Preventive maintenance, or preventative maintenance, consists of intervening on an equipment at regular intervals or according to predefined criteria. Its primary objective is to reduce the risk of breakdowns on assets, machines and equipment, but it also helps to achieve more general purposes. This is why most factories and companies are looking to increase the amount of preventive maintenance they implement as opposed to corrective maintenance.
To implement a preventive maintenance program, it is important to master the main aspects and to know which tools can be used. You will find all the answers to your questions below.
- What is the purpose of preventive maintenance?
- What is the difference between preventive and corrective maintenance?
- What are the different types of preventive maintenance?
- Why a preventive maintenance plan?
- How to create a preventive maintenance plan in a CMMS?
What is the purpose of preventive maintenance?
The primary goal of preventative maintenance is to limit the risk of malfunction and to reduce the number and frequency of machine failures. With this objective, we seek to:
- Reduce the frequency of production stops
- Reduce machine downtime for repairs
- Increase the life span of machines and equipment
- Predict corrective maintenance interventions in order to carry them out in the best conditions
- Better manage spare parts stocks
- Avoid unnecessary consumption of energy, lubricants and consumables
- Reduce the maintenance budget
- Improve the working conditions of the personnel
- Limit or even eliminate the causes of serious accidents
What is the difference between preventive and corrective maintenance?
To summarize, we can say that corrective maintenance solves problems while preventive maintenance seeks to avoid them. Thus, corrective maintenance, sometimes divided into palliative and curative maintenance, is performed when a failure occurs on a machine or equipment. Preventive maintenance seeks, through routine checks and tasks, to verify that an asset is functioning properly and to identify possible weaknesses in its functioning before it breaks down.
What are the different types of preventive maintenance?
There are 3 types of preventative maintenance:
- time-based or usage-based maintenance
- condition-based maintenance
- predictive maintenance
Time-based or usage-based preventive maintenance
Systematic preventive maintenance is important in terms of criticality concerning the first stages of degradation on a piece of equipment. With an efficient CMMS, it can be performed at predefined intervals, or according to a usage criterion, without taking into account the conditions of use of the machine. For example: changing a timing belt on a car every 150,000 kilometers, or changing a neon light every 7,000 hours of use.
Systematic maintenance requires a solid knowledge of degradation rules, such as the life curve of a ball bearing. It must be performed reliably, so as to eliminate any need for additional checks between two interventions or to avoid additional monitoring outside of inspection periods.
This type of maintenance is performed on equipment that does not require high parts replacement costs. This includes:
- Changing oil, bearings, seals, springs, contacts, resistors, lamps, etc.
- Adjustment of belt tension, pressure, potentiometers, etc.
- Control of levels, torque, etc.
The disadvantage of systematic planned maintenance is the need to determine the ideal maintenance frequency of the parts.
Condition-based preventive maintenance requires monitoring the operation of a machine, according to certain parameters (pressure, level, flow, etc.). The results of these controls are used to plan industrial maintenance operations.
This type of maintenance overcomes the disadvantages of systematic maintenance. It does not require any additional knowledge, except for the comparison of the controls with the predefined thresholds.
Condition-based maintenance can be continuous with a permanent recording of the measured parameters, or discontinuous with a periodic measurement of these parameters.
Predictive maintenance is carried out using estimates following analyses and evaluations of the machine’s parameters.
It is a high-cost type of maintenance, which requires sophisticated tools, and is only applied to elements that are critical from a safety and cost point of view. For example:
- Infrared thermography
- Vibration analysis (global and spectral)
- Oil analysis
- Non-destructive testing (NDT): ultrasound, dye penetrant testing, acoustic emission, eddy current.
To conclude, the three types of planned maintenance tend to reduce the probability of breakdowns, but do not prevent possible breakdowns between two interventions.
Why a preventive maintenance plan?
The use of a maintenance plan is essential to apply the principles of preventative maintenance. Indeed, planning is the key to respecting the procedures that allow anticipating and preventing breakdowns.
What is a preventive maintenance plan?
A preventive maintenance plan is a document that gathers the procedures, the resources and the schedule of maintenance interventions on an equipment or a machine.
A maintenance plan should be developed based on the following 3 criteria:
- the recommendations of the manufacturer of the machine concerned, which must be followed in order to apply the guarantee or quality assurance;
- the regulatory and normative provisions to which certain equipment is subject;
- the observations of users and maintenance technicians during the operation of the machine.
How to set up a maintenance plan?
To prepare a maintenance plan, it is strongly recommended to follow certain steps:
- determine the scope of intervention
- select the type(s) of preventive maintenance to be applied, and the corresponding interventions
- create a file containing all the planned interventions as well as all the information necessary to carry them out.
How to create a preventive maintenance plan in a CMMS?
In the next-gen CMMS software Mobility Work, the creation of a maintenance planning, for example, is very simple. You just have to :
- select the type of event to create
- choose the periodicity
- choose the number of repetitions
- select the equipment concerned
- select the assigned technicians
- add keywords to facilitate the analysis of the maintenance plan and provide information to users
- determine the deadline
- determine the expected downtime of the machine if necessary
- determine the expected time of intervention, in order to warn the production managers of the potential duration of the machine’s downtime
- add the necessary documentation, which will be available for consultation at each operation.
Afterwards, you will be able to easily visualize and manage your maintenance plans in your CMMS.