Request: Procedures for BASIC in-house Calibrations - Small Company

[Bob_M]

Info First:
We are relatively small company that uses mainly Calipers, Micrometers, and Tape measures in the productions/receiving areas.
We have a very basic work instructions that tells me how to calibrate/verify these types of gages in-house. I also received some quick training on how to do them before our last quality manager left.
The procedure/work instructions overall are OK, but just barely.

With out BUYING more standards or going to more training (low $$ right now), can any one provide some other their procedures for calibrating there equipment in house?

Also what kind of standards/publications or training could I seek out?

Our program works so far, but I have no real training or background in this area, I'm a bit concerned about the long term for our company and MYSELF.

Thanks Bob_M

 

[tomvehoski]

What kind of inspections are you performing? How tight are your tolerances?

Basic checks on calipers and micrometers with certified gage blocks are usually sufficient. You don't need to spend a fortune to make sure your caliper is correct. Some things may not even need to be checked. If your receiving person is using a caliper to tell if a piece of bar stock is 1.25 or 1.5 OD, you don't need to calibrate that caliper.

Production gages may not need to be calibrated (at least not very often) if you use inspection gages for a final check. If everything goes through a CMM or other inspection later, you may determine that the risk of not catching a bad part in production due to lack of calibration is less than the cost it would take to calibrate every device.

I often rely on a single page form that shows where a caliper should be checked (i.e. 0, 2, 4, 6" +/-.0005) and records the actual readings before and after calibration.

It does not have to be fancy and expensive to work.

Tom

 

[Ken K]

One question...are you asking per ISO 17025 or QS/TS? Will make a difference in the answer to your question.

 

[Bob_M]

Ken K said:

One question...are you asking per ISO 17025 or QS/TS? Will make a difference in the answer to your question.

I'm asking for ISO9K2K (upgrading from 1994).

tomvehoski:

Most CURRENT tolerances are only 3 places (inches). Not very tight, but critical on a few parts/materials.

We do incoming material thickness/width inspections (most common type) with calipers and micrometers.

We do first piece, in-process, last-piece and final (when necessary), using mainly calipers, micrometers, and tape measures. NO CMMs. A few "fixtures" or go-nogo type gages.

I know we don't need rocket science quality calibrations, but I do want a program that will work for the long term (ie tighter tolerance parts in the future).

We/I check caliper/mics against (externally) calibrated gage blocks. I know this works, but SHOULD we be doing more/better?

 

[Ken K]

I know this works, but SHOULD we be doing more/better?

If you feel your current system works and your auditor feels the same, why do you feel you should be doing more/better?

If you feel you should be doing more, get a copy of the MSA manual. It will give you many idea's as far as things you could be doing.

Have you ever considered having an outside calibration lab do your calibrations and you concentrate on verifications? Might be an option.

 

[Bob_M]

Ken K said:

If you feel your current system works and your auditor feels the same, why do you feel you should be doing more/better?

If you feel you should be doing more, get a copy of the MSA manual. It will give you many idea's as far as things you could be doing.

Have you ever considered having an outside calibration lab do your calibrations and you concentrate on verifications? Might be an option.

I probably should have the MSA manual. (Adds to wishlist).

We send out some of less BASIC equipment, or stuff I have no personal idea how to calibrate/verify.

I'm asking for improvement suggestions, because I don't know if our programs is good enough. It may be good enough for now, but if I'm calibrating/verifying incorrectly, over time the equipment may not truely be in spec.

Besides, I want to be more educated if possible. For my current job and myself.

 

[tomvehoski]

It sounds like your calibration system is probably fine. You may want to look at the MSA manual to see if gage R&R studies or similar will be a benefit. From what I have seen it is usually more expensive to outsource basic calibration - $30-$40 per mic or caliper. As long as your gage blocks are NIST traceable, you should be fine.

If you want additional training, you might want to look at ASQ. Perhaps a Certified Mechanical Inspector or Calibration Tech would give you some additional ideas. Local sections offer refresher courses at relatively reasonable prices. I have not gone for either of these certificates, so I don't know everything about the body of knowledge.

If you have some money to spend, I would probably look at upgrading the equipment to something that can be more precise and/or efficient to use. I know we save a ton of time at one place I worked when we purchased an advanced digital height gage - cut inspection time way down. It might help you get those tighter tolerance part contracts if you can show that you have the technology to inspect tighter tolerances.

Tom

 

[Bob_M]

tomvehoski said:

It sounds like your calibration system is probably fine. You may want to look at the MSA manual to see if gage R&R studies or similar will be a benefit. From what I have seen it is usually more expensive to outsource basic calibration - $30-$40 per mic or caliper. As long as your gage blocks are NIST traceable, you should be fine.

If you want additional training, you might want to look at ASQ. Perhaps a Certified Mechanical Inspector or Calibration Tech would give you some additional ideas. Local sections offer refresher courses at relatively reasonable prices. I have not gone for either of these certificates, so I don't know everything about the body of knowledge.

If you have some money to spend, I would probably look at upgrading the equipment to something that can be more precise and/or efficient to use. I know we save a ton of time at one place I worked when we purchased an advanced digital height gage - cut inspection time way down. It might help you get those tighter tolerance part contracts if you can show that you have the technology to inspect tighter tolerances.

Tom

NOPE no money to spend at the moment.
We do have all digital calipers, some digital mics, digital height gage.

The gages are good enough for current product requirements. I just don't think my knowledge is enough, especially if we were to get higher-tech product lines or products.
*shrug*

 

[Ken K]

From what I have seen it is usually more expensive to outsource basic calibration - $30-$40 per mic or caliper.

Our current cost for calipers and mics is $12.00 per gage per year. Digital height gage is not much more. Considering time spent verifying or calibrating it might be a wash. And the uncertainties will be calculated. A2LA accredited lab.



As far as training goes, Mitutoyo has seminars which are reasonably priced. The materials you receive are worth admission.
Have you checked for classes at a local Technical College?

I would definately get the MSA manual. Gage R&R's should give you an indication how good you system is.

 

[AlbertPaglinawan]

hello,

you might want to add the JIS Handbook Mechanical Instrumentation on your wishlist. we purchased a copy and it is great! it gives a detailed procedure in calibrating micrometers, calipers, gauges, etc. (ex, measuring method for parallel screw gauge). This really is a must for dimensional metrology. Unless there is an equivalent book in the U.S. (This book is from Japanese Standards Association translated in english)

cheers!

-jahar