Analysis of Resistance Cross Wire Welding with Pneumatic and Servomechanical Electrode Force FEM Calculations and 3D Model

Abstract

The article analyses the resistance cross wire welding of aluminium bars using the pneumatic and servomechanical force of welding machine electrodes. The analysis was performed in a numerical manner using the SORPAS software programme (model 3D). The calculations were performed for bars made of aluminium AA5182 and having a diameter of 4 mm. In terms of the pneumatic system, the analysis was performed for various values of welding current and electrode force. In addition, the analysis also involved such quantities as electrode travel, the static slope resistance of the welding area, the space distribution of welding power, energy supplied to the weld, the weld nugget diameter and the volume of metal. The calculations were conducted until one of the adopted boundary conditions, i.e. the maximum welding time (63 ms), the maximum penetration of bars (20%) or the expulsion of liquid metal was reached. The tests aimed to optimise the welding process by using the servomechanical electrode force system and the appropriate control of electrode force and/or travel. The tests enabled the obtainment of more convenient welding power space distribution where energy was concentrated in the central zone of the weld. As regards the pneumatic electrode force system, it was not possible to obtain the assumed nominal weld nugget diameter (> 1.9 mm). Instead, the ring weld was formed within the entire range of welding parameters. In terms of the servomechanical force system, the material was melted in the entire weld area and the complete weld nugget having the assumed diameter was obtained. The FEM calculation results were analysed and presented graphically using the STATISTICA software programme.