When we think of high-volume manufacturing, we often imagine a smoothly running factory with every machine functioning perfectly to turn out finished products efficiently and in volume. For the people running such a factory, their objective is to keep the factory running at its optimal speed with minimal downtime. This objective recognizes every machine with moving parts suffers some wear and tear and will inevitably need to be serviced or have some parts replaced. The question is when is the best time to do this: do you do it according to a fixed schedule or do you wait for the machine to start showing signs of failure?
Approaches to maintenanceA first approach is to schedule maintenance tasks based on a fixed predetermined schedule, which ignores the actual condition of the equipment. Think of a regular car checkup at fixed intervals or mileage. This approach has the advantages of being simple to plan but also has significant drawbacks in that maintenance may happen too late, resulting in equipment damage and danger for workers, or it may be carried out when it isn’t necessary.
A smarter approach is Condition-based Maintenance. This approach drives maintenance actions based on the estimated condition of the machine that is typically monitored through inspection or using data from embedded sensors. This has the benefits that maintenance will happen before failure and only takes place when necessary, but the drawback is that maintenance only begins after the machine begins to show signs of failure and the necessary maintenance intervention may not be optimal for production scheduling.
A third approach is preventive maintenance. Here the aim is to predict, at the earliest point in time possible, the maintenance actions that will be required at some point in the future. It is an approach based on condition monitoring combined with a dynamic predictive model for failure modes. This has the advantages of optimizing maintenance to both the machine’s life and the factory’s production efficiency, although it does require a more complex overall system. (ST will be demonstrating a Predictive Maintenance application at IoT World, May 14-17 at the Santa Clara Convention Center in booth #504)
The primary promise of predictive maintenance is that it enables corrective maintenance to be scheduled at a convenient time while maximizing the equipments’ useful life by preventing equipment failures. With the knowledge of when machines need to be serviced and what needs to be done, maintenance work can be planned optimally with the right people and parts ready. This approach aims to eliminate unplanned line stops and reduce stoppage time overall. In addition to increasing the factory up-time, there are other advantages including a reduction in accidents associated with equipment failure and increased equipment lifetimes.
