Optimal Parameters Analysis of Fiber Laser-Induced Color Marking by Taguchi Method

• Main Authors: Yung-Chin Lin, 林永欽
• Other Authors: Chin-Lung Chang
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/06447913880158334443

碩士 === 國立屏東科技大學 === 車輛工程系所 === 101 === The purpose of this thesis is to obtain the color marking using YVO4 fiber laser and scan head and to investigate the optimal process parameters of fiber laser-induced color marking by Taguchi method. First, the experiment was set with different processing parameters, such as laser power, scanning velocity, pulse frequency, line spacing and marking times. Then the marking process parameters was optimized and only to consider the laser power, horizontal overlap rate and vertical overlap rate to investigate the marking process. After that, the bright and saturated colors on stainless steel surface were expected to achieve with the optimal parameters by using Taguchi method with gray relational analysis. Finally, optical microscopy and spectroscopy GER 1500 were used to observe the surface colors and reflectance on the specimen. Experimental results showed that the different sets of process parameters will make the stainless steel surface absorb different laser energy and form the oxides of different thickness or compositions, which is leading to demonstrate different marking colors. Once the process parameters was optimized, the horizontal overlap rate varied from 83% to 97% and the vertical overlap rate from 83% to 97% with 5W laser power, a regular color variations can be achieved. Furthermore, when the process was not be optimized, the obtained average radius of the red, green and blue colors in the analysis of the xy chromaticity diagram is about 0.0494. However, after the parameter optimization process by Taguchi method with gray relational analysis, its value is approximately 0.1072 in the analysis of the xy chromaticity diagram. Obviously, the brighter and saturated colors can be effectively obtained by Taguchi method and gray relational analysis. Moreover, from the observation of optical microscope, a smoother surface will be obtained by using optimal process parameters and will lead to a well-mixed color distribution. Finally, through the color reflectance analysis by spectrometer measurements, we can get that red color at wavelength 600 nm ~ 650 nm band has a 65%, green color at wavelengths 475 nm ~ 525 nm band 45% reflectivity, and blue color at 400 nm ~ 450 nm band 65% reflectivity. Compared with the theory value of reflectivity for trichromatic colors, the reflectivity values were very close at primary color waveband. Although, the reflectivity have a higher value on stainless steel surface in the non-primary wavelengths due to doping effect of other colors and the polishing effects.