In the industry, maintenance and repairs of the machines and possible pause cost of the plantare quite costly. Due to an unexpected malfunction, the machines may be inoperable for a very long time. In this case, there is also an increase in production losses and cost in the companies that perform mass production. In the name of not stopping production, it has become a very important point in the cost calculations to determine the predictive maintenance methods that can be determined by using various test and analysis methods during the formation of faults.
According to the questionnaire studies, the companies that have been applied with the predictive maintenance methods have found the following benefits in their businesses;
Every produced machine produces vibrations in response to the force applied to the machine due to its assembly. These vibrations are converted to numerical values within the time axis using Fast Fourier Transform techniques. When any fault occurs, the error is manifested by specifying the differences in vibration values and exceeding certain threshold values.
In predictive maintenance, non-destructive examinations, vibration measurements and analyzes are usually performed, such as oil analysis, infrared thermography measurements, ultrasonic tests.
1) Oil Analysis
There is oil for the machines to work efficiently. With this oil and mechanical parts friction rises tominimum levels. If this oil quality shows a decline, the amount of oil on the machine parts is reduced by10 microns. After this point, wear and heating can occur due to rubbing. With the oil analysis method, itcan be determined how much wear or problem is in which part. Below the rubbing of the metals, lowviscosity is the main reason.
The viscosity is followed up periodically, the chemical values of the oil are monitored by looking at the oilproperties, and at the point where it starts to lose its properties, the machine is taken care of to changethe oil and remove the fault.
2) Infrared Thermography
It is used for tracking hot spots of the system. Infrared thermography is used in places where the temperature is quite high, such as power plants, ovens, heating systems. Temperature averages andchanges are monitored systematically and a temperature level is predetermined to stop any slowdownor operation of the system. If it is clear that the temperature is approaching the threshold level, a maintenance program is performed to intervene in the system.
3) Ultrasonic Test
It is one of the most useful methods in businesses. Assuming our hearing threshold is 20 Hz, the ultrasonic devices allow people to catch and separate the voices that we cannot hear. By following these voices, solutions can be produced for efficiency with regular reports. With this method, pressurized air leaks can be detected and steam trap tests can be used to detect bearing lubrication and damage situations.
4) Vibration Measurement and Analysis
The most common predictive maintenance method, vibration measurement and analysis can be used for every machine with rotating parts. Problems caused by machine design or assembly are a big handicap to find fault. Therefore, it is necessary to make measurements periodically and to correlate the obtained data. To do this analysis, the frequency and phase should be measured. Each of the machine parts produces different vibrations. In the event of a fault, it is possible to find out what the fault is and what part it is from when the usual frequency information is exceeded. Various software and devices are used to do these things.
In the maintenance process, if the machine malfunctions can be diagnosed early, it will be cheaper to perform maintenance and treatment, along with getting rid of the bigger problem that may arise in the future. Companies can take precautions on this issue too long. With this system, innovative opportunities are emerged for companies.