What are the types of failures and how do they evolve into breaks?
Failure is characterized by the equipment’s inability to perform its required function, it is considered an event. On the other hand, the break is different because it is the state in which the equipment is.
In other words, it is possible to find a device with a failure event without being prevented from functioning. While the breakdown, it would be the state of disuse of the equipment until it is repaired.
Therefore, maintenance aims to identify failure events so that they can be repaired before progressing to the state of equipment breakdown.
With this, failures can be classified by their period of incidence at 4 different moments:
The evolution of failures to breakage also occurs in 4 stages, namely:
- Hidden Failure: When the operator cannot recognize or visualize the problem. At this stage there is still no apparent damage to the equipment’s operation;
- Potential failure: there are signs of loss of standard equipment performance. This is especially when predictive maintenance is applied. Performing benchmarking analysis to identify the failure before it moves to the next stage;
- Functional failure: when predictive maintenance is not performed, or not performed correctly, the failure proceeds to this stage. This is where the equipment is unable to perform its functions as expected for production;
- Total failure: At this stage, if nothing is done in the previous steps, the equipment is completely broken, and with that, it is necessary to act with corrective maintenance.
Therefore, it is clear that many serious failures and breakdowns do not occur suddenly and can be prevented with predictive maintenance. Either in the first moment and stage or in the subsequent ones before the break.
What are the types of maintenance and their benefits?
There are 3 types of maintenance, namely:
- Preventive Maintenance: procedure carried out to avoid equipment to be outdated, mitigating the occurrence of industrial failures;
- Predictive Maintenance: inspection and analysis of equipment data to determine when and which maintenance process to perform;
- Corrective Maintenance: the one with the highest financial cost, carried out urgently to correct equipment breakage, minimizing impacts on the production line.
In order to carry out preventive maintenance, the equipment supplier usually provides instructions on when and what to do. As a result, predictive maintenance complements this information with real-time equipment analysis, ensuring greater safety at the factory.
Corrective maintenance, on the other hand, happens when even with the application of other maintenance or due to the lack of it, there are failures and the breakdown of the equipment. As a result, it becomes more expensive both for the materials used and for the loss of productivity in the factory.
Therefore, the main benefits of maintenance are:
- Risk and failure reduction:
Applying maintenance procedures correctly prevents problems from occurring unexpectedly with equipment, which affects the entire production;
- Extending the useful life of machinery:
Ensuring through maintenance that all equipment components are operating as expected is the best way to make the machine operate well and stay that way for a longer period;
- More time to make better price search for new purchases:
With the early identification of problems or possible failures, it is possible to search the market for the best prices and suppliers for replacement parts. Thus, when a failure compromises the machine’s operation, it can be replaced immediately;
- Better ability to meet demand:
Predictability, with mitigation of impacts from failures and breakdowns, allows the factory to bring results as expected, or even better.
And what are the indicators to assess the reliability of equipment?
There are two main performance indicators for industrial equipment, which are related to the availability of equipment in operation:
- MTBF (Mean Time Between Failures): The longer the time between failures, the greater the reliability of the equipment;
- MTTR (Mean Time To Repair): This value must be as low as possible, after all, it is not a good thing that a device is not working for quite some time.
Thus, reliability indicators are an evolution of maintenance indicators and provide a high level of quality for the industrial sector.
By measuring the mean time between failures it is possible to predict when the next failure will happen. And as a consequence, the availability of equipment. This is possible through the use of historical data to make assertive projections.
The MTBF calculation is performed using three variables:
- Real uptime: ideal time the machine would work if it never needed maintenance;
- Total maintenance time: time the machine was down due to failures and repairs;
- Number of stops: number of times the machine has stopped.
By measuring the repair time, it is possible to estimate the time that the maintenance team needs to repair the equipment.
For this calculation, only two of the three variables described above are needed, namely: Total maintenance time and the number of stops. With this calculation, it is also possible to measure the efficiency of the maintenance team.
MTBF and MTTR indicators in the industry
It is not new that MTBF and MTTR indicators are used in the industry, as they have been a reference for management decisions, efficiency, and productivity measurement for over 60 years.
Thus, by measuring and periodically monitoring these indicators, it is possible to determine a relationship between them and identify scenarios for improvement. Always with the objective of carrying out preventive maintenance, preventing the equipment from being stopped due to damage caused.
This applies especially when we talk about Industry 4.0 more and more, as the control of these indicators becomes essential. This happens because the indicators directly support the efficiency and productivity of the entire industrial plant.
With all of this, how can one develop an inspection route plan?
The route plan is intended to systematize the maintenance activities that must be carried out with a frequency defined by the needs of the industrial plant.
It is carried out based on the importance and criticality of the equipment in the factory’s production process. With the objective, of course, of avoiding or mitigating failures and breakdowns in the production line equipment.
Here are the 4 steps to carry out an inspection route plan:
- Define the activity to be performed;
- Define the frequency of the activity, considering the frequency of use of the equipment, history of operation and failures, and the impact that the asset has on the production process;
- Define who will carry out the planned activities and the time required for them to be done;
- Define which equipment will be inspected and at which specific points, if any.
Therefore, following these steps, you can considerably reduce the cost of equipment in your factory, in addition to providing greater productivity!