Preventive vs. Predictive Maintenance: know the difference

Types of maintenance

Detective maintenance

Detective maintenance consists of methods that guarantee the safety and productivity of
equipment and installations. This type of maintenance works to ensure the long-term viability of this equipment
, contributing to its smooth operation.

Detective maintenance has similar objectives to predictive maintenance, which you'll find out about later on
. However, the purpose of detective maintenance is to locate possible hidden
signs that could lead to a breakdown. Tools for this type of maintenance include: annual vehicle inspection
, smoke and fire gas detectors, tests on all types of valves, control loops
for safety devices, inspection of fire and emergency pumps, ovens
and boilers, protection relays and electrical equipment.

During detective procedures, specialists check the system without
it ceasing to operate. This process makes it possible to detect hidden faults.
In this way, the specialist can correct the situation, keeping the system in operation.
The advantages of this maintenance include increasing the useful life of the equipment, improving
safety, reducing repair costs and controlling materials.

Corrective maintenance

Corrective maintenance tools, on the other hand, work when there is already wear or failure
in the equipment, replacing the affected parts and components. It is a set
of procedures aimed at correcting, restoring and recovering the production capacity of an
installation or piece of equipment that has suffered an alteration in its operation. Corrective
maintenance is a reactive management technique that waits for a failure to determine the
maintenance action to be taken.

When it comes to maintenance, corrective procedures are the most costly. This is due
to factors such as high equipment downtime, the high cost of stocks of
spare parts and low production availability.

Preventive maintenance

Preventive maintenance, on the other hand, encourages the possibility of failures and schedules machine repairs or
reconditioning. In this way, they reduce the likelihood of
breakdowns or degradation of the services provided. Preventive maintenance is an intervention that is foreseen,
prepared and programmed before a failure is likely to occur.

Preventive maintenance procedures include periodic lubrication, systematic overhauls
of equipment, instrument calibration and gauging plans, inspection plans
of equipment and the manufacturer's history or recommendations.

Predictive maintenance

Predictive maintenance is a methodology, i.e. a corporate philosophy, known
as a maintenance technique based on the condition of the equipment.

Predictive maintenance is the periodic monitoring of machinery, based on the analysis of data collected
through monitoring or field inspections. The main aim of predictive maintenance is to check
equipment on time in order to anticipate any problems that could lead to higher costs for corrective maintenance.

This type of maintenance indicates the real operating conditions of the equipment based on data on wear and tear or the degradation process. This procedure predicts the useful life of the components and the conditions for making the most of this time for the user.

Predictive maintenance aims to eliminate unnecessary dismantling for inspection,
prevent damage from increasing, increase the degree of confidence in the performance of a piece of equipment
or production line and reduce unplanned emergency work.

What is the best type of maintenance?

Now that you know about the different types of maintenance, you want to know which one gives
the best results, don't you? Between preventive maintenance and predictive maintenance,
we'll take the latter.

Predictive maintenance alone is able to anticipate the need for intervention in industrial parts and equipment
, prevent unnecessary replacement and disposal, avoid downtime of equipment
for repairs and increase the availability time of these machines, reduce costs on the company's
spreadsheet, increase the degree of confidence in the performance of the fleet and other equipment,
make the most of the useful life of all components, among other gains.

Predictive maintenance methods

Fluid analysis

One of the predictive methods is fluid analysis, with the aim of promoting the economical use of
lubricants, as well as correcting defects. Monitoring can indicate the right time to
change or renew the oils in equipment and its components. With modern machinery,
this type of analysis can be carried out quickly and very accurately.

This method regulates the degree of contamination and degradation of the oils, optimizing the time between
each change for the most economical use. Monitoring is carried out using a series of laboratory techniques that analyze solid particles generated by friction between parts, mixing with the oils.

These techniques determine the condition of each oil, indicating its degree of contamination.
The main properties observed during these procedures are the viscosity,
acidity and alkalinity indices, as well as the flash and freezing points. As for the degree of
contamination, the analysis focuses on carbon residues, metallic particles and water.

Structural analysis

Structural analysis, on the other hand, has the role of detecting the occurrence of cracks, fissures or bubbles in
equipment and its components. This is a significant predictive maintenance method. This monitoring
is of great importance, bringing together techniques such as echography, gammagraphy, interferometry
holography, radiography and ultrasound.

The data is collected periodically by the monitoring systems and analyzed by technicians who record all the information gathered for better predictive management. The time between each analysis is determined by the number of machines monitored and measurement points, the duration of use of the installation, the strategic profile of the machines and the material resources available.

Surface condition analysis

Another traditional predictive method used to monitor the degree of wear on equipment.
This is done by analyzing the surfaces of the parts, which degrade as a result of the friction produced
between them. This method can be done with a simple visual examination, using magnifying glasses or
without them, but there are several professional techniques for precise and detailed monitoring
of the condition of each part. Some of these procedures are: endoscopy, stroboscopy,
holography, molding and printing.

Study of vibrations

Finally, there is the study of vibrations. During operation, machines produce vibrations
which can gradually lead to wear processes.

By analyzing the evolution of the level of these vibrations, it is possible to gather information about the condition of the equipment. This measurement uses pickups applied to defined points on a machine in normal production service.

The device is known as a "vibration analyzer", with various models
portable and fixed. It can be used to detect faults in advance that need to be
corrected. These include faulty gears, misaligned couplings, inadequate lubrication,
among others.

Predictive maintenance and oil analysis

As we've already said, oil analysis is one of the most important predictive tools. Common
diagnostics based on oil analysis. The team responsible for predictive maintenance
of machinery and equipment can identify possible errors more quickly and even anticipate
them, avoiding compromising service performance or product quality.
Companies can only benefit from oil analysis. The useful life of components is extended. This reduces the cost of replacement materials, unnecessary oil changes and unscheduled maintenance work.

There are various types of oil analysis such as: contamination analysis, spectrometry,
physical-chemical analysis and ferrography. Find out more about each one.

Contamination analysis

With this method, it is possible to identify the presence of substances that could contaminate the
system. The oil can be contaminated by dust, wear and tear on the equipment or by
chemical reactions of the lubricant with other products. So, included in this category are
particle counting, water content, dilution and various other techniques.

Spectrometry

This oil analysis method identifies the chemical elements present in the lubricant. A
since the oil undergoes a combustion process and is disintegrated down to the atomic level. This
analysis is suitable for obtaining more precise information on wear, contamination and identifying
additives.

Physico-chemical analysis

It assesses the condition of the lubricant on a one-off basis or in periodic analyses. Here we can list
viscosity, acidity, basicity, oxidation and others.

Ferrography

It analyzes the particles found in lubricants to identify the degree and reason for wear
of machinery and equipment. It is listed here by tradition since, in reality, it is not
an oil analysis per se, but a machine analysis.

Oil analysis brings important benefits to the fleet. Carried out effectively, the procedure
anticipates situations where there is a risk of failure; avoids unnecessary downtime, increasing the availability
of machinery; reduces maintenance and stock costs and makes it possible to schedule
interventions and parts maintenance.

Predictive maintenance and cost reduction

As we always advise, companies that want to increase the useful life of their equipment
and reduce costs. They need to keep up to date with the predictive maintenance of their machinery. Assessing the
condition of this equipment requires meticulous data collection and analysis
of the equipment being monitored. Predictive maintenance is an essential tool in this context
.

The focus of predictive maintenance is always on reducing costs and increasing the availability
of equipment. The tools that make up the predictive maintenance process, such as
oil analysis. They help to detect anomalies in the equipment. Such as its state of wear,
in addition to reporting the presence of any contaminating substances in various components.
In this way, predictive maintenance enables something to be done before defects get worse.
Avoiding greater losses for managers.

Predictive maintenance allows actions to be taken at the right time. Avoiding
wear and tear on equipment or the loss of an important component as a result of
an unidentified or prevented fault. This also means that the machinery is
always ready for use and working at full capacity. For more productivity and
performance, increasing confidence in the equipment.

Conclusion

Each type of maintenance has its own purpose. With predictive maintenance, it is possible to anticipate the need
for intervention in parts and equipment. This reduces costs and
brings advantages to companies.

That's why it's important to know the objectives and processes of predictive maintenance. With it, you can
get the best out of your equipment, boosting its productivity. This series of techniques
extends the useful life of equipment.

And maximum control in the management of materials and resources, increasing the safety and credibility of the service provided. Reduce costs in your company with predictive maintenance. Talk to an ALS specialist.