Corrective Action Reply to a Customer - Operator Error

[inspector 2s]

Newbie.

Hi guys/gals.

I am a recent member and was wondering if someone could come up with an answer for me.
We recently had a NC off our customer. The part was machined and one of the four M4 tapped holes was not tapped to depth. We do 100s of these and all are tapped by hand, the fitter just missed one, our customer will not accept human/operator error. This wasn't picked up at inspection as toleranced dimensions are the only sizes that are checked, the rest is visual. Anyone got any ideas for corrective action?

many thanks.

Insp 2s

[somashekar]

Welcome to the Cove inspector 2s ~~~

our customer will not accept human/operator error

We do 100s of these and all are tapped by hand,

What you say above is certainly contradicting and not in line with your customer's expectation.
When you do more, your fitter would again miss few, and this is not intentional. Your visual inspector will miss too, and again not intentional.
Can you make investment to have a drilling fixture to drill all 4 at one go ?
Like this one in the picture attached .....

[Jason PCSwitches]

You also need to look at your inspection process and how this was allowed to slip-thru.

Your probably doing a sample of the batch, so you may need to increase the sample size as corrective action. If you are not inspecting for the noted defect, you may want to start doing so as a part of your corrective action.

These things will happen but the point of a QMS is to improve your processes. This is an opportunity to do so. Human error is probably not the root cause; it's the inspection process.

[Bev D]

Perhaps this is a semantically quibble, but in this case human error is the cause. (while I am normally suspect of human error ,there are legitimate occurrences. Retraining or 'discipline' are almost never effective). The inspectIon process did not cause the defect, it failed to catch it. In "Apollo" language, it is the escape cause while human error is the physical or 'root' cause.

I think what your customer is probably looking for is a positive corrective action that will most likely involve some level of error proofing such as Someshaker has proposed...

[Jim Wynne]

In Reply to Parent Post by inspector 2s

Newbie.

Hi guys/gals.

I am a recent member and was wondering if someone could come up with an answer for me.
We recently had a NC off our customer. The part was machined and one of the four M4 tapped holes was not tapped to depth. We do 100s of these and all are tapped by hand, the fitter just missed one, our customer will not accept human/operator error. This wasn't picked up at inspection as toleranced dimensions are the only sizes that are checked, the rest is visual. Anyone got any ideas for corrective action?

many thanks.

used?

Can you clarify?

Insp 2s

You say that one of the holes "was not tapped to depth." I take this to mean that the hole was tapped, but not deep enough. You also say that the tapping is done by hand, but I'm not sure what that means either. Do you mean it's done by a machine, such as a drill press, and not in machine that actually makes the part, or do you mean that an actual hand tap is used?

[Mr.Happy]

Hi,

When you make 100s of those parts, why don't you switch to an automatic (CNC) process.
Then you only have to check the first and the last part (and any in between if you like).

[lego55]

In Reply to Parent Post by inspector 2s

Newbie.

Hi guys/gals.

I am a recent member and was wondering if someone could come up with an answer for me.
We recently had a NC off our customer. The part was machined and one of the four M4 tapped holes was not tapped to depth. We do 100s of these and all are tapped by hand, the fitter just missed one, our customer will not accept human/operator error. This wasn't picked up at inspection as toleranced dimensions are the only sizes that are checked, the rest is visual. Anyone got any ideas for corrective action?

many thanks.

Insp 2s

Hello,

Your customer might simply want one more "why" past "operator error." They might just be looking for the reason he/she didn't do what was needed. For example...

Is there a procedure the fitter did not follow? Or do you need a procedure?
Did the fitter get distracted? If so, by what and can it be prevented?

We once found out that our person who suddenly began making some errors kept forgetting their glasses. We just didn't ask the right questions. Another time, we found out our inspector was color blind and didn't notice the shade difference. We were able to put controls into place that helped each one.

Asking the right questions and finding the next reason might make it easier to prevent it next time.

Just my 's worth.

[inspector 2s]

In Reply to Parent Post by Jim Wynne

You say that one of the holes "was not tapped to depth." I take this to mean that the hole was tapped, but not deep enough. You also say that the tapping is done by hand, but I'm not sure what that means either. Do you mean it's done by a machine, such as a drill press, and not in machine that actually makes the part, or do you mean that an actual hand tap is used?

Thank you all for your response.
Jim, the four holes are drilled and part tapped on a CNC machine. They are not tapped to depth to avoid tap breakage, the holes are then tapped by hand with a tap wrench.
there are two tapped holes on each face of the component about 500mm apart.
We have been doing this part for over 7 years and this is the first time this has happened, I know it's technically a non conformance, but where does common sense kick in?