MASTER Welding Control
MASTER is based on the principle of the calibration welding operation. During the calibrating welding operation, the welding current is maintained at a set constant level. A good weld joint is attained without disturbances and with optimum settings for welding time, welding current and electrode force. The welding current and electrode voltage data which are measured during this welding operation are stored. After switching to MASTER control mode, all subsequent welding operations are controlled in accordance with the stored MASTER calibration data.
These control processes inevitably necessitate fast welding current sources. This requirement is fulfilled by medium-frequency inverters with a response time of 1 millisecond - at an inverter frequency of 1,000 Hz - and by the substantially faster high-frequency inverters at an inverter frequency of 20,000 Hz. Thyristor controllers with a response time of 10 or 20 milliseconds are too slow for many welding applications.
MASTER is sensitive to:
- mains voltage fluctuations
- electrode wear (automatic stepper function)
- electrode force fluctuations
- small edge distances
- welding splashes
- changes from 2-sheet to multiple sheet welds
The MASTER control process compensates the various influencing factors by increasing or reducing the current strength and extending the welding time. Extension of the welding time can be limited.
Welding splashes are monitored via output of an error message, with optional shut-down of the welding current.
Optimum adaptation to each weld spot guarantees that the required strength for weld joints is maintained troughout broad ranges.