Contamination-free vibration welding for use in green technologies

马勒过滤系统公司(MAHLE)设计和制造各种内置式组件。Mahle目前使用振动焊接(VW)技术连接进气歧管中使用的注塑热塑性部件。为了扩展到燃料电池市场，MAHLE必须找到一种技术解决方案，以减少焊接过程中产生的颗粒污染的大小和数量。 大众涉及到在压力下将两个热塑性元件组合在一起。一个部件被阻止任何横向运动，而另一个部件以200赫兹的频率横向振动，幅度约为1毫米。在加工的初始阶段，库仑摩擦导致界面温度上升，最终达到聚合物的熔点。一旦形成熔融层，就会通过粘性耗散产生能量，导致更多的熔化。熔融的聚合物从焊接界面流动(这里称为闪光)，两个组分相互移动(这里称为熔融)。本项目将研究闪光灯的特性。大众汽车在行驶过程中产生的闪光通常比较易碎，可能含有“天使头发”等颗粒，这些颗粒可能会脱落，导致整车受到颗粒物污染。燃料电池市场对闪光污染的数量和性质有非常严格的要求。 该项目将确定热塑性材料参数、大众工艺条件以及焊接几何形状对闪光特性的影响。它将允许用户选择材料、工艺条件和焊接设计，以最大限度地减少颗粒闪光的形成。它将通过实验室测试、试点和工业规模的焊接和过程建模来实现这一点。

MAHLE Filter Systems (MAHLE) designs and manufactures a wide range of under-the-hood components. MAHLE currently uses vibration welding (VW) technology to join injection-moulded thermoplastic components used in air-intake manifolds. In order to expand into the fuel-cell market, MAHLE must find a technical solution to reduce both the size and amount of particulate contamination generated during the welding process. VW involves bringing two thermoplastic components together under pressure. One part is prevented from any lateral motion while the other is oscillated laterally at frequencies of the order of 200 Hz over amplitudes of approximately 1 mm. In the initial phase of the process, Coulomb friction causes the temperature of the interface to rise, ultimately reaching the polymer's melting point. Once a melt layer is formed, energy is generated by viscous dissipation causing more melting. Molten polymer flows from the weld interface (referred to here as flash) and the two components move toward each other (referred to here as meltdown). This project will study the characteristics of the flash. The flash generated during VW is often brittle and can contain particles such as "angel hair" that can break off resulting in particulate contamination of the assembly. The fuel cell market has very strict requirements on the amount and nature of flash-like contamination. This project will determine the effect of thermoplastic material parameters, VW process conditions as well as the weld geometry on the characteristics of the flash. It will allow users to select material, process conditions and weld designs in order to minimize the formation of particulate flash. It will achieve this through laboratory testing, pilot and industrial-scale welding and process modelling.