Test equipment calibration cycle

[Thomas Magma]

I work for a small start up company, and we are trying to determine what we
can get away with for the period in which we calibrate our production test
equipment. Does anyone know who should define the calibration cycle of test
equipment used in production? Is it the manufacturer of the test equipment,
is it a ISO definition, can it be self defined by QA and if so, I'm guessing
that some customers will complain if they notice a 5 year cal cycle on their
calibration certificate which we provide to them.

So how is the best way to define a calibration cycle? For instance, we tie
all are signal generators to a 10 MHz GPS disciplined rubidium standard
which is said not to need calibration but still needs verification. So can
we only send our rubidium reference for verification once a year but extend
our signal generators out to 3 years?

Any thoughts?

Thomas

 

[scada]

I work for a small start up company, and we are trying to determine what we
can get away with for the period in which we calibrate our production test
equipment. Does anyone know who should define the calibration cycle of test
equipment used in production? Is it the manufacturer of the test equipment,
is it a ISO definition, can it be self defined by QA and if so, I'm guessing
that some customers will complain if they notice a 5 year cal cycle on their
calibration certificate which we provide to them.

So how is the best way to define a calibration cycle? For instance, we tie
all are signal generators to a 10 MHz GPS disciplined rubidium standard
which is said not to need calibration but still needs verification. So can
we only send our rubidium reference for verification once a year but extend
our signal generators out to 3 years?

Any thoughts?

Thomas

Most of our equipment is calibrated yearly. Most of our equip comes with an
initial calibration report and suggests the calibration cycle. ISO does not
specify a cycle, but if you specify a specific cycle they expect you to
adhere to it.

 

[Jim Yanik]

Most of our equipment is calibrated yearly. Most of our equip comes
with an initial calibration report and suggests the calibration cycle.
ISO does not specify a cycle, but if you specify a specific cycle they
expect you to adhere to it.

Also,your ISO should track calibrations,and provide for shortening the cal
cycle if the item keeps having out-of-tolerance reports come back on it.

ISO is pretty much "you decide what you want,write it down as your ISO9xxx
procedure,and then follow it" but with "corrective action loops".

 

[Ken Smith]

I work for a small start up company, and we are trying to determine what we
can get away with for the period in which we calibrate our production test
equipment. Does anyone know who should define the calibration cycle of test
equipment used in production? Is it the manufacturer of the test equipment,
is it a ISO definition, can it be self defined by QA and if so, I'm guessing

Take out a sheet of paper.

Write on it "we never calibrate our equipment and ship any old crap that
falls off the end of the production line". If now, you do as you say, you
are ISO. (A small exageration)

The real issue is the next one:

that some customers will complain if they notice a 5 year cal cycle on their
calibration certificate which we provide to them.

If you believe that the customers will let you away with longer than is
needed to make good product, go with your judgement. If the customer
wants a shorter cycle than is really needed go with theirs.

All ISO is about is doing what you've promice to do. Once you've honestly
figured out what is best, document what you do. You may need someone who
is expert in the field to make you the 1000 pounds of boiler plate that
goes with your few pages.


Also get some "calibration not required" stickers for the beepers they use
for checking the cables.

 

[electronic-eng.com]

Hi, I have worked for two start-up electronics companies and two large
multinationals as an electronic design engineer. In all cases it is
best to follow the manufacturers guidelines with respect to calibration
intervals. Although you may think they are using a short calibration
interval as a money making exercise, you should stick to it. Their
technicians are usually very helpful with questions like yours. When
your customers come to 'visit' (audit) your facility before letting you
supply them or design for them, they will want to ensure you are a
quality company. Any auditor worth his salt will check your calibration
schedule is in tune with the manufacturers recommendations, and if they
find you making short-cuts here, they will go looking for short-cuts
elsewhere, and if they find any, kiss bye-bye to that contract. It's a
simple as that. In a start-up it's good to try new things, but not in
this respect. I agree ISO is just 'do what you say you are doing'. In
summary, start-ups shouldn't give customers any excuse not to do
business with them.

Hope this helps!
www.electronic-eng.com

 

[Joseph2k]

I work for a small start up company, and we are trying to determine what
we can get away with for the period in which we calibrate our production
test equipment. Does anyone know who should define the calibration cycle
of test equipment used in production? Is it the manufacturer of the test
equipment, is it a ISO definition, can it be self defined by QA and if so,
I'm guessing that some customers will complain if they notice a 5 year cal
cycle on their calibration certificate which we provide to them.

So how is the best way to define a calibration cycle? For instance, we tie
all are signal generators to a 10 MHz GPS disciplined rubidium standard
which is said not to need calibration but still needs verification. So can
we only send our rubidium reference for verification once a year but
extend our signal generators out to 3 years?

Any thoughts?

Thomas

Noted other replies, all seem valid. Just the same:
1. Consider what causes drift / inaccuracy / unreliability of your product.
2. Consider what measures have already been taken in the design of your
product to counteract these problems including, self calibration
monitoring.
3. Consider in light of the previous two items how long it will take for
some stated percent of units to approach the limits of stated accuracy in
the proposed calibration cycle.
4. Consider the costs of calibration and the costs of units found to be out
of specified accuracy at the end of the calibration cycle. Much of this
will be reported to you in term of customer satisfaction.
5. Quantify all this as best you can, then you can make an informed decision
on how long the calibration cycle should be.

 

[Rich Grise]

Hi, I have worked for two start-up electronics companies and two large
multinationals as an electronic design engineer. In all cases it is best
to follow the manufacturers guidelines with respect to calibration
intervals. Although you may think they are using a short calibration
interval as a money making exercise, you should stick to it. Their
technicians are usually very helpful with questions like yours. When your
customers come to 'visit' (audit) your facility before letting you supply
them or design for them, they will want to ensure you are a quality
company. Any auditor worth his salt will check your calibration schedule
is in tune with the manufacturers recommendations, and if they find you
making short-cuts here, they will go looking for short-cuts elsewhere, and
if they find any, kiss bye-bye to that contract. It's a simple as that. In
a start-up it's good to try new things, but not in this respect. I agree
ISO is just 'do what you say you are doing'. In summary, start-ups
shouldn't give customers any excuse not to do business with them.

Hope this helps!
www.electronic-eng.com

Well, I wish you googlegroupies would learn how to quote context. It's
trivially easy - instead of clicking on the "Reply" link, click the "Show
Options" link, which opens up an options window - click _THAT_ "Reply"
link, and google will quote context for you.

So, back to the topic, I'd add the recommendations of whatever company
does your cal's for you, but if that's dramatically different from the
manufacturer's recommendations, I'd investigate the discrepancy, and of
course, leave a paper trail.

Good Luck!
Rich

 

[electronic-eng.com]

Well, I wish you googlegroupies would learn how to quote context. It's
trivially easy - instead of clicking on the "Reply" link, click the "Show
Options" link, which opens up an options window - click _THAT_ "Reply"
link, and google will quote context for you.

IMHO contextual replies take up too much space regurgitating text that
you just have to scroll through (and yes I see the irony behind this
comment itself being text you have to scroll through), if you are
familiar with the thread you should know what people are talking about.
It's a matter of style I guess, each to their own.

 

[electronic-eng.com]

Well, I wish you googlegroupies would learn how to quote context. It's

trivially easy - instead of clicking on the "Reply" link, click the "Show
Options" link, which opens up an options window - click _THAT_ "Reply"
link, and google will quote context for you.

IMHO contextual replies take up too much space regurgitating text that
you just have to scroll through (and yes I see the irony behind this
comment itself being text you have to scroll through), if you are
familiar with the thread you should know what people are talking about.
It's a matter of style I guess, each to their own.

Alan
www.electronic-eng.com

 

[Rich Grise]

IMHO contextual replies take up too much space regurgitating text that you
just have to scroll through (and yes I see the irony behind this comment
itself being text you have to scroll through), if you are familiar with
the thread you should know what people are talking about. It's a matter of
style I guess, each to their own.

Alan
www.electronic-eng.com

OK.

Then I guess we'll just quit bothering to reply to your googlegroupie
replies since they "take up too much space"

Good-by.

 

[John Fields]

IMHO contextual replies take up too much space regurgitating text that
you just have to scroll through (and yes I see the irony behind this
comment itself being text you have to scroll through), if you are
familiar with the thread you should know what people are talking about.
It's a matter of style I guess, each to their own.

 

[John Fields]

IMHO contextual replies take up too much space regurgitating text that
you just have to scroll through (and yes I see the irony behind this
comment itself being text you have to scroll through), if you are
familiar with the thread you should know what people are talking about.
It's a matter of style I guess, each to their own.

---
No, it isn't a matter of style, it's a matter of courtesy.

Assuming that everyone who is familiar with the thread doesn't need
context leaves out those who are only just coming into the thread,
without a clue, and don't want to wade through the previous 40 posts
and follow all of the meanderings of the thread before it got to the
place that they thought looked interesting enough to explore.

Just like bottom posting is generally preferred here, so the thread
flows more like a chronologically ordered narrative.

LOL, I see you decry contextual replies, yet _had_ to make one in
this instance in order for your post to be more readily understood.

Ironic, Indeed!

 

[electronic-eng.com]

---
No, it isn't a matter of style, it's a matter of courtesy.

Assuming that everyone who is familiar with the thread doesn't need
context leaves out those who are only just coming into the thread,
without a clue, and don't want to wade through the previous 40 posts
and follow all of the meanderings of the thread before it got to the
place that they thought looked interesting enough to explore.

Just like bottom posting is generally preferred here, so the thread
flows more like a chronologically ordered narrative.

LOL, I see you decry contextual replies, yet _had_ to make one in
this instance in order for your post to be more readily understood.

Ironic, Indeed!

ROFL, I think you missed the point of my 'learning' to use your
preferred method in my last post. If someone has a different preference
to you, then so be it.

Alan
www.electronic-eng.com

 

[Joseph2k]

Hi, I have worked for two start-up electronics companies and two large
multinationals as an electronic design engineer. In all cases it is
best to follow the manufacturers guidelines with respect to calibration
intervals. Although you may think they are using a short calibration
interval as a money making exercise, you should stick to it. Their
technicians are usually very helpful with questions like yours. When
your customers come to 'visit' (audit) your facility before letting you
supply them or design for them, they will want to ensure you are a
quality company. Any auditor worth his salt will check your calibration
schedule is in tune with the manufacturers recommendations, and if they
find you making short-cuts here, they will go looking for short-cuts
elsewhere, and if they find any, kiss bye-bye to that contract. It's a
simple as that. In a start-up it's good to try new things, but not in
this respect. I agree ISO is just 'do what you say you are doing'. In
summary, start-ups shouldn't give customers any excuse not to do
business with them.

Hope this helps!
www.electronic-eng.com

Alan, OP is not trying to evaluate the calibration cycle of test equipment
that they bought and use. OP is trying to determine omtimum calibration
cycle for some test equipment that they manufacture.

 

[Reg Edwards]

When new, calibrate every day for a week. If calibration doesn't shift
then calibrate weekly. If calibration doesn't shift outside limits
then calibrate monthly. When complete confidence is obtained calibrate
every 6 months. Much depends on usage. Maintain records with a
signature.

Send measurement standards to a standards laboratory for certification
every 12 months.

 

[Reg Edwards]

When new, calibrate every day for a week. If calibration doesn't shift
then calibrate weekly. If calibration doesn't shift outside limits
then calibrate monthly. When complete confidence is obtained calibrate
every 6 months. Much depends on usage. Maintain records with a
signature.

Send measurement standards to a standards laboratory for certification
every 12 months.

=======================================

Transport to and from the standards laboratory in vehicles with
ambulance-type suspension.

 

[electronic-eng.com]

Alan, OP is not trying to evaluate the calibration cycle of test equipment
that they bought and use. OP is trying to determine omtimum calibration
cycle for some test equipment that they manufacture.

The original posters language in stating their question is not 100%
clear, perhaps I have missunderstood the real question. Can he give us
more detail?

Alan
www.electronic-eng.com

 

[Al]

When new, calibrate every day for a week. If calibration doesn't shift
then calibrate weekly. If calibration doesn't shift outside limits
then calibrate monthly. When complete confidence is obtained calibrate
every 6 months. Much depends on usage. Maintain records with a
signature.

Send measurement standards to a standards laboratory for certification
every 12 months.

And make sure that the calibration is traceable to the national standard
of your country. After all, who calibrates the calibrators ;-)

Al

 

[Thomas Magma]

The original posters language in stating their question is not 100%
clear, perhaps I have missunderstood the real question. Can he give us
more detail?

Alan
www.electronic-eng.com

Sure. Our company manufactures test equipment that is tested and calibrated
by third party benchtop test equipment. For example, in the production of
our OEM test equipment, we use things like signal generators, spectrum and
network analyzers, power meters etc.. they all have to be calibrated. So we
are trying to determine (not the optimum but) the minimum requirement for a
calibration cycle that we can get away with. We currently do it every year,
but who is to say that we can't extend that out to 2 or 3 years or more.

Thomas

 

[Rich Grise]

Sure. Our company manufactures test equipment that is tested and
calibrated by third party benchtop test equipment. For example, in the
production of our OEM test equipment, we use things like signal
generators, spectrum and network analyzers, power meters etc.. they all
have to be calibrated. So we are trying to determine (not the optimum but)
the minimum requirement for a calibration cycle that we can get away with.
We currently do it every year, but who is to say that we can't extend that
out to 2 or 3 years or more.

Thomas

Well, you _do_ have a test piece, don't you? If it's still in cal after
one year, let it endure its test process for another year, and check it
again. And so on.

But I don't see what's wrong with a 1-year cal interval, if it's really
test equipment that needs certs.

Good Luck!
Rich