The Numerical and Experimental of the Joining of Dot Matrix Printing Pin by Micro-Laser Brazing Method

• Main Authors: Yu-Chuan Lin, 林育全
• Other Authors: Yi-Cherng Lin
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/10149900092321153551

碩士 === 國立彰化師範大學 === 機電工程學系 === 91 === The purpose on this study is to braze the pin to the armature of dot matrix printer with the pulsed Nd：YAG laser. A three-dimensional printer needle finite element model has been setup to analyze the temperature field and thermal stress distribution in the process of laser brazing to find a better brazing condition. The experimental parameters designed include: laser power, spot size, pulse duration, focus position respectively. After brazing, the following tests were done including metallurgical analysis, micro-hardness, micro-tensile, micro-fatigue tests respectively. During the brazing process, the thermal cycle of armature was recorded to verify the result of finite element analysis. The study result shows that the laser peak power 600W, spot size 0.6mm, pulse duration 10ms, defocus-6.5mm, using type CF50-2 brazing paste can successfully join the pin to the armature. According to the metallurgic analysis, the type AISI-M42 pin and Fujitsu pin do not change its microstructure significantly during brazing process. In the micro-tensile test, the tension strength of type AISI-M42 pin is similar to of type Fujitsu pin. In micro-hardness test, the average hardness of type AISI-M42 pin is 7.84% less than of type Fujitsu pin. In the micro-fatigue test, fatigue limit of the AISI-M42 pin is 13.4% less than of the Fujitsu pin. In addition, the wetting ability of type CF50-2 brazing paste has better on the surface of the low steel sample with the same surface roughness. The numerical analysis result shows that the interface between the pin and the armature, and the region near the laser source both have larger thermal stress during brazing process.