May - Library

p roblems, and getting their ideas on how we can improve the design’.
Certainly these are important, but not likely to be sufficient. Let’s ask
the following:
A.In light of the failure modes analysis described above, how will
you modify the design of your equipment to eliminate, mitigate or
better manage (through condition monitoring methods that allow
early detection of problems) these failure modes? If condition
monitoring technologies or methods are applied, please describe
those that apply, including their potential costs and benefits.
Include in your discussion a review of the application of
continuous monitoring.
B.Describe 3 or 4 design changes that have been made as a result
of working with your customers, and why. What additional
efforts are currently on-going for improved reliability and
maintainability in the equipment?
C.Attached is a listing of several problems that we have had in
reliability and maintainability. Please provide us with a
description as to how you will address and resolve these
problems in the design to assure improved reliability and
maintainability.
D.Will approval of your drawings be permitted, and if so, in
sufficient time to allow for equipment modifications and still
meet the project schedule? Please outline your plans.
Experience with Reliability and
Maintainability
When asked about their specific experience in providing reliable,
readily maintainable equipment, or more to the point, when asked
about the reliability of the equipment being procured, a typical reply
f rom the supplier might be ‘This equipment has been installed in many
places throughout the world, and has operated very re l i a b l y. In
particular, this equipment was installed at the First-Up plant, and had
few difficulties during commissioning, and is currently running re l i a b l y.
I t ’s also been installed at the Next-Other plant. Let’s ask the following:
At the First-Up and Next-Other plants, please respond to the
following for each plant:
A.What has been the historical average % unplanned maintenance
downtime?
B.What is the mean time between repair?
C. What is the mean time to repair?
D.What are the five most common failure modes?
E.What is being done in the design to mitigate or eliminate these
reliability and maintainability issues?
F. How long did the commissioning process take to achieve full,
sustainable production rates? How many failures and of what
duration occurred during that period? Did any supplied parts
exceed the guaranteed failure rate?
G.What were the major problems encountered during
commissioning?
H.What design changes have been made to minimize these
commissioning problems?
I. What is the standard commissioning process? We desire that
the equipment run at least one full production cycle while
maintaining full production requirements. We also desire that
this same test be repeatable within 6 months of initial
commissioning. Please describe your process for meeting these
requirements.
J . We desire a mean time between failure (MTBF) of not less than
_____ hours. For our purpose, a failure is defined as anything that
occurs with the equipment that results in any downtime,
p roduction rate reduction, or quality loss. For example, at a ____%
confidence level, this re q u i res that we have no more than ____
f a i l u res during a ____hour period. Please aff i rm your commitment
to running a commissioning test over the period stated with these
specific confidence limits, and pre d e t e rmined number of failure s ,
or offer your alternative that will meet this need.
Developing Suppliers That Provide Reliability and Maintainability
K.Could you arrange for our engineers and purchasing people to
visit these two plants, and perhaps other plants, to review their
practices and performance?
PM and Spares Requirements
When asked about PM and spares re q u i rements, and how they are
developed, vendor responses vary considerably. A typical answer
might be ‘Spares recommendations are based on our experience and
on feedback from our customers, separated into capital spares and
routine wear parts, with expected lifetimes.’ What this means is not
very clear. To add greater clarity, let’s ask the following:
A.What statistical methods and other techniques were used to
convert your experience and feedback into spares
recommendations and PM intervals? In light of the failure
modes described above, and assuming the failure modes cannot
be entirely eliminated in the design, describe how these PM will
assure mitigation and/or early detection of these failure modes.
Describe how the spares recommended are to be used for better
managing these failure modes.
B.Please provide one example of each major component analysis,
wherein techniques such as RCM, FMEA, PM Optimization were
used in conjunction with statistical failure and wear data to
determine PM requirements and intervals and spare parts
requirements.
Training
Training is critical for the proper startup, operation and
maintenance of new equipment. A typical question might be ‘What
level of training is re q u i red for operators and maintainers for
equipment of this type?’ A typical answer might be ‘We do good
training, and much of the equipment is automated, minimizing the need
for training.’
Increased automation is more likely to increase the complexity of
the equipment, resulting in a need for greater skill and competency in
our staff, not less, particularly during problem analysis and corre c t i v e
action. With this in mind:
A.Describe the operator training, as well as mechanical and
electrical maintenance training required to assure world-class
practice, including a detailed outline of all training and support
requirements that will be necessary for supporting the reliable
operation and maintenance of the equipment.
Summary
Using the model outlined above should be an integral part of an
overall strategy for minimizing the total cost of ownership for major
capital equipment. The key to using this approach is having a good
understanding of your current operating results and problem are a s ,
the failure modes most likely to result in lost production, downtime, or
high costs; or that may have the most severe consequence to your
overall operation. Having a good understanding of these issues will
a s s u re that you can work with your supplier to eliminate, mitigate, and
manage these risks; and that you can minimize your total cost of
ownership, and be more profitable. Many of you may be far along the
path for this and have more detailed processes to achieve the above
re q u i rements. No doubt others would consider these re q u i re m e n t s
beyond the scope of many of your procurement efforts. Somewhere
in the middle are many of you who could use this model to more fully
develop your re q u i rements for improving reliability and maintainability.
Hopefully the suggestions above will help you in that effort.
Ron Moore is Managing Partner of The RM Group, Inc., Knoxville,
TN, and author of Making Common Sense Common Practice: Models
for Manufacturing Excellence from Butterworth-Heinemann. He can
be contacted by telephone at 865-675-7647; or by email at
RonsRMGp@aol.com.
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