Resistance Welding of Sheet Metals

Welding of High-Strength Steels

The increased application of high-strength steels in the car industry causes a big problem in welding of sheet metals. Differences in the steel elasticity and the hardening of the sheets which has been caused by cold forming, result in poor fit-up and thus in increased sheet bulging which differ from part to part and occur even inside the parts; a determination before welding is not possible. Since, in most cases, sheet bulging is not compensated by fixing with clamps and pressure pads or similar tools, the welding gun is to provide the necessary force. Without adaptive welding current control, the compensation of the disturbance "sheet bulging" is, for all welding spots, managed through an extraordinary increase of the gun force only. However, the diameters of the welding spots which are located in the areas without sheet bulging are too small because the electrode force has been set too high. Instead of the electrode force increase, therefore, the application of an adaptive current control (adaptation of welding current and welding time) is the better solution of this problem.

Welding of Aluminium

Due to the lower resistance and the higher thermal conductivity of aluminium, the welding times must be shorter and the welding currents must be higher, compared with steels.

(Index figures: welding time: Al/St = ½; welding time should be < 200ms; welding current Al/St = 3/1)

As in welding of galvanised materials, the processing of aluminium entails the problem that the contact area of the copper electrodes is subjected to contamination. The accumulation with aluminium leads to deterioration of the conductivity and effects a considerable influencing of the heat generation and also the increase of the development of impurity layers till the electrodes are unserviceable. For the reliable welding of aluminium it is, therefore, imperative to avoid the impurity layer. This is carried out through regular cleaning of the electrode contact area by milling or brushing.

Our solution:

Power Units	Transformers	Operating Devices	Measuring Devices	Switch Cabinets	Software	Servo Drives	Gun Accessories
SPATZM300	SPATZTI-60R SPATZTI-120R	SPATZBG-02	SPATZ Multi04	AutoSPATZ CX / CXi	AutoSPATZ AS-01	ServoSPATZ M600LL M600LW	MASDAT
SPATZ M300plus	SPATZ TI-200R	SPATZBS-01		AutoSPATZ CX2i	AutoSPATZ AS-32	ServoSPATZ M800LL M800LW	Matlock
AutoSPATZ M600L				SilverSPATZ CLL-R	SPATZQS+	ServoSPATZGM	ServoSPATZGM
SilverSPATZ M600LL M600LW				SilverSPATZ CLL-R2	MASTER	ServoSPATZ WG50	ServoSPATZ WG50
SilverSPATZ M800LL M800LW				SilverSPATZ CLL-H1	MASDAT	ServoSPATZ WD20	ServoSPATZ WD20
AutoSPATZ M1600 M2400				SilverSPATZ CLL-H2		ServoSPATZ WD100	ServoSPATZ WD100
ServoSPATZ M600LL M600LW				SilverSPATZ HPA-H1
ServoSPATZ M800LL M800LW				ServoSPATZ CLL-R
				ServoSPATZ CXi
				SPATZAK
				DragSPATZAK