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„Outstandingly consistent“

High-performance welding controller B 20K

With welding frequencies of up to 20 KHz, the B 20K welding controller offers a particularly wide range of options for high-precision current, power and voltage regulation. Features found nowhere else, such as the non-linear proportional adjustment, make this ultra-precise regulation possible and ensure optimally configured process parameters. This guarantees constant welding processes at uniform high quality – even when the process windows are extremely short.

Welding technology has long been one of the core competences of Otto Bihler Maschinenfabrik and the B 20K welding controller, which has been available since mid-2018, is the latest Bihler system designed specifically for resistance welding. In contrast to the B 5000, the B 20K is able to generate welding frequencies of up to 20 Khz. At this high frequency, the number of half-cycles is high – and so too, therefore, are the number of possible interventions. This permits particularly fast regulation and correction operations. The B 20K exploits this outstanding regulation capability in its many innovative features and functions. These include the five measuring channels which are integrated by default as well as the patented NC-controlled linear actuator. However, what gives the B 20K its particularly outstanding performance capabilities are its various newly optimized control and adjustment capabilities. For example, the B 20K possesses welding current or welding power control, partial RMS control and mains voltage control. The purpose of each of these control functions is to calculate the actual value of the dimension to be regulated in comparison to the nominal value and to regulate this to the setpoint value by adapting the parameters accordingly. Thanks to the four different control capabilities, it is possible to optimally adjust all the process variables for each welding task and achieve high, constant and uniform welding quality.

Free from overshoots

Unlike in conventional controllers, in the B 20K, the welding current and welding power, that is to say the fundamental process parameters, are adjusted particularly quickly and precisely thanks to minimized time lags. This is because the B 20K’s sophisticated off-state regulation cuts the time lag, also known as the idle time, by half. This is a newly developed feature which is unique worldwide. Another newly developed and unique feature takes the form of the non-linear proportional control which is implemented in the B 20K and depends on the current profile and output demands. In the case of small deviations, this produces a high amplification, while a small amplification is produced for large deviations. This algorithm prevents any control circuit overshoot despite the high control speed and control quality. In the B 20K, this ensures uniform, high welding quality – even in the case of exceptionally short welding processes of less than 1 millisecond. This is achieved by activating the partial RMS control feature which assists in welding current and output profile control. The control mechanism uses the characteristic current or output value for the last six produced parts and corrects the control of the next part prospectively in the light of these values. In particular, this provides the perfect way of countering process changes that occur over the medium or long term, such as gradual wear to the electrodes.

Optimized voltage protection

The mains power protection at welding currents greater than 20 KA is another important quality feature of the B 20K. This was recently further optimized and now provides even more reliable protection against mains voltage fluctuations. What’s new about this? The function compares the actual with the nominal mains voltage even before starting the welding job, calculates the corresponding correction value in advance and integrates this during ongoing control operation. This correction operation is then performed repeatedly during the welding process. In the case of welding currents below 20 KA, by contrast, the B 20K’s active power supply circuit provides secure, reliable protection against mains fluctuations. Taken together, all these control features make the B 20K the ideal welding controller for achieving optimum parameter settings and minimizing any disruptive influences.

Martin Ott
Head of Welding Technology

Tel.: +49(0)8368/18-340


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