Process Error or Human Error? Your opinion, please

[Frank T.]

I have a question pertaining to a nonconformance.

Situation:

Parts were manufactured as required by all applicable procedures, work instructions, drawings, etc. at the start of the work order. The operator realizes they are short approx. 800 pcs. to complete the work order. The operator notifies supervisor, who notifies the material handler, who inturn, has to have material converted to a specific width to run through machine.
Not a problem.

In the mean time the operator tears down machine and sets up to run another job while the material is being converted, again not a problem.

After finishing the other job the machine is torn down and reset-up to run the remaining 800 pcs. The operator runs the 800 pcs. and brings the final piece to the quality dept. to be inspected.

The quality dept. inspects the final piece and realizes that one of the dimensions is oversize, remember at the start of the order everything was correct.

After further investigation it was found that one of the dimensions was apparently transposed, resulting in 800 pcs being scrapped.

My question is would this be considered a process error or human error?

I ask because in my opinion the process wasn't in error the person failing to follow the process was!?

***Note***
The operator is aware of the requirement to have a first piece checked any time a machine is set-up or in this situation resetup.

[DsqrdDGD909]

Is there a checklist for the operator to follow/initial?

How experienced/trained is this particular operator?

Is there a long delay in getting the first parts checked?

[Frank T.]

Is there a checklist for the operator to follow/initial?
There is a control plan that outlines what is to be accomplished.

How experienced/trained is this particular operator?
The operator has been doing this job for 11 yrs.

Is there a long delay in getting the first parts checked?
No, there is not a significant delay in getting the first part checked.

[CarolX]

IMHO - this was a process error.

Ask yourself - what could be improved in the process to prevent numbers from being transposed?

Could the set-up instructions be improved to prevent this?
Could the print be clarified to prevent this?
Could a differnt measurement technique be used to prevent this?
Could the set-up person benefit from some additional training to prevent this?

[Ajit Basrur]

This, according to me sounds like a system failure -

by the way you have described, it looks to me as if this LONE operator is responsible for everything ?

Does your system not have Verification or other team members from Quality take part in "In process QC" checking at frequent intervals of the process ? Also there should a system of checking the first shot and if this is ok, the rest of manufacturing to continue.

Would it be not a good practise to ensure that machine parameters once set are checked / verified by supervisor for confirmation ?

With all these points, I would say that the process is inadequate to detect failures - remember that Quality has to be built in the process and not tested for Quality.

[Benjamin28]

As with the others I would suggest this is entirely process error, particularly in the machine set-up there should be verification prior to running an entire lot. As suggested a first peice would work fine or some kind of poka yoke.

[Jim Wynne]

In Reply to Parent Post by Frank T.

I have a question pertaining to a nonconformance.

Situation:

Parts were manufactured as required by all applicable procedures, work instructions, drawings, etc. at the start of the work order. The operator realizes they are short approx. 800 pcs. to complete the work order. The operator notifies supervisor, who notifies the material handler, who inturn, has to have material converted to a specific width to run through machine.
Not a problem.

In the mean time the operator tears down machine and sets up to run another job while the material is being converted, again not a problem.

After finishing the other job the machine is torn down and reset-up to run the remaining 800 pcs. The operator runs the 800 pcs. and brings the final piece to the quality dept. to be inspected.

The quality dept. inspects the final piece and realizes that one of the dimensions is oversize, remember at the start of the order everything was correct.

After further investigation it was found that one of the dimensions was apparently transposed, resulting in 800 pcs being scrapped.

My question is would this be considered a process error or human error?

I ask because in my opinion the process wasn't in error the person failing to follow the process was!?

***Note***
The operator is aware of the requirement to have a first piece checked any time a machine is set-up or in this situation resetup.

It's impossible to say for sure from this vantage point where the cause lies. Carol raises some good questions, but given an optimized process it still might be possible for mental errors to happen, and then be compounded by failure to observe process requirements. Unless there's some method of foolproof error prevention, the best we can do sometimes is minimize and not eliminate the possibility of nonconformance. We should think in terms of process optimization (making it as good as it can be in view of known restraints) instead of process perfection.

[BradM]

In Reply to Parent Post by Frank T.

....The operator realizes they are short approx. 800 pcs. to complete the work order. The operator notifies supervisor, who notifies the material handler, who inturn, has to have material converted to a specific width to run through machine.
Not a problem.

IMHO, this is where the process may have some deficiencies. Not sure how thorough the verification is at this point, but this sounds like some opportunities for error. Is the notification written? When the conversion is made, is there a verification of proper machine setup? If the proper changeover process was followed, then the likelihood the equipment would have been set up correctly would be quite high.