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(+)+(+) S.M.I.L.E(sm)
(+)+(+)
(+)+(+) Setup Minimization Improves Line Efficiency
(+)+(+)
(+)+(+) The Lean Changeover e-letter
(+)+(+)
(+)+(+) Published monthly by Changeover.com
(+)+(+)
(+)+(+) Written by John R Henry, CPP
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SOME THOUGHTS ON...
EFFECTIVE TROUBLESHOOTING


One of my popular in-plant workshops is “Effective Troubleshooting”. It teaches mechanics, technicians, engineers and others the basics of troubleshooting mechanical, electrical, control and other systems. This month I will share some of the highI thought that this month I would share some of the high points.

Let’s begin with a couple of definitions:

“Troubleshooting is the art of determining the cause of a problem in a system.”

“Effective troubleshooting is the art of doing it effectively.”

Anyone with any experience at it will agree that finding the problem in a system and the cause(s) is often harder and more time consuming that actually fixing it. An aggravating factor can be that there is no methodology used in the troubleshooting. The technician simply tries one thing after another until the system works again. Not only does this waste a lot of time, it can lead to aggravating rather than ameliorating the problem.

Here is the methodology I recommend and use:

Prior to beginning, understand how the system is supposed to. Some of this will come from some from general experience and training, some from specific training on the system, some from observation. If the technician does not understand how the system is supposed to work and the internal functions that cause it to work, it is unlikely that they will be able to get it to work. Or, if they do, it will be by random accident.

Most systems have visible as well as invisible functions. A labeler may dispense the label onto a tamp pad then apply it to the product with an air cylinder. The dispensing (via motor drive) and application are visible and easy to understand. There is also a complex series of timings that make sure that all these steps (and more) happen in the appropriate sequence and time. If the timing logic is not understood, it will be difficult or impossible to properly diagnose problems much less resolve them.

Once the system is understood the actual troubleshooting can start. I use a 5 step system. I will use the singular here for clarity. Bear in mind that there may well be more than one problem and more than one cause of the problem.

Step 1-Identify the problem

If you do not know what the problem is, it will be impossible to fix it. This is different from determining the cause of the problem. The operator may call and say “The capper is not working right.” That may say that there is a problem but does not give the first clue as to what the problem is. Is it starting and stopping? Running jerkily? Failing to apply caps? Failing to properly torque the caps?

This is an area where operator training can be very helpful. The more they can know about how the machine is supposed to work, the more information they can give describing the problem. Additionally, the better they know the machine, the more ability they will have to advise of a problem, or even a potential problem, before it becomes a catastrophic failure.

Step 2-Identify the root cause

The root cause may not be the same as the apparent cause of the problem. Toyota uses a technique (adopted from Henry Ford) called “The 5 Why’s” to get to the root cause. This technique uses a series of questions, each building on the previous answer, to find the true, underlying or “Root” cause of the problem.

An example:

Ask “why” 5 times:
(1) Why did Sarah slip and fall? Because there was oil on the floor.

(2) Why was there oil on the floor? Because the machine had a leaking shaft seal.

(3) Why was the shaft seal leaking? Because the shaft was damaged.

(4) Why was the shaft damaged? Because of improper tool usage.

(5) Why was an improper tool used? Because the proper tool was not available.


There are intermediate solutions at each of these steps that must be implemented. The oil must be cleaned up, the seal replaced and the shaft repaired. None of these is a final solution. If the root cause, improper tool usage, is not corrected the problem will recur and likely even get worse.

Step 3-Identify and choose the best solution

A key here is to realize that there is usually more than one dimension to “Best”. It may be the cheapest, it may be the fastest to implement, it may be one that is within the organization’s capabilities. It may also be a replacement and restoration to previous condition or it may include an upgrading. All these possible dimensions need to be considered.

The solution may also be temporary. If a machine used in production starts overheating, a temporary solution may be to direct a cooling fan on it until the end of the day rather than interrupt production. This may be fine, provided that when production stops the cause of the overheating is identified and corrected. It is probably not fine if 6 months or a year later the fan is still there.

Step 4-Implement the solutiion

Once the solution has been identified, it must be implemented. ‘Nuff said.

“A solution without implementation is nothing more than a good intention”-Peter S. Drucker.

Step 5-Document what was done.

If it is not documented, it did not happen. There needs to be a system log book or file where the problem, cause and resolution can be recorded. This not only makes the process easier the next time there is a problem, it also makes it possible to track trends. If the problem is recurring, it is likely that the true root cause is not being addressed.

The above is a 25 cent description of how to troubleshoot any system, obviously there is much more. If you are interested in having me present my Effective Troubleshooting workshop in your plant I am happy to do so. For a proposal or more information, please contact me johnhenry@... or by phone at 787-550-9650 during eastern US business hours.

TIP OF THE MONTH...
VIBRATION INDICATOR

One tool for monitoring system health is vibration analysis. There are sophisticated systems on the market costing tens of thousands of dollars that will give enough information to choke a large horse. These have been around for some time and are valuable tools. Price and complexity mean that they do not get used that often especially on smaller equipment.

There are currently available vibration meters that will fit in a shirt pocket. The sensor is pressed against a motor and a digital display gives frequency and amplitude. These meters are inexpensive (some less than $700) enough that there is no reason every mechanic or at least every shop should not have one. One source for these and many other good troubleshooting instruments is Reliability Direct at www.reliabilitydirect.com

Best,

John R Henry CPP