A new method for nondestructive quality evaluation of the resistance spot welding based on the radar chart method and the decision tree classifier

Abstract

To develop an effective nondestructive evaluation method for the welding quality of the resistance spot welding, the electrode displacement signal during the resistance spot welding process is monitored, and the acquisition data of the signal are innovatively presented as the radar chart format. Some geometric features of the radar charts are extracted to reflect the welding quality. The decision tree classification technique is adopted to build a classifier and to provide a visible and intuitive diagnostic procedure for welding quality assessment. Test results of the decision tree classifier show that it is feasible and reliable to evaluate weld quality based on the graphics features of the radar chart. The features and the weld quality are closely related, and their extraction avoids complex algorithm. Meanwhile, when there are small samples, the decision tree classifier can identify good or bad weld accurately and rapidly, even though the weld is from an abnormal welding process, such as expulsion, current shunting, greasy surface, and small edge distance condition.

Studies on the influence of process parameters on the AISI 316L resistance spot-welded specimens

“…Eshraghi et al [5] investigated the influence of resistance spot welding parameters on weld pool properties in a DP600 dual-phase steel: A parametric study using thermo-mechanically coupled finite element analysis was performed. Zhang et al [6] designed a visual and reliable weld quality assessment method for resistant spot welding. Zhang et al [7] elucidated the thermocompensated resistance spot welding (RSW) with a Zn interlayer to join AA5052-H12 (Al) aluminium alloy to AZ31B (Mg) magnesium alloy.…”

Use of projector based augmented reality to improve manual spot-welding precision and accuracy for automotive manufacturing

“…A coloured radial chart (similar to that proposed in [7]) on a transparent acetate was made to obtain the measurements accurately. Acetate was considered because it is inexpensive and is able to withstand the heat of the spot-welds.…”

“…A large portion of weld quality research has focussed to date on weld gun technology, such as resistive [7,8], gas metal arc [9] and laser [10] for manual operators, automated systems as used by manufacturing robots [11] and weld dynamics, such as spot-weld formations [12] and weld heat distribution [10,13]. However, not much research have been directed towards weld placements.…”

Connection Status Research of the Resistance Spot Welding Joint Based on a Rectangular Terminal Electrode

“…As an important connection method, resistance spot welding (RSW) has the characteristics of energy concentration, small deformation without additional welding materials, high production efficiency, and easy-to-achieve automatic control [1]. It is widely used in the production of automobiles and railways vehicles [2][3][4][5][6]. Conventional RSW generally adopts tapered or spherical electrodes to form circular welding nuggets [7].…”