|
Issue No. 32 - December 2009 |
|
Since establishing this website last May of 2007, I have made many efforts to improve this site and provide some useful insights about our common link which is all about improving our equipment reliability and the way we do maintenance.
Finally should you be interested to contribute to our articles section or share any feedback, I encourage you to email me Click here to email me. If for any reason you wish to unsubscribe from our newsletter, kindly send my a blank email with unsubscribe as the heading and we shall remove you from our mailing lists. Once again welcome to our December 2009 Edition of our Monthly Reliability Newsletter for this year 2009 and I hope that you enjoy reading and sharing with your people.
My Warm Regards,
Website : www.rsareliaiblity.com Inspired by Change . . . |
|
RELIABILITY & MAINTENANCE CONSULTANCY FIRM
|
|
Where the learning just never stops . . .
|
|
RSA
|
|
For our complete archive of previous reliability newsletter |
|
RSA Reliability and Maintenance Consultancy Firm values the privacy of your email. Should you wish to unsubscribe or do not want to receive any more email or messages from us kindly send me a blank email with unsubscribe on the subject and we will remove you from our mailing lists. Click here to Unsubscribe ! |
|
You are receiving this newsletter and email because at some point in time you opted to be included in our Monthly Reliability Newsletter mailing list from our site.
Our newsletter will be sent out ones a month and provide you with quality issues and resources on our most common link which is all about reliability and maintenance, as well as regular updates about our site. I would like to personally invite you to regularly visit our website and check out updates on our articles and training courses. |
|
The traditional belief leaves maintenance people to think that all parts have a life and that replacing or overhauling these parts before they fail on a specific period will eventually restore the parts back to their original condition. If you say that this is right, then you are so wrong! This thinking is the reason why most Preventive Maintenance activities result to being reactive itself. |
|
By Rolly Angeles
In a typical plant or industry, the equipment is scheduled on a time-dominated or calendar based pattern with a lists of activities to comply. Some of these activities will include the following :
• Cleaning and lubrication • Replacement of parts • Overhauling and scheduled restorations • Routine and Functionality inspections • Performing rebuild and repairs
|
|
Problem Number 1 : Not All Parts Will Eventually Wear Out
The problem begins when most people who perform PM assumes that the condition of the machine is deteriorating and that the need to perform maintenance is correlated with the passage of time or age which means that the item can be expected to operate reliably for an amount of time and is expected to eventually wear out with respect to its operating age. This is true if the part, spare or component to be overhauled or replaced have a clear wear-out or age-related pattern and the part is said to survive this specific age.
The truth behind all of this is that not all parts of your equipment will eventually wear-out. Others will fail randomly, while others will fail prematurely right after an extensive PM overhaul or replacement is done. Let me put it this way, if you are driving your car and a rock hit your windshield that created a small fracture, the question to raise is when will the second rock hit your windshield. Nobody knows. Preventive Maintenance cannot tell. This is what random failures is all about. They can happen anytime. A different type of maintenance tasks or strategy is needed but not PM. This means that if the failure you are experiencing in some of the parts of your equipment is random, then this is where Preventive Maintenance will be useless and ineffective. If most of the failures you experience are from electronic boards, then the best thing to do is either duplicate the PCB that fails frequently or perform a thorough Root Cause Failure Analysis Investigation to get to the bottom of the problem. Do not overdo or overuse the use of Preventive Maintenance. Performing intrusive or forced maintenance on an asset will just do you more harm than good.
One of the most important discovery in the field of reliability and maintenance that all maintenance people should know and understand is that in the real world, there actually exists 6 patterns of failure. The 6 failure patterns will provide us an indebt understanding on how certain parts in your equipment behave and as well as fail. If you have no idea what the 6 failure patterns are, you might want to click on this link and read my previous newsletter. The 6 failure patterns was discovered by Stanley Nowlan and Howard Heap of United Airlines way back 50 years ago in their attempt to improve the reliability of commercial aircraft by improving the way they do their maintenance. Their discovery “SHOCKED” the maintenance function because only 14% of failures can be prevented by performing Preventive Maintenance, while 86% of equipment failures cannot be Prevented by doing any form of Preventive Maintenance.
RSA Reliability Newsletter Feb. 2008: An Inconvenient Truth About Preventive Maintenance
Problem Number 2 : Similar Machines Will Not Require The Same Degree of Maintenance Requirements
Another problem with performing Preventive Maintenance is that people who plan and perform their PM activities will assume that similar equipment will have the same amount of maintenance requirements irregardless of how the equipment is being operated. This is not true. The only time that the activities will remain the same for similar types of equipment is that if both equipment are operating on the same conditions. If I have a pump and the pump is discharging water, I cannot perform the same amount of maintenance to a similar pump which is pumping out acid or slurry. The impeller in this case will erode much faster compared to the other pump which is pumping water. Likewise for manufacturing plants, you simply cannot perform the same degree of maintenance requirements for a machine which is running 24 hours a day for 7 weeks against a machine that is only running 1 shift for 5 consecutive days.
Another case which I can share is that if a team performs an improvement or modification on a piece of equipment, there is a temptation of replicating this improvement/modification on similar machines. Their presumption is that they do not want the problem to exists in other machines. This is valid if the other machines that will be replicated suffer the same problem as the original machine which the modification or improvement had been generated. But if some machine similar in nature simply emits no form of problem and is considered stable, might as well leave that equipment alone. Don’t replicate the improvement in this machine. There is a probability of inducing new problems on that piece of equipment.
Problem Number 3: Introduction of Infant Mortality Failures
Infant Mortality Failures are failures which actually occurs during the beginning of life. You might have experience this where operators have a hard time starting the equipment most especially when the equipment is newly commissioned, overhauled or right after performing a shutdown or outage. Others might refer this as starting-up failures, debugging or commissioning failures. When operators complain to us maintenance that they find it difficult to run the machine, then you have been a victim of Infant Mortality Failure. Many factors can induce infant mortality failure such as lapse or slip on the maintenance to put the equipment back together in one piece and on the same condition as it was before. Human errors can occur in dismantling and putting the equipment back together only to realize that a small spring/bolt/nut or other piece was not placed back in the equipment and again it will take us a couple of hours or more just to correct these kind of things. Most of us just pretend that no one saw that and just keep this small part away in the PM bay. Or perhaps you have dismantled some stable systems inside your equipment that should have been left alone |
|
The lists of activities performed varies from one type of industry to another and depends upon the type of equipment being maintained. By definition Preventive Maintenance (PM for short) is also a series of tasks performed at a defined frequency dictated by the passage of time either in the amount of machine hours, mileage or running hours that either extend the life of the asset or detect that an asset had a critical wear and is about to fail or break in operation. PM is also a basic maintenance performed on the equipment and facilities in which the main goal of performing the task on a scheduled basis is to extend the equipment life and to assure its capacity in supporting the industry’s goals and targets. The thing to consider in doing Preventive Maintenance is that the cost of doing PM should be less than the cost of failure it is meant to prevent. This means that if the cost of performing Preventive Maintenance is 1000 USD and the costs of failure it is mean to prevent is 200 USD then performing PM is not feasible to use. The intentions of performing PM is without a doubt very noble but most industries simply cannot maximized the benefits derived in performing their PM, let us explain some of the reasons behind it. |
|
If your operator encounters a lot of problems in getting the machine to run smoothly then it is a good thing to revisit how you perform your Preventive Maintenance on that piece of equipment. Infant Mortality failures exists and the most likely cause is overdoing your maintenance on the equipment. That is the reason for the title of this newsletter that more PM will just result you to more problems.
I remember one time when I arrived at India airport in Mumbai around 11:30 pm, it will take you around 30 minutes to clear the immigration and to get your luggage. At the exit point a driver holding my name was waiting for me and we went straight to the hotel. When I finished checking in at my hotel, I went straight to my room, change my clothes place the “Do Not Disturb” sign and went to sleep. After a few minutes someone was knocking and I opened the door. The guy dressed in their hotel uniform greeted me with a smile and said, how was your day ? How is your room ? Do you feel comfortable ? Do you know how to use the buttons near the bed and all that sort of stuff ? After that finally he said, was there anything else you need ? I told him yes there is, I hope you can read this sign “Do Not Disturb” and shut the door. I admit I was a bit rude, but kindly understand that 11:30 pm was when the plane finally touchdown the airport. I arrived at the hotel around 1:00 am which is actually 3:30 am in my country. There is a difference of 2.5 hours from my country to this country. How would you feel?
Your equipment is like a hotel. Inside the hotel are many rooms. If someone is staying in the room you have the option to place either a “Do Not Disturb” or “Make My Room” sign. If you place a do not disturb sign only to be disturbed then you get pissed off. But on the other hand if you place a Make My Room sign on the door, then expect someone to knock on your door to clean your room. My message here is very simple, if you have all the tools, knowledge and skill to dismantle and bring the equipment back in one piece then go ahead and overhaul it for all I care. But if you have the slightest doubt to bring it together in one piece, then you might as well think again about dismantling or overhauling your equipment. I think the less we overhaul then the less the equipment will fail and induce what we call “Infant Mortality failures”.
One of the best example I can provide the readers is studies done by Stanley Nowlan and Howard Heap on civil aircraft showed results that 68% of items that failed conformed to pattern F which is the case of Infant Mortality Failures. An example of some of the benefits achieved from this learning on infant mortality failures by the civil aircraft industry was based on a dramatic reduction in their scheduled overhauls in their DC-8 aircraft from 339 items for overhaul to only 7 items in their DC-10. DC-8 is a much smaller aircraft compared to a DC-10. But in DC-10, they have dramatically reduced the amount of overhauls done on this more bigger and complex aircraft. One of the items no longer subject to overhaul was their turbine engines. Likewise on the initial program developed for Boeing 747, it took United Airlines 66,000 man hours on major structural inspections to reach an inspection interval of 20,000 hrs compared to their traditional 4 million man hours inspection on smaller and less complex aircraft such as DC-8. Today, it is simply much safer to ride aircraft today than it was 40 or 50 years ago, because the rate of accidents per million take-offs during those times was around 40 to 60 which means that for every 1 million planes that take-off. Around 40 to 60 planes will go down. Was it magic, no of course, it is just about learning the lessons on infant mortality failures.
To conclude this Reliability and Maintenance Newsletter for this month, in adopting any maintenance strategy on how to maintain our equipment, the strategy must always be 3 folds. Maintenance activities and tasks that will address Infant Mortality Failures, those that will address Random Failures and those that will address Wear-out or Age-Related Failures. Preventive Maintenance is only design to capture age-related failures which is roughly around 20% of the equipment failures we experience and that leaves us 80% of equipment related failures that needs to be addressed as well. And I think that is all I have to say about that.
Other RSA Newsletter References on this Article :
RSA Reliability Newsletter Feb. 2008: An Inconvenient Truth About Preventive Maintenance RSA Reliability Newsletter May 2008: Top 10 Problems Experience on PM RSA Reliability Newsletter Aug. 2008: The Case of Infant Mortality and Random Failures
|
RELIABILITY NEWSLETTER |
|
RSA |
|
Inspired by change |
|
• Gallery: New pictures for 2011 added from the gallery portion. • Newsletter: Aug. 2011 Edition finally released to our subscribers. Email me if you want to subscribe to our Newsletter. • 2012 Training Schedule: If you are interested to attend in any of our public workshop and master class for 2012. Send us an email or register online. • WCM Book: If you’re interested in buying the book on World Class Maintenance, The 12 Disciplines. Send me an email to reserve. WCM Book is now available. Get your copy now. • In-house Training :Should your industry be interested for in-house trainings we are now accepting regular schedules for in-house training for both local and international countries on courses that we currently offered. Contact us |
|
World Class Maintenance Management - The Twelve Disciplines Book is now available here. This is not only about the technical jargon on reliability and maintenance, it is a book that makes every single maintenance proud that they belong to the maintenance function. If you have been living through the day to day pressures of doing maintenance then this is your story. If you are interested in this book, send me an email. Click Here ! |
|
Select the courses of your choice and it can be made available in CD . Click Here ! |
|
We are very much flattered and humbled by your feedback and testimonies. Your messages are the main reason for allowing us to stay in this business. With all humility we say thank you and rest assure that we are continuously improving. Without your support in our training there won’t be us. Read More ! |
|
• Registration at this forum is done through administration only. Should you be interested to join send me an email and we will provide you with a user ID and password. Visit my discussion board and forum . .
• Share what you know. Come and join our RSA Maintenance Forum. Send me an email |
|
• If your industry is interested to join and participate in any of our upcoming public training and workshop for this year 2012 you may send us an email or simply fill out the registration form provided on our schedule site. You may Click here to visit our schedule training for 2012 Schedule. |
|
Our Reliability Newsletter will be provided once a month to our valued subscribers. It provides highlights as well as issues and lessons regarding our most common link which is all about improving the reliability of equipment. |
