World Grain - September 2010 - 84

MILLINGOPERATIONS

nance practices within the facility is a
good starting point. Targeting a goal established by the industry or other facilities within the company is an objective
standard which can measure improvement as well. Areas that are easy targets
to measure and improve include labor
cost (both in-house and contracted),
spare part inventory and planned and
unplanned downtime for the processing
facility.
For example, an easily measured
goal is tracking the number of hours
or occurrences that cause production
interruptions.
Excessive unplanned repairs should
lead to a review of the facility's approach to preventive maintenance. A
sound preventive maintenance program is the foundation for equipment
reliability and directly proportional to
the facility's processing and financial
performance.
DEFINING ROLES
AND RESPONSIBILITIES
Addressing the existing roles and responsibilities of the various departments
in the organization that conduct maintenance activities is vital when reviewing
maintenance practices.
Questions to ask include: Are maintenance tasks conducted by personnel
on multiple shifts? How are responsibilities divided? Do the day-shift
personnel handle maintenance issues
within day-shift hours and which
maintenance personnel are responsible for issues that occur during other
hours? Who has primary responsibility for preventive maintenance tasks?
What maintenance is performed by
other departments such as cleaning
assignments for sifters and roll changing that in many cases are done by the
milling department? Do preventive
maintenance tasks receive the priority
necessary to stay on schedule?
Answering these questions is the
only the beginning in your task of reviewing the effectiveness of how the
preventive maintenance program is
implemented.
86

SCHEDULING AND PLANNING
Effective preventive maintenance
programs begin with scheduling. It is
important to assign sufficient time or
people for the specific task of completing scheduled preventive maintenance.
When reviewing maintenance records,
are there a significant number of work
orders that were not planned? When a
repair is required due to an emergency
or unplanned occurrence, productivity

vibrations in equipment that are not easily noticed. By monitoring equipment
for vibrations, they can be identified and
corrected before the vibrations result in
excessive wear on the equipment.
Monitoring of equipment is vital for
proper scheduling and planning. There
are many ways to monitor periodic maintenance requirements for equipment.
Fixed interval maintenance is required for almost all equipment. The

Subjective inspections are the responsibility of all plant personnel. Subjective inspections are as simple as using one's senses
when walking through the facility.

of everyone suffers. Work orders need to
be well planned and the required materials ready for the mechanics when they
received their assignments. When preventive maintenance receives priority,
unplanned downtime will be reduced.
Tracking of repairs is also important.
Is the same piece of equipment being
repaired often? Are repeated repairs
tracked to be sure the cause of the breakdown is eliminated, or is it simply the
symptom? If a fan bearing is replaced, is
it confirmed the fan is properly balanced
and the belts are properly tensioned? If
a motor burns up, are the fuses checked
or overloaded to see why they failed to
protect the motor?
Predictive maintenance practices are
activities that are performed in order to
find failures early. Regularly scheduled
infrared scanning of electrical circuits
and panels identify hot spots. Hot spots
in motor control circuits are the result
of loose or worn connections. Infrared scanning of these circuits identifies
these potential problems before they result in unplanned downtime.
Vibration analysis of motors and all
rotating equipment help with the early
detection of wear to allow corrective actions to be planned. Vibration is the most
destructive force in any rotating equipment. Wear on bearings, belts, isolation
pads and many other parts can result in

best resource for determining the necessary interval is the manufacturer.
Changing the oil and air filters in positive displacement blowers and tightening the brackets suspending a sifter are
examples of maintenance that should be
performed on a regular fixed interval,
generally based on the number of hours
a piece of equipment is operated.
Objective interval maintenance is
based on monitoring operating conditions of equipment and planning maintenance based on pre-determined targets. One example in grain processing
facilities is the monitoring of magnehelic gauges measuring the pressure drop
across filter socks to determine when to
replace or clean the socks. Another example is the monitoring of amp loads
and product granulation to determine
when to replace worn grinding rolls.
Subjective inspections are the responsibility of all plant personnel. Subjective
inspections are as simple as using one's
senses when walking through the facility. Stop, look, listen, feel and smell. Be
aware of changes in the mill environment that may be caused by equipment
wear.
MONITORING THE SPARES
AND SUPPLY INVENTORY
An evaluation storeroom inventory
can also be a revealing experience and

September 2010 / World Grain / www.World-Grain.com

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World Grain - September 2010

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