【作者】 沈璇璇；

【导师】 王传洋；

【作者基本信息】 苏州大学 ， 机械设计及理论， 2011， 硕士

【摘要】 塑料的激光透射焊接具有焊件残余应力小、焊接质量好、易于控制和容易实现自动化等优点,被广泛的应用在汽车行业、微焊接等方面。国外有关塑料的激光透射焊接研究较多,产业化水平较高,但国内有关这方面的研究有限,且集中在高校和研究所,产业化很少。因此,开展塑料的激光透射焊接十分重要和必要。本文对聚碳酸酯(PC)和聚丙烯(PP)的激光透射焊接分别进行了深入研究,主要讨论激光功率、焊接速度和吸收剂碳黑含量对焊接质量的影响。首先,通过注塑实验得到焊接用试件。注塑件共有8种,分别为作为透明试件的纯PC、PP试件,以及作为吸收试件的三种不同碳黑浓度的对应材料试件。经过透光率实验测出了各试件对应激光器波长980nm的透光率,符合透射焊接条件。其次,根据正交试验设计方案进行了激光透射焊接实验,并对焊接成品进行了破坏性拉伸试验以及显微观测实验,得到了各组实验对应的拉伸强度及焊缝图片。通过分析得到,对PC和PP材料来说,激光功率是首要影响因素,其次是焊接速度,最后是碳黑含量,PC材料的最佳实验参数为激光功率40W,焊接速度40mm/s,吸收试件含碳量0.1%;PP材料的最佳实验参数为激光功率70W,焊接速度15mm/s,含碳量0.15%。最后,对PC材料的激光透射焊接过程进行了仿真模拟,得到了焊接速度和激光功率参数分别为40W、40mm/s,20W和50mm/s下的温度场分布云图,和对应的实验组23、4对比,得到的结果和实验结果较吻合。更多还原

【Abstract】 Laser transmission welding (LTW) of plastics has advantages of low residual stress, excellent welding quality, easy controlling and automatization. Thus, it’s widely used in many industries such as automotive and micro welding. LTW is the focus of research abroad, and has a large-scale of industrialization. However, in our country the related research is scarce and only done by the universities and institutes. Therefore, it’s very important and necessary to research on LTW of plastics.In this paper, LTW of polycarbonate(PC) and polypropylene(PP) were carried out separately. Influences of laser power(P), weld speed(v) and concentration of carbon black(CB%) as absorbent on welding quality have been discussed in details.First of all, welding specimens are obtained through injection molding. There are 8 kinds of injection molded parts in which pure PC and PP parts are used as transparent part in LTW, the corresponding parts with carbon black concentration of 0.05%, 0.1% or 0.15% are used as absorbent part. Transmittances of the 8 parts at 980nm(wavelength of laser device) are obtained in transmittance test which are all available in LTW.Then, LTW of PC and PP are carried out according to Orthogonal Experimental Design. Destructive tensile test and microscope snapshot are done after LTW, from which tensile strength and weld line photos are obtained. Through analysis we found out that for both PC and PP laser power(P) influences LTW most, followed by weld speed(v) and carbon black concentration(CB%). The best welding parameters for PC are listed as follows: Laser power(P) is 40W, weld speed(v) is 40mm/s and carbon black concentration is 0.15%.The best welding parameters for PP are 50W(P), 15mm/s(v) and 0.15%(CB%).At last, ANSYS software is used to simulate the temperature distribution in LTW process of PC. Simulations with parameters of 40W(P) and 40mm/s(v) as well as 20W(P) and 50mm/s(v) are calculated respectively which are corresponding to No.23 and No.4 of PC LTW. The results of simulations match well with the real experiments.更多还原