HeeJe Kim Pusan National University (South Korea) Jong-Han Joung Pusan National Univ. (South Korea) Dong-Hoon Lee Pusan National Univ. (Japan) Dong-Hyun C. Kim Pusan National University (United States)
In manufacturing processes, various and suitable pulse shapes are required for the purpose of materials processing, and the pulse shape is regarded as a dominant factor according to the specific property of materials. Therefore, this study has undertaken to generate the correct ones by using the two-pulse superposition technique. The pulsed Nd:YAG laser using a multi-mesh inductor L and capacitor C network and the pulse superposition technique is described. We have tried to superpose two pulses with the single shot multivibrator (SSM: 74LS123) having two silicon-controlled rectifiers (SCRs) which control the delay time of the two gate turn-on signals. One is a main rectangular pulse, and the other is a superposed sinusoidal pulse. The use of this technique might impart a number of advantages to people who need a suitable pulse shape for particular applications such as welding, cutting, and drilling. In addition, we compared the case of no superposition and applied input energy of 100 J in only the main circuit with that of superposition and applied input energy of 75 J in the main circuit and 25 J in the superposing circuit. It is found that the maximum efficiency of 4.5% is obtained within the range of delay time less than 230 µs by adjusting the delay time from 0 to 1 ms.