• Transactions of Materials Processing
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• v.12 no.2
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• pp.128-133
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• 2003

In this study, the momentum conservation type punching mechanism for micropunching system was developed to avoid the punch failure in the misaligned status between the punch and die. The punching energy can be precisely controlled by the falling height of the projectile mass and the intermediata mass, which contacts with the punch, transmit the energy to the punch with the same contact condition. The potential energy of the projectile mass is converted to kinetic energy at the light weight punch that the projection speed into the sheet metal workpiece can be accelerated. The butt formation characteristics for the alignment condition and for the projection speeds are investigated to verify the feasibility of the proposed punching mechanism.

• The Korean Journal of Physiology and Pharmacology
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• v.9 no.3
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• pp.137-141
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• 2005

This study was undertaken to investigate the effects of [$D-Ala^2$, D-Leu^5$]-enkephalin (DADLE) on the spontaneous activity of medial vestibular nuclear neurons of the rat. Sprague-Dawley rats, aged 14 to 16 days, were anesthetized with ether and decapitated. After enzymatic digestion, the brain stem portion of medial vestibular nuclear neuron was obtained by micropunching. The dissociated neurons were transferred to a recording chamber mounted on an inverted microscope, and spontaneous action potentials were recorded by standard patch-clamp techniques. The spontaneous action potentials were increased by DADLE in 12 cells and decreased in 3 cells. The spike frequency and resting membrane potential of these cells were increased by DADLE. The depth of afterhyperpolarization was not affected by DADLE. The potassium currents were decreased in 20 cells and increased in 5 cells. These results suggest that DADLE increases the neuronal activity of the medial vestibular nuclear neurons by altering resting membrane potential.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1824-1827
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• 2003

The sheet metal shearing process is normally used in the precision elements such as semi-conductor components. In precision elements, burrs usually reduce the quality of machined parts and cause interference, jamming and misalignment during assembly procedures and because of their sharpness, they can be safety hazard to personnel. Furthermore, not only burrs are hard to predict and avoid, but also deburring, the process of removing burrs, is time-consuming and costly. In order to get the burr-free parts, therefore, we developed the precise burr measuring system using the laser. The laser burr measuring system consists of the laser probe, the photo detector, the achromatic doublet lens, and the rotary ＆ the X-Y table. In previous reports, we used simple vertical measuring method. But, as we used relatively bigger laser spot diameter and had the limited reflection angle, it was difficult to obtain the precise measuring results. So called, the spot size effect makes the profile of burr measured distorted and the burr height measured smaller. By introducing the novel laser measuring method which employing the achromatic lens system and the tilting mechanism, we could make the spot size smaller and get the appropriate beam direction angle. Through the experiments, the accuracy of the developed system is proved. The burr height measured during the punching process can be used for automatic deburring and in-situ aligning.