Analysis of the Heating Behavior and the Strength of Hot Gas Welded Polyamides with 3D Contours Using an Immersing Nozzle System

With the help of computational fluid dynamics (CFD) simulations a nozzle system (top nozzle system) for hot gas welding, which encloses the weld seam during heating, was developed. The significantly more controlled flow behavior of the hot gas improves the processing window, increases the reproducibility and achieves a more efficient heating of the polymer weld seam with inclination angles up to 60°. The heating behavior and weld strength are investigated on three types of plate specimens with varying inclination angles. The investigations are carried out on a series-production hot gas welding system with PA6-GF30 and a PA66-GF35. Stainless steel additive manufactured top nozzle systems for 0°, 15°, 30°, 45° and 60° inclination angles are tested. With the optimized top nozzle system, weld seams with inclination angles of up to 60° can be reproducibly joined thanks to the wide processing window without a significant reduction of the component strength.