TPT May 2022


QASS and Bültmann introduce fully automated tube chatter marks solution

The key to success is to monitor the machine with microsecond accuracy. The solution from QASS uses piezo-

electric sensors, which detect early vibrations of the mandrel as a sequence of rapidly occurring micro-pulses before the damaging chatter occurs and become visible on the tube. Due to the steady communication with the Bültmann machine control via PLC or BUS communication, QASS can ask to reduce the drawing speed (done in intervals of 25 per cent and 50 per cent) at any point during the process. Other key features of the QASS software are effective noise filters to separate the micro-pulses from ambient production noise and a fully customisable human-machine interface allowing the user to fine-tune the detection sensitivity.

IN COOPERATION with Bültmann, QASS has developed a fully automated solution to avoid chatter marks. Chatter marks are a well-known quality issue in the field of tube drawing. They are caused by the mandrel vibrating up to resonance, which leaves visible marks on the surface of the tube. When chatter occurs, the machine operator manually reduces the drawing speed to attenuate the shaking tube – by reducing the drawing speed with a potentiometer. To avoid chatter marks, the current best practice is to operate the machine well below its maximum drawing speed, and therefore, it is not utilised optimally. A drawing machine equipped with the QASS system can operate at significant ly higher drawing speeds. Specifically, customers have increased the drawing speed by 80 to 120 per cent while reduc ing the frequency of rejects to less than one per cent of the drawn pieces.

The solution from QASS uses piezoelectric sensors to avoid chatter marks


Bültmann GmbH

• High resolution inspection of the entire surface


MAY 2022

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