How to Improve OEE – Any Questions?

Ask any Quality or Engineering manager and they will tell you that measurement systems are valuable tools to identify problems and opportunities.  The measurement system itself is not the answer – it is the data source, the EVIDENCE that drives the questions.  It is a part of the discovery and validation process to confirm the opportunity or problem and the effectiveness of the solutions to resolve it.

A well integrated OEE system should provide the data to answer the questions on everyone’s mind, “What do we need to do to improve?” or “Why aren’t we improving?”  The simple answer is, “We need to fix it.”  Of course the real question may not be, “What do we need to fix?” but, “Why did it break?”

Yes, we will likely have to replace the part(s) that failed to get the line back up and running, but what really caused the failure to occur?  What was the real root cause?  This introductory post to problem solving and root cause analysis will kick start some of the techniques used to solve problems effectively.

The Problem Statement:

The key to effective problem solving starts with identifying the problem to be solved.  This is typically a brief statement describing the problem.  For external concerns, the problem is usually stated in customer terms.

This post presents some simple examples of problems to be solved.  You will quickly discover that defining the problem may not be as simple as it looks.  We will discuss this in more depth in our future posts.

Root Cause Analysis

Identifying the real root cause(s) for the failure is the secret to successful problem solving.  The method you use to arrive at the root cause should allow you to confirm and validate your solution before taking action.  Here is an important point to remember:

Do not confuse symptoms with root causes.  

For example, you are driving down the road and suddenly find yourself struggling to maintain control of your vehicle.  Your expert driving skills allow you to pull over and stop on the side of the road.  You get out of the car and walk around to discover that you have a flat tire.  The flat tire is a symptom – not the root cause.

As luck would have it, a police officer who just happened to be following you in an unmarked car, notices your sudden erratic driving behavior and charges you with recklessness and careless driving.  Since none of the tires on the police car are flat, the officer presumes the condition of your vehicle is the direct result of your poor driving skills and bad habits after many years on the road.  Another point to remember:

Do not jump to conclusions

You, like many people, would argue that your many years of driving provided you with the experience necessary to avert danger.  The officer quickly recognizes that your many years of experience have caused you to lose perspective of the potential hazards of driving.  The officer advises that your driving record shows no record of any tickets or accidents and clearly suggests that you have had very few “experiences” with the law and minimal exposure to poor road conditions.

The officer proceeds to charge you, the operator, because you simply weren’t paying attention to the conditions and potential hazards of the road.  You are given a ticket to serve as a reminder to pay more attention to the road and to be mindful of your driving habits in the future.  Then to add insult to injury, the officer advises you to fix your tire and drive carefully. 

Unforgiving of the circumstances and since quota’s have to be met, the charges stand and you find yourself on your way to court.  As you sit in your vehicle, stunned that you just got a ticket for getting a flat tire, you are conflicted and fuming because the officer blamed you, your poor driving skills, and your bad habits for driving recklessly down the road!  The following tip will help you remember:

Operator Error is not a Root Cause

Many times, management is too quick to attribute the root cause to operator error.

5 WHY Analysis

One of the best methods for identifying the real root cause is the 5-Why approach.  The concept of asking the question “WHY?” five times is quite simple.  In practice though, you will find it may not be that easy.  Why?  Because the wrong answer will lead you through a continuing series of wrong answers that ultimately lead to the wrong conclusion.

There is always more than one answer – Which one is correct?

Referring back to our example of the flat tire, you now need an argument to absolve yourself of any blame for the incident on the highway.  In court, the judge asks, “How you plead to the charges before you?”  You answer, “Not Guilty your honor.”

  1. Why?  While I was driving down the road, I got a flat tire.
  2. Why?  Because all the air ran out of my tire.
  3. Why?  Because there was a hole in it.
  4. Why?  Because the tire didn’t have anti-puncture technology.
  5. Why?  Because the manufacturer didn’t design it properly.

Were it not for my expert driving skills, this situation could have been much worse.  As it was, using my superior driving skills, I successfully managed to maneuver my vehicle, without incident, to the side of the road, averting what could have been a disastrous crash.  Therefore, I request to be completely absolved of any and all wrongful doing and I am filing a class action suit against the tire manufacturer to cover court costs, lost wages, and damages as well as my emotional stress.

Clearly not satisfied, the judge requests you to take a 10 minute break to rethink your case.  On your return to the courtroom, you are prepared to present the following argument:

  1. Why?  While I was driving down the road, I got a flat tire.
  2. Why?  Because all the air ran out of my tire.
  3. Why?  Because there was a hole in it.
  4. Why?  Because there was a nail on the road.
  5. Why?  Because the government refuses to keep the highways clean.

Were it not for my expert driving skills, this situation could have been much worse.  As it was, using my superior driving skills, I successfully managed to maneuver my vehicle, without incident, to the side of the road, averting what could have been a disastrous crash.  Therefore, I am filing a class action suit against the government to cover for court costs, lost wages, and damages as well as my emotional stress.  To resolve this matter quickly, I request that all charges be dropped and I in turn will drop my counter-claim.

The purpose of the above example was to demonstrate how the answer to the question – WHY? – can lead to completely different conclusions.  On one hand we’re ready to sue the tire manufacturer and on the other, we’re ready to take on the government.  If there was indeed a nail on the road, how did it get there?

Don’t Assign Blame

Solving problems and getting to the root cause is not about assigning blame to someone or something.  You can’t blame the government or the tire company for the fact that there was a nail on the road.  It is to easy to assign blame and it happens everywhere, everyday.  Perhaps the nail manufacturer should be sued as well for failing to provide adequate protections should the nail become lost or misplaced.

The question that wasn’t asked is, “Why was the nail on the road?”  The answer may be that it likely fell out of a board or from a truck or trailer that may have been carrying construction materials.  Again, being careful with the answer, we don’t want to come to the conclusion that nails should be banned completely.

On the other hand, it may be worthwhile to advise that all companies and contractors must make a reasonable effort and take appropriate precautions and measures to ensure that all loads are secure and free from loose raw materials.  Any nails must be placed in a sealed container and secured to the vehicle for the purpose of transport.  A maximum fine of $2,000.00 may be imposed and made payable to the “Operator Error Trust Fund.”

Leading the Witness:  The solution BIAS

STOP! – if you think you already know the answer – Stop!  We know that the right question doesn’t always lead to the right answer as we attempted to show in our example.  Another major pitfall is thinking we already have the answer and we just need to frame the questions and answers to support that conclusion.  This isn’t problem solving, this is creative story telling.  Don’t lead your team into following what “appears” to be a logical conclusion – be prepared to prove it.

Don’t Assume Anything – Follow the EVIDENCE

At a minimum, follow the evidence.  What is the data telling you?  It’s time to start thinking like a crime scene investigator (CSI) or good lawyer.  Asking questions and continuing to probe for answers is the secret to uncovering the less obvious and, more than likely, real solution.

Many OEE equipment / software integrators provide the ability to record and track downtime events in real time.  This data is extremely valuable for trouble shooting and problem solving; however, they are not necessarily root causes.  The integrators provide the capability to readily identify what part of the process failed or what is broken.  While this may be the cause of the line down condition, it is not the root cause of the problem.

Do not confuse the Point of Failure (Source) with the Root Cause

Don’t fall into this trap:

  • Supervisor:  “The OEE system report showed that we lost two hours on the paint line last night.”
  • Maintenance:  “Yeah, I saw the report too.  This OEE system tracks everything!”
  • Supervisor:  “Why did the line go down?”
  • Maintenance:  “The A-Tank feed pump overheated.  The OEE system told us exactly which pump failed.  It saved us a ton of time.”
  • Supervisor:  “What did you do?”
  • Maintenance:  “Oh, we replaced it.  The line is running fine now.”
  • Supervisor:  “OK, that’s good.  Thanks.”

End of conversation.

So, WHY did the pump overheat?  Some questions just never get asked, but I’m sure the OEE will be just fine on the next shift.  We recognize that most effective TPM managers are sharper than this.  Our point is that not everyone is looking at the data from the same perspective.

We’ll discuss “How to Improve OEE” in more detail in our next post:  “How to use the 5 Why Approach.”

Until Next Time – STAY lean!

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