Two production lines (out of 10) provide more than half the plant’s revenue. Any time there’s a problem, those lines get prompt attention. Considerable effort has been made to reduce repair times. For example, some spare parts and special tools are kept in a locker near each line.
Additionally, each line has its own “specialist crew” consisting of two maintenance techs who are responsible for developing expertise in maintaining and repairing that line. Each wears a pager that the line’s supervisor calls when there’s a problem with the line.
Despite all this, these lines have excessive downtime. Why might that be?
With so much riding on these two lines (50% of revenue), the effort to reduce downtime is probably off-track. The focus is not on total downtime reduction, but on the speed at which operation can be restored. The spare parts and tools are examples of improving restoration speed.
When restoration speed is the focus, then shortcuts are taken to improve that metric. For example, it is usually faster to make a temporary repair than to perform a complete repair. If each repair is graded on how little time it took, then you’re going to have more incomplete repairs and thus a higher rate of downtime incidents.
A reliability assessment is a good place to start.