Other observations During the CAPA process.

Q

QE

Dear Friends

On my Job as a Quality Engineer, I perform CAPA investigations. Some intresting things I observed in my last year is that every CAPA has several
things which led to the breakdown and eventually cause the failure of a product. in other words there are multiple root causes other than a direct root cause.

My question is, How does the industry experts having CAPA knowledge take care of the side observations which might be presenting an opportunity for improvement ? can some one advise ?
 

qusys

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I think one should fix the root cause to solve the problem.
organization should select the most probable cause , wihtin a set of potential ones,that caused the problem.
There are methods for Problem solving that deal with this kind of process.
 
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howste

Thaumaturge
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If you've identified multiple causes and you've confirmed that each led to the problem, then the corrective action(s) should address them all.

If you have multiple potential causes, but you're not sure which are true causes, select and address the most probable cause.
 

Jim Wynne

Leader
Admin
Dear Friends

On my Job as a Quality Engineer, I perform CAPA investigations. Some intresting things I observed in my last year is that every CAPA has several
things which led to the breakdown and eventually cause the failure of a product. in other words there are multiple root causes other than a direct root cause.

My question is, How does the industry experts having CAPA knowledge take care of the side observations which might be presenting an opportunity for improvement ? can some one advise ?

I don't think I've ever seen a nonconforming condition that had more than one root cause. What you might be seeing is one root cause and one or more potential causes of the same condition. If you can't separate them (if you're not sure which potential cause is the culprit in a particular instance) you need to deal with all of them. If you know (or have good reason to suspect) that some phenomenon has the potential to cause trouble, fix it.
 

howste

Thaumaturge
Trusted Information Resource
I don't think I've ever seen a nonconforming condition that had more than one root cause.
I had a problem several years ago where a USB cable would go into a disk drive, but would lock in place and couldn't be easily removed. After some investigation, we found that both mating parts had problems. If either one of the conditions existed by itself, the parts still functioned properly, but the combination of both conditions caused the problem. In this case, actions were taken on both parts to ensure there would be no recurrence.
 

Jim Wynne

Leader
Admin
I had a problem several years ago where a USB cable would go into a disk drive, but would lock in place and couldn't be easily removed. After some investigation, we found that both mating parts had problems. If either one of the conditions existed by itself, the parts still functioned properly, but the combination of both conditions caused the problem. In this case, actions were taken on both parts to ensure there would be no recurrence.
This is not two separate things, imo. The problem is in the "assembly." The design of the interface is the root cause. There may be instances where two (or more) things work in concert to cause a bad thing to happen, but it's still one instance.
 
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howste

Thaumaturge
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This is not two separate things, imo. The problem is in the "assembly." The design of the interface is the root cause. There may be instances where two (or more) things work in concert to cause a bad thing to happen, but it's still one instance.
That's one way to look at it. The problem was that one part couldn't be removed from the other. The cause is that a sharp corner on one part hung up on a perpendicular flat surface on the other. If I stop there, then what you say is true.

That's still a surface cause though. If dig deeper, I find that the cause of the interface problem is twofold: 1) a missing chamfer on one part, and 2) a flat surface that should have been rounded on the other. Both parts (from different suppliers) had changed slightly from the original design. Each supplier had a different cause for why their part changed.

By the way, the USB interface design is an industry standard and is outside the control of the organization. It's designed to hold the cable in place and requires some level of force to remove it.
 
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Jim Wynne

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That's one way to look at it. The problem was that one part couldn't be removed from the other. The cause is that a sharp corner on one part hung up on a perpendicular flat surface on the other. If I stop there, then what you say is true.

That's still a surface cause though. If dig deeper, I find that the cause of the interface problem is twofold: 1) a missing chamfer on one part, and 2) a flat surface that should have been rounded on the other. Both parts (from different suppliers) had changed slightly from the original design. Each supplier had a different cause for why their part changed.

By the way, the USB interface design is an industry standard and is outside the control of the organization. It's designed to hold the cable in place and requires some level of force to remove it.
It seems like one or both suppliers' parts weren't in accordance with the standard. That's the root cause. USB sockets and connectors that are made in accordance with standard will function as intended.
 
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howste

Thaumaturge
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It seems like one or both suppliers' parts weren't in accordance with the standard. That's the root cause. USB sockets and connectors that are made in accordance with standard will function as intended.
In a perfect world, parts made to the standard will function as intended. In this case, both parts met the industry standard. However, neither part was the same as its approved first article.

If you want to say there's one common cause, "nonconforming parts," then you can certainly say that. That's still dealing with a high-level cause though, not the root cause(s). In order to prevent nonconforming parts, we need to know why the parts are nonconforming. In this case, two separate causes in two separate companies.
 

Jim Wynne

Leader
Admin
In a perfect world, parts made to the standard will function as intended. In this case, both parts met the industry standard. However, neither part was the same as its approved first article.
If both parts met the standard, they would mate and un-mate as designed.

If you want to say there's one common cause, "nonconforming parts," then you can certainly say that. That's still dealing with a high-level cause though, not the root cause(s). In order to prevent nonconforming parts, we need to know why the parts are nonconforming. In this case, two separate causes in two separate companies.
There are two different root causes because there are two different parts involved, manufactured in different processes. But there's one root cause for each defective part no matter how you look at it.
 
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