环形激光束形成及高分子材料焊接性能的研究

Formation Principle of Ring Laser Beam and Research on Laser Welding of Polymer Materials

利用光纤激光研究了环形激光束的形成原理,并利用环形激光束实现了高分子材料的超高速焊接。试验结果表明,随着准直镜焦距的增加,环形激光束的外径不变,内径减小,环形激光束的光环宽度增加;随着第一枚圆锥透镜和第二枚圆锥透镜的间距L12增加,环形激光束的内径和外径同时增加,而环形激光束的光环宽度几乎不变;通过准直镜、第一枚圆锥透镜及第二枚圆锥透镜的同轴性调节,可获得能量密度分布均匀的环形激光束;利用外部直径为54 mm、内部直径为47 mm及宽度为3.5 mm的环形激光束,对厚度为(2+1)mm的高分子材料搭接接头实现了超高速焊接。当试验压力为100 N,激光输出功率为800 W,焊接时间为0.6 s时,高分子材料焊接接头拉伸剪切性能与母材相同,其拉伸剪切断口位于母材(TPV-弹性体)上。

A ring beam optics is developed for a circular seam welding of the automotive using a fiber laser, and the polymer material with a circular seam are firmly welded in a super-short time. As the results, with increase of focal length of collimating lens, the outside diameter of the ring laser beam is hardly changed; the inside diameter of the ring laser beam decreases; the width of the ring laser beam is increased in the experiment. Distance（L12）between the first axi-cone lens and the second axi-cone lens increases, the outside diameter and inside diameter as the ring laser beam increases simultaneously, and the width of the ring laser beam is almost fixed. Moreover, it is confirmed that the intensity distribution of the ring beam becomes uniform by adjusting the coaxial performance of collimating lens, the first axi-cone lens and the second axi-cone lens. The ring laser beam has been outside diameter of 54 mm, inside diameter of 47 mm, and width of 3.5 mm, performing the high speed welding of lap joints in the（2＋1） mm thickness of polymer material. When pressure is 100 N, laser power is 800 W and irradiation time is 0.6 s, the tensile-shear strength of the polymer material joint with laser welding is approaching to the base metal,whose fracture of the stretching pieces is appeared in the base mental（TPV-elastomer）.