Modelling laser transmission welding of thermoplastic polymers and composites

热塑性聚合物和复合材料的激光透射焊接建模

• 批准号: 216935-2011
• 负责人: Bates, Philip
• 金额: $ 2.91万
• 依托单位: Royal Military College of Canada
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=638248
• 关键词: Modelling; laser; transmission; welding; thermoplastic

Laser transmission welding (LTW) involves mating laser-transparent and laser-absorbent parts. Laser energy passes through the transparent component and is absorbed near the interface between the two parts where it melts the polymer, allowing diffusion and ultimately welding to occur. In some cases, the high-temperature polymer melt can flow due to thermal expansion and/or pressure driving forces. However, the flow can also lead to internal stresses and weldline read-through which are often undesirable. High temperatures can also cause material degradation. These high temperatures are often mitigated by the extremely short exposure times generally associated with high-speed LTW. The research on melt flow would develop experimentally validated models for intentional and unintentional melt-flow during 'contour' and quasi-simultaneous welding using Comsol(R) software. This work is important as previous studies have shown that this flow is responsible for residual stresses at the weld interface that can result in visually unacceptable marks on the exterior surface. The degradation work would use techniques such as the Friedman and Flynn-Wall-Ozawa methods to assess the thermal stability of polymers as a function of temperature and time using thermogravimetric analysis. This data would be coupled with simulated temperature-time data from the thermal modelling of various LTW processes in order to predict material degradation at the weld. Exploratory studies in my research group suggest that this work is feasible. These modelling studies would be validated by experimental work that uses a Rofin-Sinar 160W 'contour' welding system and a new Bielomatik 200W 'quasi-simultaneous' welder. Materials such as unreinforced and reinforced polypropylene, polycarbonate and nylon 6 would be used in these studies.

激光透射焊接（LTW）涉及匹配激光透明和激光吸收部件。激光能量穿过透明部件，并在两个部件之间的界面附近被吸收，在那里它熔化聚合物，允许扩散并最终发生焊接。在一些情况下，高温聚合物熔体可由于热膨胀和/或压力驱动力而流动。然而，流动也可能导致内部应力和焊缝穿透，这通常是不希望的。高温也会导致材料降解。通常与高速LTW相关的极短暴露时间通常可以缓解这些高温。对熔体流动的研究将使用Comsol（R）软件开发“轮廓”和准同时焊接期间有意和无意熔体流动的实验验证模型。这项工作很重要，因为以前的研究表明，这种流动是焊接界面处残余应力的原因，可能导致外表面上出现视觉上不可接受的痕迹。降解工作将使用Friedman和Flynn-Wall-Ozawa方法等技术，通过热重分析评估聚合物随温度和时间变化的热稳定性。这些数据将与来自各种LTW过程的热建模的模拟温度-时间数据相结合，以预测焊接处的材料退化。我的研究小组的探索性研究表明，这项工作是可行的。这些建模研究将通过使用Rofin-Sinar 160 W“轮廓”焊接系统和新的Bielomatik 200 W“准同时”焊机的实验工作进行验证。在这些研究中，将使用未增强和增强的聚丙烯、聚碳酸酯和尼龙6等材料。