clearance between the punch and die have a significant influence on the heights of the boss and rib. In addition, the effect of flow stress was also investigated on the deformation patterns through FE simulations.

• Transactions of Materials Processing
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• v.18 no.8
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• pp.640-645
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• 2009

Recently, boss and rib test based on backward extrusion process was proposed to quantitatively evaluate the interfacial friction condition in bulk forming process. In this test, the tube-shaped punch with hole pressurizes the workpiece so that the boss and rib are formed along the hole and outer surface of the punch. It was experimentally and numerically revealed that the height of boss is higher than that of the rib under the severe friction condition. This work is focused on the effect of the punch design and flow stress on deformation pattern in boss and rib test. From the boss and rib test simulations, it was found that there is slight variation in both the heights of boss and rib according to the length of punch land, nose radius, and face angle. However the hole diameter of the punch and the clearance between the punch and die have a significant influence on the calibration curves showing the heights of the boss and rib. In addition, the effect of flow stress on the calibration curves was investigated through FE simulations. It was found that there is no effect of strength coefficient of the workpiece on the calibration curves for estimation of friction condition. On the other hand, the strain-hardening exponent of the workpiece has a significant influence on the calibration curve.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.4
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• pp.544-548
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• 2005

The objective of this study was to determine the effect of die temperature and dimension on extraction pattern, extract yield, and crude saponin content of extruded white ginseng. The extrusion variables were die temperature $(110\;and\;120^{\circ}C)$ and die dimension (3 holes with 1.0 mm, 2 holes with 2.0 mm, and 1 hole with 3.0 mm diameter). The browness and redness were indicator of active components in ginseng extract. Both were used to evaluate the effect of die temperature and die dimension on release pattern and release rate constant. Browness and redness of extract achieved its lowest value at die temperature $110^{\circ}C$ and 2 holes with 2.0 mm diameter, indicating the lowest extraction rate constant. Extract yield highly increased by extrusion treatment. Extract yield and crude saponin content were the highest at die temperature $120^{\circ}C$ and 1 hole with 3.0 mm diameter. In conclusion, extrusion process has contributed significantly in improvement of release rate of its active components.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.12
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• pp.1647-1653
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• 2011

The cycle time in injection moulding greatly depends on the cooling time of the plastic part that is controlled by cooling channels. Cooling channels are required to facilitate the heat transfer rate from the die to the coolant without reducing the strength of the die. Employing layered manufacturing techniques (LMT), a die embedding conformal cooling channels can be fabricated directly while conventional cooling channels are usually made of straight drilled hole. Meanwhile, H13 tool steel is widely used as the die material because of its high thermal resistance and dimensional stability. However, H13 with a low thermal conductivity is not efficient for certain part geometries. In this context, the use of functionally graded materials (FGMs) between H13 and copper may circumvent a tradeoff between the strength and the heat transfer rate. This paper presents a method for modeling of conformal cooling channels made of FGMs.

• Korean Journal of Materials Research
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• v.11 no.6
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• pp.441-447
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• 2001

A study on the TiN coating layer in small holes on the Purpose of die-casting dies application has been performed with a PACVD process. For the hole having diameter of 4 mm. the uniform TiN coating layer in the hole to the depth of 20 mm was achieved using DC pulsed power source. To understand the forming mechanism of TiN coating layer, plasma diagnosis on Ti, $N_{2}^{+}$ and A $r^{+}$ emissions was carried out during plasma coaling process by optical emirssion spectroscopy. When the duty ratio was equal or over 50%, the Peaks of Ti,$ N_{2}^{+}$ and A $r^{+}$ emission were obviously observed. While duty ratio was equal or under 28.6%, no peaks for Ti, $N_{2}^{+}$ and A $r^$ were observed and the formation of TiN coating layer was rarely observed. For the coating in 4 mm hole diameter, the coating layer with bipolar process was two times deeper than that with unipolar process.

• Design & Manufacturing
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• v.15 no.4
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• pp.65-71
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• 2021

In the early days of laser invention, it was simply used as a measuring tool, but as lasers became more common, they became an indispensable processing tool in the industry. Short-wavelength lasers are used to make patterns on wafers used in semiconductors depending on the wavelength, such as CO2 laser, YAG laser, green laser, and UV laser. At first, the hole of the PCB board mainly used for electronic parts was not thin and the hole size was large, so a mechanical drill was used. However, in order to realize product miniaturization and high integration, small hole processing lasers have become essential, and pattern exposure for small hole sizes has become essential. This paper intends to analyze the characteristics through patterns by exposing the PCB substrate through DMD and polygon scanner, which are different optical systems. Since the optical systems are different, the size of the patterns was made the same, and exposure was performed under the optimal conditions for each system. Pattern characteristics were analyzed through a 3D profiler. As a result of the analysis, there was no significant difference in line width between the two systems. However, it was confirmed that dmd had better pattern precision and polygon scanner had better productivity.

• Design & Manufacturing
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• v.9 no.1
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• pp.31-35
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• 2015

Recently, life expectancy increased in the development of medicine, the need for health has increased. Market for medical equipment is growing rapidly to an increase in the interest in health and aging worldwide. It is a device intended for ultra sensitive cleavage process of bone during joint replacement surgery on a technical advanced surgery, finishing, and hole. Domestic demand of the hand piece is a necessary condition on an ongoing basis. However, hand piece was made on the basis of the experience of many years in the country Japan, Germany, and the United States has spread to more than 90% domestic market. Feel the need for the development of the hand piece in the country, many companies are trying to in-house production hand piece. In an attempt to solve the problems with the hand piece of the present, in this paper, it was supposed to be a study of rechargeable hand piece to replace the existing pneumatic.