Predictive maintenance enables maintenance to be carried out correctly and sufficiently without equipment failure by obtaining data from monitored equipment. According to research, reducing maintenance costs by 30% is possible with predictive and preventive maintenance.
Commonly accepted techniques for predictive maintenance include:
- Vibration control and analysis
- Oil analysis
- Thermography
- Ultrasonic measurement
- Non-destructive testing methods
- Monitoring of system variables (load, pressure, temperature, speed, current, voltage, flow, etc.)
Vibration Analysis:
As accepted worldwide, vibration analysis is the most crucial aspect of predictive maintenance. There are no limitations on which machines vibration analysis can be applied to, as long as the machine has a part rotating at least 6 RPM. Vibration analysis is a technique of examining the vibration magnitudes periodically (offline) or continuously (online) from machines using vibration measuring devices, by comparing them with specific standards. These values are determined by ISO. If the vibration values you obtain from your machine are below the limit values set by ISO, no corrective action may be necessary.
Four fundamental parameters are used to express vibration: velocity, displacement, acceleration, and frequency.
The goal of vibration analysis is to evaluate the data obtained at the end of measurements to alert maintenance services about the condition of the machine and to prevent unplanned downtime.
According to ISO 10816, the table below shows the machine condition based on the intensity of vibrations:
| MACHINE CLASS | MEASURED VIBRATION VALUES (Velocity,mm/sec) RMS * | |||
| Good | Mediocre | Mediocre | Danger | |
| Class1 | 0-0.7 | 0.7-1.8 | 1.8-4.5 | >4.5 |
| Class2 | 0-1.1 | 1.1-2.8 | 2.8-7.1 | >7.1 |
| Class3 | 0-1.8 | 1.8-4.5 | 4.5-11 | >11 |
| Class4 | 0-2.8 | 2.8-7.1 | 7.1-18 | >18 |
Class 1: Independent motors under 15 kW
Class 2: Flexibly coupled machines between 15-75 kW and rigidly coupled machines up to 300 kW
Class 3: Large rigidly coupled machines
Class 4: Large flexibly coupled machines
*This machine condition determination table is valid for the operating range of 600-12000 RPM and the frequency range of 10-1000 Hz.
Factors That Can Cause Vibration:
- Unbalance
- Misalignments in couplings
- Faulty bearings
- Deformed shafts
- Mechanical looseness
- Incorrect pulley adjustment
- Load and torque variations
- Friction
- Design flaws, etc.
