Page 395 - Intro Predictive Maintenance

386 An Introduction to Predictive Maintenance

First-line supervision is critical. Forepersons should spend most of their time manag-
ing their people at the work site and ensuring that customers are satisfied. It is not
possible to manage preventive maintenance from behind a desk. A foreperson must
get out and participate in the jobs as they are being done and inspect them on com-
pletion. This motivates people to do both high-quantity and high-quality work. The
foreperson will be on the site to apply corrective action as needed and to provide final
job inspection and close out the work order.

Avoiding Callbacks
“Callbacks” are generally defined as any repeat requirements for maintenance that
may result from problems that should have been alleviated earlier or that were caused
by earlier maintenance. Some organizations define a callback as any emergency main-
tenance on the same equipment within 24 hours for any reason. Other organizations
narrow their definition to the same problem but within periods as long as 30 days. A
measure should be chosen that suits the specific type of equipment. If your organiza-
tion services for pay, you certainly should not charge additional for callback service
because the problem should have been fixed the first time.

The fact remains that low-reliability people often service highly reliable equipment.
Preventive maintenance often incurs exposure to potential damage. The same steps
that improve quality assurance also reduce the incidence of callbacks:

1. Establish and follow detailed procedures.
2. Train and motivate persons on the importance of thorough preventive
maintenance.
3. If it works, don’t fix it.
4. Conduct a complete operational test after maintenance is complete.

Repairs at Preventive Maintenance
Two philosophies exist on the best way to handle repairs that are detected during pre-
ventive maintenance. One approach is to fix everything as it is discovered. The other
extreme is to repair nothing but rather mark it on the work order and ensure that
follow-up work orders are created. A policy that falls between the two is recom-
mended: fix the minor things that can be most quickly done while the equipment is
available, and identify other problems for separate work orders. A guideline limit of
10 minutes has proved useful to separate tasks that should be done at the time from
those that should be scheduled separately. Naturally, any safety problem that is found
should result in shutdown of the equipment and be repaired before the equipment is
operated again. Restricting the amount of repair done on preventive maintenance work
orders helps control these activities so they can stay on schedule. Table 16–3 outlines
the criteria to be considered for repair with preventive versus separate repair.

It can thus be seen that a small workforce with multiskilled persons servicing equip-
ment that requires long travel, has delay time to get on the equipment, and requires