I was asked to look at profiles on an overlay. These profiles were observed to be significantly outside the tolerance band (3x the tolerance specified on print). Now one might argue this is a non-functional feature and therefore should not be rejected. I would prefer to rely on my gage to determine whether the part is acceptable or not (obviously is does not conform to print). I was not involved in the design process and have not attended surgeries, to say definitively what is functional and what is not.

I would like to be able to rely on the gages and not make exceptions because one feels it will be ok. Do I have a foot to stand on here? Or is it the nature of the beast that Quality must add gut-feel or context before rejecting a part?

My proposed solution is to adjust the gage (overlay) to accept such parts if indeed such parts are acceptable. Then I can rely on my gage again.

My proposed solution is to adjust the gage (overlay) to accept such parts if indeed such parts are acceptable. Then I can rely on my gage again.

Absolutely - but I wouldn't make this decision without some approval from engineering or your customer.

I was asked to look at profiles on an overlay. These profiles were observed to be significantly outside the tolerance band (3x the tolerance specified on print). Now one might argue this is a non-functional feature and therefore should not be rejected. I would prefer to rely on my gage to determine whether the part is acceptable or not (obviously is does not conform to print). I was not involved in the design process and have not attended surgeries, to say definitively what is functional and what is not.

I would like to be able to rely on the gages and not make exceptions because one feels it will be ok. Do I have a foot to stand on here? Or is it the nature of the beast that Quality must add gut-feel or context before rejecting a part?

My proposed solution is to adjust the gage (overlay) to accept such parts if indeed such parts are acceptable. Then I can rely on my gage again.


Hello Poohbear,

It looks that we have two issues (processes) here that appear to be "mixed":
1. Monitoring and measurement of product (Inspection and test). Any time a product does not meet the specification, it is deemed "nonconforming." I'm sure your organization has a way to record this. The time to engage in "negotiations" regarding what to do with it, should not be during inspection.
2. Control of nonconforming product. Once the nonconforming product has been identified and recorded, authorized persons should review the product and decide on what to do with it (disposition). Could be scrap, rework, get a waiver from the customer, etc.

If you start mixing up the two activities, you'll create a mess.

What do your procedures say? Sometimes, what's been agreed upon way back is not necessarily what's happening today.

Hope this helps a little.

Stijloor.

Absolutely - but I wouldn't make this decision without some approval from engineering or your customer.


Hi CarolX,

Indeed! But that's a possible corrective action that follows control of nonconforming product.

I was asked to look at profiles on an overlay. These profiles were observed to be significantly outside the tolerance band (3x the tolerance specified on print). Now one might argue this is a non-functional feature and therefore should not be rejected. I would prefer to rely on my gage to determine whether the part is acceptable or not (obviously is does not conform to print). I was not involved in the design process and have not attended surgeries, to say definitively what is functional and what is not.

I would like to be able to rely on the gages and not make exceptions because one feels it will be ok. Do I have a foot to stand on here? Or is it the nature of the beast that Quality must add gut-feel or context before rejecting a part?

My proposed solution is to adjust the gage (overlay) to accept such parts if indeed such parts are acceptable. Then I can rely on my gage again.

You can't change the gage without changing the controlling specifications (the drawing). What you need is some sort of MRB process wherein questionable material is evaluated by a cross-functional group (engineering, quality, production, purchasing, e.g.) and a determination as to fitness for use is made on a case-by-case basis. When a decision to "use as is" is made, it should also be accompanied by either a drawing change to accommodate the expanded tolerance, or a written "deviation" that authorizes use of the nonconforming parts, specifies the quantity that may be used, and triggers the CA system.

I'm a little concerned about your reference to not having "attended surgeries," not knowing whether you refer to "surgeries" figuratively or literally. If you're dealing with medical devices used in surgery, you definitely need to clean up your process of dealing with NC material.

I would like to be able to rely on the gages and not make exceptions because one feels it will be ok. Do I have a foot to stand on here? Or is it the nature of the beast that Quality must add gut-feel or context before rejecting a part?



Sorry Poohbear - I really missed your question here. Your thinking is correct - that you should rely on the gages and not make exceptions. Those decisions need to be made by the folks that are paid to make those decisions - such as the responsible engineer.

Now, many times we do use our "gut" to make decisions whether to reject something - for example - one of our customers makes retail store shelves and displays. I know this customers expectations - much better to look good than to measure out to spec - so I have approved out of tolerance conditions in the past.

On the other hand - I have a customer that I won't make the call on - I leave that to the others.

Thank you all for your responses.

We do indeed have a rather comprehensive QMS. I am not confident we stick 100% to it. I believe that this in fact may be the source of my frustrations.

If I understand all of you correctly, the ground I have to stand on is defined in our specs and requires a formal deviation process to be followed, for example written waiver with appropriate signoffs, WHENEVER a part does not meet print (dimensional issues).

I am still not fully satisfied however as I begin to understand my original question better. Back to the overlay example:
My Quality Manager might suggest that a certain amount of deviation is ok because that area or feature is not functional. In such a case, can I argue/require that the profiles be removed from the overlay or the tolerance opened up in that area (provided of course the print has been changed)? Any changes to be made, would follow formalized process, of course.

Perhaps another way of putting it, can Quality make a dimensional call (no matter how small the deviation)? Is that left to internal, company policy?

When deviating from specification we should be first getting the okay from the customer. Sometimes prints have errors or are perhaps too strict for the part's purpose.

But a print is a print, and we don't get to choose which among its features to obey. Lest we lose our customer's confidence we should communicate these concerns instead of sending parts that don't conform--even if we honestly think the parts are functionally okay.

...

If I understand all of you correctly, the ground I have to stand on is defined in our specs and requires a formal deviation process to be followed, for example written waiver with appropriate signoffs, WHENEVER a part does not meet print (dimensional issues).

I am still not fully satisfied however as I begin to understand my original question better. Back to the overlay example:

My Quality Manager might suggest that a certain amount of deviation is ok because that area or feature is not functional. In such a case, can I argue/require that the profiles be removed from the overlay or the tolerance opened up in that area (provided of course the print has been changed)? Any changes to be made, would follow formalized process, of course.

Perhaps another way of putting it, can Quality make a dimensional call (no matter how small the deviation)? Is that left to internal, company policy?


You have an agreement with your customer to produce parts to print, and they agree to pay for them if they meet print.

If you send them something that is not to print, they technically do not have an obligation to buy the parts. You have violated the agreement.

Does your QM really want to stick his neck out that far? It would be better for him to use his expertise to make the process more capable so it meets print. Or, work out an agreement with the customer as to a more appropriate or workable dimension, if not capable.