Monitoring and Measurement - Small shop making tooling for the foundry industry

[dhulke]

Monitoring and Measurement

I work at a small machine shop (15 workers) making prototype and production tooling for the foundry industry, and CNC machined parts. We are in-process of creating an ISO 9001:2000 system, but are having difficulties getting past the calibration/verification of monitoring and measuring equipment. Every employee has their own inspection control equipment and the shop has many sets of mics, gages, indicators, etc. and a cmm. Our biggest concerns are: what we need to calibrate (does it have to be all employee equipment or just final inspection equipment), can we do calibration off of a set of standards (i.e. certified gage blocks) or do we have to bring in an outside source. We are looking for a very simple and cost effective approach to completing this. Any thoughts.

 

[Bob_M]

I work at a small machine shop (15 workers) making prototype and production tooling for the foundry industry, and CNC machined parts. We are in-process of creating an ISO 9001:2000 system, but are having difficulties getting past the calibration/verification of monitoring and measuring equipment. Every employee has their own inspection control equipment and the shop has many sets of mics, gages, indicators, etc. and a cmm. Our biggest concerns are: what we need to calibrate (does it have to be all employee equipment or just final inspection equipment), can we do calibration off of a set of standards (i.e. certified gage blocks) or do we have to bring in an outside source. We are looking for a very simple and cost effective approach to completing this. Any thoughts.

Note: I'm far from an expert but here my $0.02 anyways...

Certified Blocks: We use them to verify caliper and mics in house. I send the blocks out annual to get verified but a calibration lab.

Since I personally an not we learned or experienced with calibration, we send pretty much everything else out like Indicators, Height Masters, Ring Gages, etc.

Your calibration system does not need to be very complex, but you do need to follow "standard" calibrating techniques and requirements. I can't quote them, but I know they exist.

Search the this site, there have been plenty of good topics on in-house calibrations and the minimal requirements for doing them.

Employeed owned gages are typically verified/calibrated if they are used to ensure product quality. It seems many people here agree those calibrations can NOT be done by the tool owners. They should be done by somebody using the company's equipment or a calibration lab. I suppose the tool owners could get them certifed by a lab, but how realistic that?

 

[Claes Gefvenberg]

Hello dhulke and welcome to the Cove .

I can see your problem. You are a small shop and considering what you do you need to do a lot of measuring. If you need to calibrate the lot of it, it will no doubt strain your recources.

One question: How do you handle this today? You already need to make certain that you produce acc. to spec...

Anyway, here it is: Clause 7.6:

The organization shall determine the monitoring and measurement to be undertaken and the monitoring and measuring devices needed to provide evidence of conformity of product to determined requirements.

Simply put: You have to get anything used for final inspection calibrated. As for the rest: That depends on you. Anytime you use uncalibrated equipment you take a (hopefully calculated) risk.

Equipment you seldom use can be calibrated prior to use: 7.6a:

Where necessary to ensure valid results, measuring equipment shall
a) be calibrated or verified at specified intervals, or prior to use...

Hope this helps?

/Claes

 

[Craig H.]

dhulke:

Welcome!

Although it may not be required to calibrate in-process measurement equipment, to expand on what Claes said, you could be taking a fairly good sized risk, IMO. If you use an out-of-calibration mic to mill a part, say, then a calibrated mic for final inspection, what are the chances that the part will fall out of spec using the calibrated instrument?

Then, if the part fails, what are the costs (material, labor, etc.) of scrapping it?

If it is worth measuring, it is worth measuring with calibrated equipment.

Craig

 

[Jimmy Olson]

Hi Dhulke

Both posts have good recomendations.

As far as what you need to calibrate, you should look at what is being measured and where or when. Basically, if you are making a measurement to determine the acceptability of the product then the tool should be calibrated.

If you have qualified personnel, you can do all your calibrations in house with a set of standards. Then you just need to have your standards done by an outside source. If this is an option, it will probably save money, depending on the people you have versus the amount of time spent calibrating.

That's just the short and simple answer to your questions

As already mentioned, there is plenty of information here and feel free to ask any specific questions.

 

[Randy Stewart]

We only send out our gage blocks for cal and the CMM's are done by the OEM. We do internal verifications of all employee owned gages annually and have them in an access data base. We have been operating this way for around 4 years now and have never received an NC on calibration. But remember, we're in the prototype stamping business and the tolerances may not be as tight as what you're required to hold.
I need to add that the company does not supply gages to the shop floor, other than 6 sets of mics, height gages and calipers (2 at each facility) they are all employee owned (approximately 1500 gages).

 

[Bob_M]

We only send out our gage blocks for cal and the CMM's are done by the OEM. We do internal verifications of all employee owned gages annually and have them in an access data base. We have been operating this way for around 4 years now and have never received an NC on calibration. But remember, we're in the prototype stamping business and the tolerances may not be as tight as what you're required to hold.
I need to add that the company does not supply gages to the shop floor, other than 6 sets of mics, height gages and calipers (2 at each facility) they are all employee owned (approximately 1500 gages).

Randy I just skimmed your calibration document and I really like this section from the manual gages:

TOOLS THAT ARE ON COMPANY PROPERTY BUT ARE NOT USED, MUST BE CALIBRATED, LABELED AND SEALED IN BAG. AT NEXT CALIBRATION DUE DATE, IF BAG IS STILL SEALED, MAKE NEW LABEL AND ATTACH TO GAGE THEN RESEAL.

I may try to implement this idea when I get a chance. It might only be for a few gages, but it would still be a time saver. (Even better we have VCI - anti-corrosion bags and a bag sealer in house!!!)

Would you mind posting your caliper and mic worksheet form?
Do you have calipers with ID pinchers and/or depth rod? How do you check them?

 

[Randy Stewart]

We used something like the Seal-A-Meal thing. It works great.

Yes we do use both OD & ID calipers some with depth checks. This is the main tool that gets the "Calibration Rejection W/Exception Use" sticker. They maybe ok for an ID check but the depth rod is too bent or broken to be used.

 

[Shaun Daly]

dhulke,

You dont say what sector you are in. If your customers send you Supplier Quality Assurance Manuals, read through those.

Our suppliers are very careful to state that all gauges used for production or testing must be reguarly calibrated according to use.

Personally I would calibrate ALL gauges - If you are using them for M/C setups etc.

If you dont, one day, the day will come when you wish you had.

 

[dhulke]

calibration

Thanks to everyone who replied to my last post...i have been away for a while and have not been able to log on recently. anyway, being a machine shop we basically use indicators, mics, gage blocks, etc. We have been arguing though as to how calibration works. From what I have read about calibration and traceability, we cannot certify a gage block and then verify another gage block, and then use both to verify equipment. we can only use the certified block or else the traceability chain is broken. secondly, if it has to be calibrated, it needs to be done in a controlled environment, by someone who has been trained in that area. Making us able to verify, but not calibrate. am i wrong about this?