What should a
company uses for a benchmark when
scheduling work orders?
At what point or timeframe do you cut off the schedule and call it "unscheduled"?
Answers or Advice:
- Scheduling may simply be based on the days of
the work week. Here's an example from: Youe maintenance planners meet with
their production counterparts on Thursday's to review the backlog
area. Together, they select the workorders to be scheduled for
following week. They have until Friday evening to enter the target
date for those workorders into the CMMS. The planners create a
custom table in your
CMMS system into which these records are loaded. You may use
in this table for compliance reporting. (This is a way to "lock" the
schedule since the dates can't be changed in the custom table).
- While designing the KPI and setting up the (% deviation allowable) be sure that
the average exception is in the range of 30-40% and not more. Otherwise,
nobody may be intrested in the KPI. Once the lower deviation is
achieved lower the deviation level to next level. Also make sure that you are not over-maintaing the plant equipment.
- If your planners can't handle incorporating
additional work less than 12, 24 or 36 hours before a shift, that
should be the cutoff time. It should
also depend on how much is already scheduled for that particular
shift, in other words you can't really come up with "one rule fits
all". Additionally, it's recommend that people perform proper RCM
(reliability-centered maintenance) analyses on their plant, so
they know exactly what needs to be done and how often.
It is also recommended that people respond to asset performance deterioration as soon as possible. If not, you get substandard production in either
quantity or quality. If you address deterioration, you should only
few, perhaps random, failures. That means that the overwhelming
majority of your work is planned. So, why should anybody come up
additional work 10 or 12 hours before a new shift? Perhaps the
only reason that your organization responds is to breakdowns. So
may be a reason to
look into how to improve asset management, rather than
worrying whether a cut-off time should be 20 or 16 hours before
- Try not to completely follow another company or organization's example. Determine
what is possible at your company. If your planners can't handle
incorporating additional work less than 12, 24 or 36 hours before
a shift, then that should be the cutoff time. It should also depend on how much is
already scheduled for that particular shift. In other words, you
can't really come up with "one size fits all" strategy.
One industrial manager for a major petroleum
company noted that she always recommends that people perform
proper RCM (reliability-centered maintenance) analyses on their
plant, so they know exactly what needs to be done and at which
frequency. She also recommends that people respond to asset-performance
deterioration ASAP. If not, she noted, you get substandard production
in either quantity or quality. If you address deterioration,
you should only get very few, perhaps random, failures. This
means that the overwhelming majority of your work is planned.
So, why should anybody come up with any additional work 10, or
12 hours before a new shift? She adds that the only reason that
some organizations respond to breakdowns. Hence this is perhaps
a justified reason to look into how to improve asset management,
rather than worrying whether a cut-off time should be 20 or 16
hours before a shift.
What percentage corrective and predictive maintenance
should a company strive for?
Answers or Advice:
- Some feel KPI's and benchmarks may not be such a good idea, as people think
that they should achieve certain published figures (percentages,
A certain Asian factory with several plastic molding
machines rarely used all of them (the machines) at once.
If one failed, they took
the mold and placed it on another, then repaired the
failed machine. This factory doesn't seem to need any preventive
nor predictive maintenance. Imagine if they were going to
strive for 50% condition-based, 45% time-based and 5% breakdown.
Would that save them money?
So beware of KPIs that somebody
else may have achieved. Don't believe that trying to copy
those will guarantee that you will be better off.
alternative would be to calculate the overall equipment effectiveness factor, which is based
on six major losses that all directly affect your profit.
Measure where you are, then analyze which loss contribute
mosts, do something about it and keep improving. Benchmark
first against yourself and be guided by what measuring those
losses tell you. Eventually you may try and compare against
your competitors, but we doubt whether you could get hold
of their figures. Your competitors are the ones to worry
about, not published figures from one particular plant in
Taiwan or Ireland, making something totally different
to what you do.
- The maintenance plan does not stop -- it's a program of activities
that constantly needs to be updated and managed.
are not going to ignore
a critical, unexpected failure just because it's not on the plan. It is all
about risk, and jobs are prioritized and get done
based on the consequences
of the issue to be addressed. If the job has to be
done, put it on the due
list and manage it from there to allow proper assessment
of resources and impact.
Some things to look
1. Align you resources (per trade), to your current
workload scenario with
some safety margin. This implies that you must acknowledge
any current trend
in re-active workload and allow time for this on top
of your pro-active workload
otherwise you pro-active effort is going to suffer.
If the reactive
work does not manifest, you have your backlog then
to help make up your
utilization of resources.
2. Establish risk-evaluation rules on due and overdue
inspection and service intervals are associated with
specific PF Intervals,
a weekly going overdue by one week, is far more critical
than a bi-monthly
becoming overdue in three weeks when evaluating the
principals. You should have specific overdue-management
rules to prevent the
creation of failures.
3. Structure your tasks types to allow a very clear
proactive and reactive work. Proactive work here meaning
that the work is
executed through standard tasks from your CMMS, which
were established as
part of an evaluation process where they were found
to be technically
feasible, safe and environmentally friendly, and cost-effective.
typically your Condition-based Maintenance Task sets
(Scheduled Condition-Monitoring Task and Dormant
Follow-up Corrective Task), Usage-Based
Maintenance Tasks, and Run-to-Failure Task sets (Scheduled-Failure
Task and Dormant Follow-up Corrective Task).
4. Structure you Work-In-Progress/Due- and Overdue-Work
Lists to effectively support planning on resources,
presenting the impact
of the individual tasks
on production availability, spares issues, trade allocation,
criticality, overdue period etc.
The percentage of work done (based on number of, hours,
costs), through standard
tasks as opposed to newly created work orders, is
a good measure of the
maturity of maintenance programs. It is often more
usable than other ratios
due to the huge margin of interpretation and poorly
structured task types
which does not allow effective analysis. For most
industrial companies, if
this percentage is less than 50%, you are very reactive,
above 60%, it starting to
look up and the upward trend should be the target.
It is quite an
interesting discussion about whether 100% is achievable.
Theoretically it's .
There is no short answer