Grinding Ball Mill Drive Reducer - Gearbox Problem Prediction at Initial Stage

On January 22, 2024, at CMA, an increase in vibration was identified in the
Main Gearbox of the Calamine Mill, which until then had been in
normal operating conditions. The predictive team performed a detailed analysis to assess the health of the equipment and the need for intervention.

It was evaluated whether there had been any change in the operating conditions of the equipment, such as: feed rate, circulating load, water flow, power consumption, grinding media load, pinion temperature delta,
however, none of these parameters had significant changes that could contribute to the increase in vibration.

When performing the spectral vibration analysis, gear engagement stress and excessive clearance were identified in the bearings of the output shaft.

Immediately after the diagnosis and recommendation of the predictive report, the output pinion, bearings and seals were purchased, leaving the components available at the unit for intervention.

Contact was made with the gearbox manufacturer (Sumitomo) and the mill manufacturer (Metso) to verify the possibility of purchasing/borrowing a similar gearbox. However, none were available and it was reported that after a month of monitoring, on 22/02, the intervention on the equipment was carried out in a planned and scheduled manner, with the replacement of the items as recommended in the report.

The intervention was effective and prevented the gearbox from breaking, the vibration reduced from 14 mm/s to 1.5 mm/s, returning to normal operating conditions.

If the bearings had broken, the entire gearing, bearings and gearbox housing could have been damaged. As well as damage to secondary components such as the pinion and electric motor.

grinder mill reducer gearbox