A Study on CO2 Laser Butt Welding of Plastics by Heat Transfer Control Using a Heat Sink

采用散热器传热控制的 CO2 激光塑料对接焊研究

基本信息

批准号：
17560175
负责人：
KUROSAKI Yasuo
金额：
$ 2.18万
依托单位：
The University of Electro-Communications
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

项目摘要

This report introduces a novel concept of CO2 laser welding of thermoplastics which is applicable to manufacturing medical appliances, micro-scale devices and the products requiring the smooth surface of welded region.The procedure has a few features: (1) to place a solid heat sink transparent to a infrared radiation beam in contact with an irradiated plastic to cool the surface during welding process, (2) to use no pigmentation or dye for radiation absorption enhancement, (3) to sustain thermal damage on the surface, and (4) to avoid the emission of harmful gas due to decomposition of plastics. The feasibility of the welding procedure for natural transparent plastics such as polyolefin and perfluoroalkoxy resins without any surface damage was examined using a CO2 laser (expediently diode laser) as a radiation source with a solid heat sink.By the numerical analysis of heat transfer in the objective model, it was confirmed that the cooling by fixed heat sink is effective for temperature reduction on the surface of the plastics, but it relatively takes much heat from there. In this method, it was proven that it could not be well heated deep within the thick articles. Then we tested the "pulse-irradiation": firstly, heat sink was set on the surface of the plastic during a certain irradiation of laser, secondly, heat sink was released and laser irradiate the plastic directly (This way was repeated several times). As the result, to prevent the thermal injury of the surface was the priority problem, the cooling by heat sink is moderately utilized and heat is supplemented with the direct irradiation in the short time for balanced temperature profile. This effect was confirmed by the experiment.

本报告介绍了一种新颖的CO2激光焊接热塑性塑料的概念，适用于制造医疗器械、微型设备以及要求焊接区域表面光滑的产品。该过程有几个特点：（1）放置固体热量对红外辐射束透明的水槽与受辐射的塑料接触，以在焊接过程中冷却表面，(2) 不使用颜料或染料来增强辐射吸收，(3) 承受表面的热损伤，以及 (4)避免因分解而排放有害气体塑料。使用CO2激光器（最好是二极管激光器）作为带有固体散热器的辐射源，检查了对聚烯烃和全氟烷氧基树脂等天然透明塑料进行无任何表面损伤的焊接工艺的可行性。通过客观模型，证实了固定散热器的冷却对于降低塑料表面的温度是有效的，但相对来说会从那里带走较多的热量。事实证明，这种方法不能很好地加热厚物品的深处。然后我们测试了“脉冲照射”：首先，在一定的激光照射下，在塑料表面设置散热片，然后释放散热片，激光直接照射塑料（这样重复几次）。因此，防止表面热损伤是首要问题，适度利用散热器冷却，并通过短时间的直接照射补充热量，以平衡温度分布。这一效果已被实验所证实。