Dear,

I am working in a manufacturing organization and where I calibrate the tools (vernier, micrometers etc.) from an outside Lab. Now if I want to start the calibration of these tools in-house so, what will be minimum requiremests for this?
Also it is mentioned here that I have calibrated gauge blocks so please tell me that using these blocks, simply I can calibrate my tools or not. Please guide me in detail

Dear,

I am working in a manufacturing organization and where I calibrate the tools (vernier, micrometers etc.) from an outside Lab. Now if I want to start the calibration of these tools in-house so, what will be minimum requiremests for this?
Also it is mentioned here that I have calibrated gauge blocks so please tell me that using these blocks, simply I can calibrate my tools or not. Please guide me in detail

To calibrate your measuring equipment on your own, you need following things:

1)A master gauge or instrument which is calibrated by an acredited laboratory.
2)The least count /precision of the master should ideally be 1/10 of the least count of your instrument.
3)The environement of the measuring room should be controlled as required in calibration standard.
4)You shuld document a procedure of calibration for the instrument in question specifying method of calibration and acceptable variation.
5)The acceptable variation should be capable of achieving the precision required by your product.
If you have the above five things, nobody can stop you from doing your own calibration. Please note the key here is, you can fix your own precision level depending on your product.
The calibration standards are designed for the aerospace industry for which you donot have to waste money.
V.J.Brahmaiah

<snip>The calibration standards are designed for the aerospace industry for which you do not have to waste money.
V.J.Brahmaiah

What do you mean? :confused:

Stijloor.

What do you mean? :confused:

Stijloor.
When my product tolerance is +/- 0.5 mm should I send my verniers and micrometers to certified laboratory and spend extra money on that instead of calibrating at home? In my earlier post I have listed 5 conditions for self calibration.
v.j.brahmaiah

Dear,

I am working in a manufacturing organization and where I calibrate the tools (vernier, micrometers etc.) from an outside Lab. Now if I want to start the calibration of these tools in-house so, what will be minimum requiremests for this?
Also it is mentioned here that I have calibrated gauge blocks so please tell me that using these blocks, simply I can calibrate my tools or not. Please guide me in detail

You are at full liberty to go for in-house calibration. Brahmaiah has adequately briefed you on this. Another important thing is, that your lab people must be trained, preferably from an accreditated laboratory.

Umang :D

When my product tolerance is +/- 0.5 mm should I send my verniers and micrometers to certified laboratory and spend extra money on that instead of calibrating at home? In my earlier post I have listed 5 conditions for self calibration.
v.j.brahmaiah

I understand...I was more interested in your "Aerospace" bit...

Stijloor.

I understand...I was more interested in your "Aerospace" bit...

Stijloor.
Aerospace Industry is like my mother. I was trained and worked there during the first ten years of my service.
I hold it in high regard.
V.J.Brahmaiah

To calibrate your measuring equipment on your own, you need following things:

1)A master gauge or instrument which is calibrated by an acredited laboratory.
2)The least count /precision of the master should ideally be 1/10 of the least count of your instrument.
3)The environement of the measuring room should be controlled as required in calibration standard.
4)You shuld document a procedure of calibration for the instrument in question specifying method of calibration and acceptable variation.
5)The acceptable variation should be capable of achieving the precision required by your product.
If you have the above five things, nobody can stop you from doing your own calibration. Please note the key here is, you can fix your own precision level depending on your product.
The calibration standards are designed for the aerospace industry for which you donot have to waste money.
V.J.Brahmaiah

Some of these statements are inaccurate!!

Calibration is a science which has application even at the level of the traffic police, performing speed checks and enforcement. Many people think they are doing calibration 'in-house' but don't posses many competencies (not just training) or the resources to perform calibration and waste money that way. Often they don't ask an outside lab for the correct service and take what they are given, but that's not a good reason to take calibration 'in-house'.

I believe your statement regarding the aerospace industry underlies your basic misunderstanding of the science of calibration;

Comment # 3 - Environmental conditions don't have to be 'controlled', they must however be known. There are many situations where money is wasted on a controlled envronment room, just for a few hand tools!

Comment # 4 - Is any old procedure going to be OK? If you calibrate an outside 0-25mm micrometer, for example, is any position along the scale acceptable, or how many should be used etc? There's a lot more to be considered than simply writing down what someone thinks should be done!

In #5 - What do you mean? How is a person to determine acceptable variation? Should someone calculate the uncertainty of measurement for the device? Peform linearity, bias and stability studies, is this what you mean?

Without clear understanding of the nature of calibration and the requirements for an effective system, the so called savings of doing calibration in-house can soon be lost through incorrect calibrations, wasted time and the negative effects on product and customer satisfaction!

<snip>The calibration standards are designed for the aerospace industry for which you do not have to waste money.
V.J.Brahmaiah

Let me try again. Calibration standards are NOT developed for the aerospace industry ONLY. They are developed and available for all industries that deploy measuring and testing devices. As an auditor, I want to know what sources of information are used to develop a calibration program.

Stijloor.

Some of these statements are inaccurate!!

Calibration is a science which has application even at the level of the traffic police, performing speed checks and enforcement. Many people think they are doing calibration 'in-house' but don't posses many competencies (not just training) or the resources to perform calibration and waste money that way. Often they don't ask an outside lab for the correct service and take what they are given, but that's not a good reason to take calibration 'in-house'.

I believe your statement regarding the aerospace industry underlies your basic misunderstanding of the science of calibration;

Comment # 3 - Environmental conditions don't have to be 'controlled', they must however be known. There are many situations where money is wasted on a controlled envronment room, just for a few hand tools!

Comment # 4 - Is any old procedure going to be OK? If you calibrate an outside 0-25mm micrometer, for example, is any position along the scale acceptable, or how many should be used etc? There's a lot more to be considered than simply writing down what someone thinks should be done!

In #5 - What do you mean? How is a person to determine acceptable variation? Should someone calculate the uncertainty of measurement for the device? Peform linearity, bias and stability studies, is this what you mean?

Without clear understanding of the nature of calibration and the requirements for an effective system, the so called savings of doing calibration in-house can soon be lost through incorrect calibrations, wasted time and the negative effects on product and customer satisfaction!
Most medium and large companies do their own calibration.In many cases we need a second set of gauges when we depend on outsiders.One more important reason against outside calibration is that we donot have any control on them. When the workload is heavy they may dilute procedures and quickly prepare certificates and return the instruments.
Unfortunately greed has entered into every business.
V.J.Brahmaiah

Most medium and large companies do their own calibration.In many cases we need a second set of gauges when we depend on outsiders.One more important reason against outside calibration is that we donot have any control on them. When the workload is heavy they may dilute procedures and quickly prepare certificates and return the instruments.
Unfortunately greed has entered into every business.
V.J.Brahmaiah

In my 25+ years, I've not found this to be the case - when you say 'most' are you describing Indian companies? I'm trying to be sensitive to your geographical situation. I really don't understand your comment regarding 'control' over a lab either! What do you expect to see in place?

What you say happens at outside labs happens more internally, in my experience! Indeed, many internal labs are fearful of someone actually 'uncovering' their scheme to make work for themselves! I have found such a case where the lab tech had set an impossibly frequent recall so he could justify working over-time to 'catch up' with the backlog of calibration. This was because there was no-one in management who knew enough about effective gauge management to know this guy was lying!

During my audit he was sweating profusely as I asked all the applicable questions to have him demonstrate his data-backed decisions for his recalls. Needless to say, once I'd finished explaining to his boss what should have been happening, they started to save a small 'mint' of money......

Once again, I find your comments to be very inconsistent. You previously suggested using an accredited lab - of which one of the ISO/IEC 17025 requirements is to demonstrate freedom from such commercial pressures!

In my 25+ years, I've not found this to be the case - when you say 'most' are you describing Indian companies? I'm trying to be sensitive to your geographical situation. I really don't understand your comment regarding 'control' over a lab either! What do you expect to see in place?

What you say happens at outside labs happens more internally, in my experience! Indeed, many internal labs are fearful of someone actually 'uncovering' their scheme to make work for themselves! I have found such a case where the lab tech had set an impossibly frequent recall so he could justify working over-time to 'catch up' with the backlog of calibration. This was because there was no-one in management who knew enough about effective gauge management to know this guy was lying!

During my audit he was sweating profusely as I asked all the applicable questions to have him demonstrate his data-backed decisions for his recalls. Needless to say, once I'd finished explaining to his boss what should have been happening, they started to save a small 'mint' of money......

Once again, I find your comments to be very inconsistent. You previously suggested using an accredited lab - of which one of the ISO/IEC 17025 requirements is to demonstrate freedom from such commercial pressures!
Large companies can afford to have their own calibration fecilities.There is nothing unusual about it.Only sophisticated instruments may have to be sent to National Laboratories.
But outsourcing has become part of working culture in some countries.
V.J.Brahmaiah

Large companies can afford to have their own calibration fecilities.There is nothing unusual about it.Only sophisticated instruments may have to be sent to National Laboratories.
But outsourcing has become part of working culture in some countries.
V.J.Brahmaiah

True, large companies can afford to have their own labs. I didn't say there was anything unusual about it. However, even unsophisticated equipment - those used as calibration 'master' standards - are still required to be calibrated against national standards, here that's available. This is, in the majority of cases I've found, carried out by an outside lab. Outsourcing of calibration has been common for longer than I've been around this industry.

Could you help others to understand how this can help the OP with their quest for information about doing in-house calibrations? In earlier posts you made some statements but I am unable to see how your later points clarify what your point of view is. Would you shed some further light on these statements?

Dear,

I am working in a manufacturing organization and where I calibrate the tools (vernier, micrometers etc.) from an outside Lab. Now if I want to start the calibration of these tools in-house so, what will be minimum requiremests for this?
Also it is mentioned here that I have calibrated gauge blocks so please tell me that using these blocks, simply I can calibrate my tools or not. Please guide me in detail

Hello, Rizy!

The short answer is yes; you can calibrate your own instruments, given you have sufficient standards, procedures, and adequate control of the process.

The thing is, make sure you have an appropriate strategy for wanting to do it. There are a lot of hidden costs with performing your own calibrations. Also, those calibrations come around every interval, so it's a long-term commitment of time and money to calibrate in-house.

There are different grade of gauge blocks with different accuracies and material. Obviously the better grade and material will cost more money. You will need to get your standards verified at a periodic interval, so assume you will not have capabilities during that time, or buy a second set of standards to fill in.

Dear Rizy, Hope some of this helps as I started off in your shoes 15 yrs. ago. Don't know if your Company is certified or not but in ISO 9001 (sec. 7.6) Control of monitoring and measuring equipment it's pretty well laid out for you. I've attached what I use at my company for a calibration card. One card is needed for every tool and also a copy of the master where all the tools calibrated are listed. You'll also need to have a procedure for this.

Good luck. :bigwave:

True, large companies can afford to have their own labs. I didn't say there was anything unusual about it. However, even unsophisticated equipment - those used as calibration 'master' standards - are still required to be calibrated against national standards, here that's available. This is, in the majority of cases I've found, carried out by an outside lab. Outsourcing of calibration has been common for longer than I've been around this industry.

Could you help others to understand how this can help the OP with their quest for information about doing in-house calibrations? In earlier posts you made some statements but I am unable to see how your later points clarify what your point of view is. Would you shed some further light on these statements?
If you are specific on any perticular comment I have made I will clarify further. If not I will correct myself. There is no prestige involved.
V.J.Brahmaiah:agree:

Hello Rizy!

AndyN and BradM have given good responses already.....there has been a lot of good discussion, so I may not be able to add much.

If you are going to cal your own calipers, etc., inside, there are a few things you need in order to have a valid calibration.

First, a cost-benefit analysis. If you have less than 300 items of a similar type (e.g., calipers) you will likely find it less expensive in the long run to have the devices calibrated by an accredited laboratory.

Your gage blocks need to be calibrated by an accredited laboratory, and make sure you get the uncertainty of the measurements. It will cost more, but you need the information.

Next, you must have a valid procedure. Use one that is published by an appropriate source, or else if you develop your own it needs to be validated.

For calipers and similar, if the environment is not controlled (e.g., 20 C +/- 2 C) then you must take the temperature variation into consideration in YOUR uncertainty calculations. This is known as thermal coefficient of expansion (or contraction).

You must monitor and record the environmental conditions, whether controlled or not.

The personnel performing the calibration must be trained in the procedure and truly should be trained in uncertainty and at least basic Metrology concepts.

You need to keep the reading from the calibration and document the traceability information.

You MUST have uncertainty for the calibrations you do, or there no traceability of the calibration. If you are not trained in uncertainty calculations, then you need to get training.

NEVER, EVER, touch the gage blocks with fingers, and if a manager or similar makes like they will, hit their knuckles with a stick. Use gloves. White cloth is most commong but latex and similar are good too. The gloves serve exactly two functions: prevent finger oil from changing the block's value, and slow down the thermal transfer from the fingers.

It has been pointed out that Metrology is a science, and in fact is one of the three oldest recorded sciences.

Hope this helps.

I've been away from calibrations for a bit but the statements you made are what i've always known. Question is, what standard can I find them in to prove it to a "non-believer"?
Thanks