• Journal of Power Electronics
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• v.5 no.4
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• pp.305-311
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• 2005

Throughout the world, studies on the water energization are currently under way. Of those, Brown gas, which is generated through the electrolyzation of water and is a mixed gas of the constant volume of 2 parts hydrogen to 1 part oxygen, has better characteristics in terms of economy, energy efficiency, and environmental affinity than those of acetylene gas and LPG (Liquefied Petroleum Gas) used for existing welding machines. This paper analyzes the characteristics of Brown gas and presents methods for increasing the generating efficiency of Brown gas by designing a power supply to deliver power to a water-electrolytic cell and designing a cylindrical electrode to improve the efficiency of the electrolyzer needed for water electrolyzation. Based on the above the methods, a welding machine using Brown gas is developed. And the generation efficiency of Brown gas is measured tinder different conditions (duty ratio, frequency and amplitude) of supplied power.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.10
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• pp.45-51
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• 2010

Electrical discharge drilling (ED-drilling) is a widespread machining method used to bore small holes with a high aspect ratio. This paper presents additional methods by which ED-drilling can improve machining speed, tool wear, and machined surface quality. Firstly, for high machining speed, and low tool wear, a new-type electrode that was ground on one side or both sides of the cylindrical electrodes was suggested to expel debris. The debris which is generated during the machining process can cause sludge deposition and secondary discharge problems: major reasons to decrease machining speed. This new-type electrode also reduced tool wear that was due to the decrease of unstable discharge in a machining gap by helping to expel waste water and debris from the gap. Secondly, to improve the machined surface roughness, an electrolyzation process was included after drilling. This process made the machined surface smooth by means of an electrochemical reaction between an electrode and a workpiece. In this study, the machining speed, electrode wear, and surface roughness were improved by the newtype electrode and the electrolytic process.