Controlling the Design of Gauges - Requirements?

[M Greenaway]

Hi Guys

Should we have a formal documented procedure (talking QS9000 here) for the control of the design of gauges (i.e. special gauges we make in-house) ?

Or if we operated a proper MSA programme on gauges would that negate the need for such a procedure ?

Please advise your thoughts as I am currently in two minds (maybe more).

[Marc]

I would look at what's happening now. I'm not sure how you can 'control' a fixture design process outside of the standard design process template. Hiring / job criteria may also play a part. That is to say, is a requirement of the position to have experience in gage design? There is the benefit of standardization any time you document a process, including a design process.

As far as an R&R, I'm not sure how that would apply. Amongst other aspects, an improperly designed fixture may give you a good R&R but by design is not even really measuring what you think you're measuring. Especially when you look at GD&T issues in some designs and other aspects such as material flexability (e.g.: When is restraint necessary? Which surface do you restrain and why? Etc., etc.).

I see them as different issues entirely. The first thing I assume is that a gage / fixture is poorly designed and take a look for myself as to whether I think the gage / fixture designer knew what s/he was doing.

Are you currently having problems? Or are you thinking something else.

[M Greenaway]

Sorry for the delay in replying - been on my hols again.

This question really stems from internal audit findings. I could re-word it to suit ISO9001:2000 in that the gauge design 'process' is not adequately defined. i.e. when I ask who designs gauges the answer is practically 'anyone we can get hold of' (i.e. internal 'product' engineering staff or external sub-contractors), when I ask where are master drawings kept the answer is 'dunno, some are here but Im not sure if they are masters', when I ask who has approval authority for gauge design I get a complete blank expression, etc, etc.

Now I think this is a valid audit finding, but also a recent complaint has also highlighted deficiency in the gauge design process (I try to align my audit findings with real current business issues).

Now is my audit finding valid, or are gauges a special case if we perform R&R studies and the like ?

I am kinda thinking this process (procedure) needs defining as it appears anyone can create a new gauge, anyway they like - but I also recognise that R&R, or more specific MSA studies are in effect an excellent design validation tool - hence does the process/procedure need defining if the output is effectively controlled via R&R or MSA.

Yours - still in two minds - MG

[Sam]

MG,
IMO, Gage design and gage control would be two distinctly different processes. Gage control is not a problem. It is well defined in the standard/specification.
Gage design is not. Should there be a procedure? IMO yes. It has been my experience in the past that most engineering/design departments maintain a set of design documents. Included in these documents is everything from material/component selection to design equations and test requirements.
I don't see how any design department could function without a set of design procedures. I know, someone is going to say, you will stifle my creativity. Not true, creativity without control is chaos.

As for valid audit finding, I would think it would only be valid if you could reference a paragraph number, otherwise it would be an "opportunity for improvement"