Oil Analysis Case History - Power Press Bearing Fault

Applied Diagnostics Ltd - Precision with Pride

Introduction

This large industrial power press is monitored as part of a monthly Condition Based Monitoring programme. Vibration and Oil analysis is performed once a month to track the condition of internal press components, as well as the condition of the oil that lubricates the gears, rolling element bearings and gear bushes.

Oil Analysis Tri-Vector Results

The initial Tri-vector plot (June 06) raised concerns relative to Contamination and Wear within the oil, which prompted a closer inspection of the oil analysis results. Subsequent oil sample results periodically highlight contamination within in the oil.

*

Tabulated Oil Analysis Results

The following table breaks down the oil analysis results into 3 discreet groups, Wear, Contamination and Chemistry. By looking at the individual test results within these groups a better diagnosis can be made.

*

ISO Particle Count

The ISO particle count plots the number of particles of different sizes found in a standard volume of oil against a target cleanliness level. This test is particularly useful in alerting when an oil filter change is required.

*

Diagnosis / Conclusions

Following the initial baseline survey an inspection of the press bearings and gears was recommended. Increased clearances were found between the bronze gear bush and drive shaft. The internal surface of the bush was scored, which formed wear debris in the oil. Some surface damage to the gears was also noted. Poor oil condition was the most likely cause of the wear. Following the overhaul of the press both the Vibration and Oil readings returned to acceptable levels. Now when ever an oil samples highlights an ISO particle count alarm, the inline oil filters are changed. Since adopting this proactive maintenance strategy internal press damage has not occurred.

Internal Press Damage Detected

*