We are in the middle of Industry 4.0. era.
The work environment, and not only, is increasingly … smart.
Smart means connected.
Connected almost always means automated.
Machines and robots become absolute protagonists in an automated environment.
The technician manages, programs, controls: this is the concept of “Human in the loop”.
Where there are machines, the maintenance topic becomes crucial, strategic.
Maintenance and efficiency
A machine neglected downtime risks. The downtime is one of the three main items of the Overall Efficiency Equipment. Therefore, the downtime has a crucial impact on the effectiveness of the production process.
Even more. Compared to the other two items, the speed of the process and the quality of the products that of the downtimes is the most critical item: a downtime can last a few seconds or a few hours, depending on the severity of the damage.
The machine maintenance topic, ever more advanced, connected and intelligent, is therefore a central item in a strategy that aims to pursue continuous improvement in productivity and quality.
There are four types of maintenance. We list them in order of increasing quality:
- Reactive maintenance
- Preventive maintenance
- Proactive maintenance
- Predictive maintenance
Reactive maintenance: the urgency triumph
The state of mind of a maintenance technician used to manage this type of prevention is similar to that of someone who is about to deal with a birth, is in the last days and is ready to leave, at any moment, for the hospital.
The maintenance technician is forced to keep the most common spare parts in stock: in a short time it is necessary to identify the problem, repair the equipment and restart it. Moreover, he must always be available and ready to face an emergency job.
- production is interrupted
- a machine failure can also have negative effects on the operation of other machinery
- it becomes complicated for maintenance technicians to manage and plan their time
Robert Golightly, AspenTech marketing director. “It has been shown that emergency maintenance can be five to ten times more expensive than maintenance activities performed on a scheduled basis.”
According to Deloitte‘s analysis, reactive maintenance is responsible for an OEE lower than 50%. To make a comparison, Deloitte classifies predictive maintenance bringing the OEE to a value above 90%.
Preventive maintenance: scheduled activities
In production it is absolutely normal to have to face scheduled machine stops.
This means that the equipment is subjected to maintenance at preset time intervals, repairing or replacing worn equipment before malfunctions. This strategy reduces maintenance costs. Replaced parts before malfunction may seem perfectly in place.
CIL (Clean Inspection Lubrication) is one of the tools able to perform preventive maintenance. The main purpose of CIL is to optimize machine downtime and reduce the frequency of severe faults. This type of maintenance involves the completion of simple, but periodic operations, performed by unskilled personnel.
According to Deloitte’s analysis above, preventive maintenance brings the OEE between 50% and 75%.
Proactive maintenance: problems identification
Proactive maintenance focuses on identifying the causes that could lead to breakdowns. For example, if an operator reports vibrations on a particular tool, the maintenance personnel can start working on the problem before it causes a machine failure or a breakage of an instrument.
The World Class Manufacturing methodologies include a tool specifically designed for this type of maintenance: the EWO modules and Machine Ledger.
The EWO module allows immediate evidence of warnings and malfunctions and facilitates the work of the maintenance technician in searching for the root causes of the problem.
The pro-active maintenance requires highly qualified personnel to correctly diagnose and solve problems on the basis of the alarm signals.
The virtue of a methodology like WCM is also that of having dedicated a pillar to the maintenance topic and therefore to have given the relative pillar leader the managerial power necessary to be able to stop a machine that seems to work properly; order parts that may not be apparently necessary and other executive actions.
Deloitte’s analysis shows that this strategy can lead to an OEE between 75-90%.
Predictive maintenance: anticipating problems
Predictive maintenance analyzes data to predict failures in advance, allowing changes to be made to production, planning and maintenance activities: this, to prevent breakdowns and avoid machine shutdowns.
Also in this case the most advanced World Class Manufacturing methodologies come to the rescue.
Let’s talk about Early Equipment Management.
The primary objective of EEM is to highlight the problems in the preliminary stages of the process, i.e. when it is cheaper to solve them.
It is a complex tool that ultimately includes other tools mentioned above, becoming a sort of maintenance hub. It can be linked to the Machine ledger, the Life Cycle Cost and FMEA (Failure Mode and Effect Analysis).
Deloitte’s analysis shows that predictive maintenance allows the OEE to exceed 90%.
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Source: Deloitte https://bit.ly/2JXiLE0
Ascoltando: Radiohead – “No surprises”
Lettura in corso: “Il piccolo Principe” by Antoine de Saint-Exupéry