At an appliance plant, the old maintenance procedures were being applied to a replacement, upgraded machine. Same process function, but not the same machine. The new one had an additional stage, and nothing on that stage was being maintained. This is an example of needing to add a task (or set of tasks).
In a different plant, a particular breakdown occurred repeatedly. The recommended maintenance was being done, but those who wrote the recommendations did not anticipate this failure mode. This is another example of needing to add a task.
In these examples, you could imagine a bit of a twist that would result in a “remove”. Suppose the new machine’s control system had solid-state hard drives instead of the Winchester type. You can remove from the PM the task of running a defrag utility; it isn’t needed with a solid-state drive.
One way to improve maintenance tasks is to reduce hazard exposure. For example, installing IR windows for thermography.
