| Summary: | 碩士 === 國立臺北科技大學 === 製造科技研究所 === 94 === The aim of this study is to develop a key technique of laser and scanning mechanism controlling in order to obtain a uniform property transformation depth, which leads to achieve the accuracy of precision casting.
For raising the quality of workpiece, a laser power feedback control system which could measure and compensate laser power, and a monitoring system which could measure the green part surface temperature were developed to obtain stable laser power and green part surface temperature. A self-developed raster scanning program could make laser scanning started at zone with constant scanning speed; therefore, workpiece could obtain uniform power density. The developed PWM laser controller was used for measure the length of accelerating a decelerating zone of X-Y scanning mechanism; it was helpful to achieve more accuracy scanning parameters and to integrate the raster scanning program to control system.
A single axis controller was developed and integrated to laser scanning platform for solving the problems of accelerating too slow and velocity unstable. Data from servo motor optical encoder was transmitted to a single chip for counting the motor moving distance. When the number of counting reached the preset value, laser controller would output a single square wave pulse for launch the laser; therefore, distance between each laser spot would be kept in constant. As a result, the power density was uniform distribution along the scanning path.
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