脉冲光纤激光切割连杆裂解槽工艺参量优化

为了获得36MnVS4连杆裂解槽最优的切割质量，采用正交实验法对裂解槽进行了激光切割理论分析和实验验证，通过激光共聚焦显微镜测量裂解槽的深度、宽度、张角及曲率半径等几何尺寸，同时采用扫描电镜观测裂解槽底部微观形貌及热影响区的厚度，采用极差分析法得到了峰值功率、脉冲宽度、切割速率和脉冲频率对裂解槽几何尺寸的影响，并获得了最优实验参量组合。结果表明，裂解槽热影响区厚度皆小于100μm且裂解槽底部存在微裂纹及气孔，各参量组合对裂解槽宽度、张角及曲率半径的影响较小，对裂解槽深度的影响较大；脉冲宽度和峰值功率对槽深的影响较大，脉冲频率和切割速率对槽深的影响较小；优化后切割速率为1.0m/min，峰值功率为700W，脉冲频率为1000Hz，脉冲宽度为50μs。这一结果对实际生产具有重要意义。

Optimization of technology parameters for fracture splitting grooves of connecting rods fabricated by pulse fiber laser

In order to obtain the optimal cutting quality of fracture splitting groove on connecting rod made of new material 36MnVS4, experimental study and theoretical analysis of crack groove fabricated by laser cutting were investigated through orthogonal experimental method. Geometric dimensions such as depth, width, opening angle and curvature radius of fracture splitting groove produced by laser cutting were measured and calculated by laser confocal microscope, respectively. In addition, microstructure and thickness of heat affected zone on the bottom of crack groove were observed and measured by adopting scanning electron microscope. The effects of laser peak power, pulse width, cutting speed and pulse frequency on geometric dimensions of fracture splitting groove were analyzed by using range analysis method. As a result, the optimal parameter combination of cutting fracture splitting groove were found out. The results show that, the depth of heat affected zone on the bottom of crack groove is less than 100μm and there exist micro cracks and pores. The investigated parameters have less impact on the width, opening angle and curvature radius of fracture splitting groove, but have large effect on depth. Moreover, laser peak power and pulse width exert great influence on depth of crack groove, while cutting speed and pulse frequency have little effect on it. The optimal parameters exist with cutting speed of 1.0m/min, laser peak power of 700W, pulse frequency of 1000Hz and pulse width of 50μs. The study is of great importance for actual production.