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Predictive maintenance at Nexa generates a saving of R$ 673,000.00 and 18 days of production

March 25, 2024

Dynamox’s predictive maintenance solution allows clients to often replace corrective interventions with planned interventions, saving time, productivity, and money. This is what happened in another Nexa success case, which relies on an excellent team in its AMC (Asset Monitoring Center) combined with the Dynamox solution.

Predictive maintenance - Dynamox solution - Nexa asset

In Vazante/MG, Nexa’s main reducer in the calamine mill was operating under normal conditions. However, its vibration levels were increasing, reaching alert level A1 (attention) on the Web Platform on 01/22/2024. On this date, Nexa’s predictive team conducted a detailed analysis of the asset’s health.

Reducer – RMS Velocity

 Dynamox Solution - Nexa Reducer

During the analysis, an assessment was made to determine if there were any changes in the operating conditions of the equipment, such as: feed rate, circulating load, water flow, power consumption, grinding media load, and pinion temperature data. However, none of these parameters showed significant changes that could contribute to the increase in the reducer’s vibration.

Upon analyzing the vibration spectrum, it was identified that there was excessive gear stress effort and backlash in the bearings of the output shaft.

Spectrum – Main Reducer

Dynamox solution - Spectrum

Acceleration spectrum showing a high amount of modulations in the output rotation frequency of the reducer.

Waveform – Reducer

Dynamox solution - waveform

Waveform graph – Autocorrelation

Dynamox solution - Wave autocorrelation

Circular autocorrelation with 58 divisions, representing impact peaks on the output shaft gear of the reducer.

 Dynamox solution - peak to peak

Linear elevation in peak-to-peak acceleration. After intervention, the equipment is in normal condition according to vibration analysis.

Immediately after performing the predictive report with the diagnosis, the Nexa team purchased the output pinion, bearings, and seals, making the components available at the unit for intervention. Additionally, on January 25th, an equipment inspection stop was carried out, where superficial and premature wear of the output pinion was identified.

Predictive maintenance - Dynamox solution - Nexa image - failure

Following the evolution of the problem through the graphs on the Web Platform, after the vibration levels reached alert level A2, Nexa’s planned intervention day (02/22/2024) arrived. At this point, the team proceeded with the replacement of the items indicated in the report (output pinion, bearings, and seals).

Dynamox solution - RMS velocity failure

The maintenance team’s work was efficient, and the effective intervention prevented the reducer from breaking, reducing its vibration from 14 mm/s to 1.5 mm/s, returning it to its normal operating conditions.

 Dynamox solution - RMS velocity post-intervention
Manutenção preditiva - Solução Dynamox - imagem Nexa

If there hadn’t been a planned intervention and the bearings had broken, all the gearing, bearings, and casing of the asset could have been damaged. Additionally, there could have been damage to secondary components such as the electric motor and pinion.

Dynamox Solution – Predictive maintenance

Here’s a comparison between the planned intervention that occurred and how it could have been in the opposite scenario, relying only on corrective intervention:

PlannedCorrective
Bearings, seals, and output pinion: R$ 77,000.00New reducer: R$ 750,000.00
Labor: R$ 70,000.00Labor: R$ 70,000.00
Production loss: 1.9 daysProduction loss: 20 days

So, the Nexa team, along with the Dynamox solution, achieved a savings of R$ 673,000.00 and 18 days of production. This was another excellent success case. Therefore, we congratulate the predictive maintenance team of the mining company, represented by Arley Bruno, Flávio Rosa, and Lucas Maia, for their work.

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