Torbjörn Idhammar
VP and Partner,IDCON, Inc., a maintenance management
consulting and training company.
Further information is available by contacting info@idcon.com
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High investment costs mean that it is the interests
of paper makers to look after their equipment. After all, prevention is
better than cure
In today’s highly competitive market, mills cannot afford to be
let down by their machines, so maintenance procedures are a crucial element
in any company’s performance strategy. In a bid to improve reliability
and performance, mills can chose one of two ways to carry out their maintenance
tasks, both of which lead to higher production throughput and lower costs.
Using the first approach, mills can invest in maintenance prevention.
Under this system, it is essential that companies specify and buy the
right equipment. Added to that, attention needs to be paid to basic operations
such as lubrication, alignment, balancing, proper storage of components,
filtration and detailed cleaning. Where possible, mills should also look
into using a Fixed Time Maintenance (FTM) program. And, last but not least,
it is crucial that mills follow proper operating practices.
The second way in which mills can improve their maintenance performance
is to carry out the remaining maintenance work in an efficient manner.
This can only be achieved with adequate planning and scheduling, which
involves leaving enough time between identifying and carrying out the
work. Prioritizing requests and condition monitoring must be standard
practices at mills that go for this approach.
Clearly, there is nothing new or revolutionary about these two methods,
but in most organizations the improvement potential of these processes
is huge. Mills often overlook the opportunities on offer, but improvements
can easily be achieved if companies go back to implementing the very basics
of maintenance. Few investments in maintenance improvements pay off faster
than the implementation of new or revised cost-effective preventive maintenance
procedures.
The Idcon maintenance consultancy recently worked with two pulp and paper
mills to carry out basic preventive maintenance inspections. Experience
showed that the secret to getting the most out of a company’s money
lies in improving the very basics of operating and maintenance procedures.
Following the work at the two mills, cost savings at both plants totaled
more than $1 million in little more than six months and 12 months, respectively.
Figure 1 shows where the savings were achieved and which method was used
to detect potential problems. It is clear that almost all of the reports
were a result of look, listen, smell and feel type inspections.
It may come as a surprise that vibration analysis (VA) accounted for just
7% of all problems identified, but this particular mill had been running
an excellent VA program for close to 10 years. Even so, the VA program
had failed to identify problems such as worn out V-belts, sheaves, sprockets,
chains, coupling elements, coolers close to failing and internal hydraulic
leaks.
Shedding light
It is also revealing to see what a difference can be made if high intensity
light is used for inspections. Before this method was used, employees
used only regular flashlights. When they started using lamps with one
million candlepower light intensity, a new world opened up and problems
that could not be seen with a normal flashlight were identified. Meanwhile,
many of the problems detected with the infrared (IR) thermometers used
related to mis-aligned couplings. Most of these couplings would later
have been detected with VA, but the IR method is faster and simpler and
it also generated a heightened interest among operators to carry out inspections.
figure 2- The implementation cost and the results achieve
in one mill over 12 months
In both mills, the results highlighted the importance of training operators
and tradesmen to carry out inspections. Most tradesmen are good at repair
work as the majority of training programs are focused on fixing components.
By contrast, very little training focuses on how to carry out basic inspections.
For example, without training, the inspection of a cooler would simply
involve checking for leaks and whether the cooled media is at the right
temperature. After receiving training though, operators would note the
position of the bypass valve or water inlet valve. If a water inlet valve
is almost fully open in the month of May, it is easy to understand what
will happen in June, July or perhaps November if the mill is in Australia.
The key to a successful preventive maintenance system comes down to paying
attention to detail. The people involved in maintenance prevention and
condition monitoring must be trained to become detectives of possible
failures, not just observers that casually pass by the equipment. For
example, one person may note that an electrical motor is hot and then
report the problem to an electrician so that he/she can check out the
problem. In contrast, a detective would scan the motor and note the location
of the hotspots. A detective always continues to ask why a problem is
occurring.
Figure 3- Using an infrared gun, operators can discover
why a motor is overheating
If we take one typical example (Figure 3), the detective in this case
may wonder why the shaft side of the motor is hotter than the middle of
the motor. From the data, it is clear that the motor needs to be cleaned,
but it is still unusual that the shaft side is hotter than the middle
of the motor. After cleaning the motor and checking its load, it became
obvious that the front bearing was the heat source. The outstanding question
was why.
The detective has two main hypothesizes for the cause of the failure -
lubrication or misalignment. Taking the temperature of the coupling and
the shaft side pump bearing clarifies that misalignment was the actual
cause of the failure. After further inspection, it was noted that the
foundation was poor and the base had corroded. In other words, the foundation
was at the root of the misalignment problem and this made it impossible
to realign the motor to specification.
The corrective work in this case was extensive because there were a variety
of failures associated with the problem that were not detected in time.
The mill in question had just started its preventive maintenance process
and it became obvious that there were many faulty bases and foundations
onsite. A preventive maintenance process helped this mill to focus on
the very basics that made its operations run.
On the record
At both of the mills that Idcon worked with, all inspections were documented
in an inspection system and those carried out by operators or tradesmen
were given the highest priority. A key to success is that inspection results
are acted upon so that a problem only needs to be reported once. In addition
to savings in increased reliability as well as lower maintenance and operating
costs, it is also very common to see a reduction in the total hours and
material spent on preventive maintenance. If carried out correctly, the
vast majority of inspections can be made while the equipment is in operation.
Another cost saving opportunity that mills can take advantage of is to
have all its preventive maintenance activities documented in the same
system. This makes it possible to see all the activities per equipment
piece in one document, eliminating unnecessary duplications of preventive
maintenance work.
As paper companies increasingly look at ways to cut costs and run more
efficient operations, it is worth bearing in mind that forewarned is forearmed.
Or to put it more plainly, it is 5-20 times more expensive to react to
a problem then to prevent it.
Consider IDCON’s Preventive
Maintenance Manual and/or our Condition
Monitoring Standards
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