Aleris Aluminium, the German manufacturer of rolled aluminium products, is saving around 200,000 € a year by monitoring the condition of critical machine components on its rolling mill machinery.

The Koblenz-based company has installed two FAG DTECT X1 condition monitoring systems from FAG Industrial Services (F’IS, part of the Schaeffler Group). 16 sensors and two 8-channel DTECT X1 systems monitor the pedestal bearing on the bridle roller, 14 bearings on the deflector and flatness monitoring rollers, and 12 bearings and four gears in the mill pinion gears.

On four separate occasions, DTECT X1 detected damage to critical components at the plant. This enabled Aleris Aluminium to take the appropriate maintenance measures, preventing any unplanned machine stoppages. After installing the DTECT X1 systems, Aleris Aluminium has calculated the annual cost savings to be around 200,000 €.

The savings come from three main areas:

1. faster repair times and material savings on roller bearings, which amount to some 30,000 € a year
2. avoiding chatter marks was calculated to be worth a further 120,000 € a year, and 
3. the elimination of stand fires due to overheated roller bearings amounts to around 50,000 € a year.

In addition to this, F’IS is also providing remote condition monitoring services to Aleris Aluminium via two GSM wireless modems, one on each DTECT X1 unit. Evaluation of the condition monitoring data is carried out by F’IS experts at its Diagnosis Centre in Herzogenrath, Germany. Any irregularities are immediately evaluated and reported, along with any recommended remedial action if required. Aleris Aluminium receives a monthly report from F’IS on the condition of the monitored machines, which are guaranteed for a minimum warning time of four weeks before any failures.

The system also monitors strip speed (conversion to roller and gear speed) and motor current (load). The DTECT X1 series is a cost effective range of online monitoring devices that enables permanent frequency-selective monitoring. The advantage of this system is that it includes features that are usually only available in far more expensive online products.

The basic model is available as a 2-channel or 8-channel version with external multiplexer. All commonly used acceleration, speed and displacement sensors can be connected to the system. Depending on the version used, process quantities such as speed, temperature, torque and pressure can be recorded. The signal measured by the sensor is broken up into its frequency components using Fast Fourier Transformation (FFT), which enables monitoring of amplitudes for previously specified threshold values within very narrow, defined frequency bands, including the triggering of an alarm if these values are exceeded. Therefore, damage can be detected at an early stage by means of frequency-selective monitoring.