How long do your calibrations take?

[Jim Davey]

This is a question I would like to put to the wider audience you get on an international forum. So here it is, for those of you that have calibrations done, how long on average does the engineer spend calibrating (not servicing) and what equipment do you notice he does his tests with. Specifically, do you get a chap turn up with a reasonable sized box (load bank) with half a dozen switches on it and hook it up to your sets?

 

[madkayaker]

What type of equipment? I have test kit done periodically (not annual mostly when I have a job coming off that needs calibration paperwork never had kit that has needed adjustment) fixed wiring kit is done while I drink coffee at trade counter calibration day, pat tester was done in a couple of days and sent back to me.

 

[Jim Davey]

What I meant was the welding machine calibration, I should've been more specific EN 50504:2008.

 

[madkayaker]

I see. Can't help you there

 

[Welderpaul]

We had three Lorch Mig sets calibrated to BS 50504 about three weeks ago. He turned up with a Kemppi load bank with a load of switches on the front. The guts of it glowed red when it was on.
I wasn't paying much attention to him to be honest, but i'd say he took 15-20 minutes a set including scrawling out the results on his pad and stickering up the machines.

 

[madkayaker]

Looks like a bunch of resistors designed to simulate sat loads that are then compared to machine read out. I do simlor to generator sets

 

[Welderpaul]

He had a clamp meter i think, and the earth clamped onto the contact tip at one point i noticed.

 

[madkayaker]

Presume flow gauge etc has to be checked as well.

 

[Jim Davey]

T

Presume flow gauge etc has to be checked as well.

That doesn't fall within the scope of the test as far as I'm aware.

 

[Jim Davey]

Looks like a bunch of resistors designed to simulate sat loads that are then compared to machine read out. I do simlor to generator sets

Yep, here's the one I use in the shop and out on site.

 

[Welderpaul]

Very similar if not identical to the one they used, although theirs was a Kemppi.

We needed to have a test cert for our gauges for 1090, so BOC kindly offered their services to come in and do it.

 

[Wedg1e]

I do calibration of Mag Particle Inspection machines, whose principle of operation is near-identical to a welding set (huge transformer developing loads of secondary current but at very low voltages (2-4V on most machines at up to 6000A) so I figured the test loads (shunts) I use for them would work on welding sets but when I tried it, the welder went straight to max output irrespective of the switch setting.
I've done it the cheating way before: fire up an arc and have someone read the clamp meter on the return lead, compare that to the meter on the welding set, job bodged

 

[Wedg1e]

Yep, here's the one I use in the shop and out on site.

View attachment 41827

...so who calibrates your test loads?
We have our MPI ones checked every 5 years but then they are just huge lumps of copper, not much can change over time.

 

[Robotstar5]

I did ask about the calibration of robot welders as our weld techs happily dialled in 150A on the parameters with no means of verifying it was producing 150A, as it does not seem to be covered by TS16949 we never had our weldsets checked/calibrated.

 

[madkayaker]

Test load I use does 1mW at 400v! It's used less to calibrate read out of generator (as long as it's close) more to check set will give required output.

 

[Jim Davey]

...so who calibrates your test loads?
We have our MPI ones checked every 5 years but then they are just huge lumps of copper, not much can change over time.

It doesn't need a test, my meters do but the load bank just has to be able to sustain the current passing through it without damage. I do have to have clamp meter, voltmeter, tachometer and thermometer calibrated annually though. I think it takes about 15 calibrations to get back into profit after paying for that little lot.

 

[Robotstar5]

I do have to have clamp meter, voltmeter, tachometer and thermometer calibrated annually though. I think it takes about 15 calibrations to get back into profit after paying for that little lot.

It's the same for sparkies, have to have an MFT (multi function tester) costing £400 upwards plus calibration, then folks moan about the rates you have to charge!

 

[madkayaker]

It's the same for sparkies, have to have an MFT (multi function tester) costing £400 upwards plus calibration, then folks moan about the rates you have to charge!

Theats before part p fees

 

[Robotstar5]

Theats before part p fees

Don't get me started

 

[Jim Davey]

The reason I was asking about how long on average it takes and what the engineer brings to carry out the test is that lately I've been under quoted drastically by firms coming in and doing calibrations in some cases 5-10 minutes or less. The amount of times I hear "Oh they're great, they come into the welding bay, measure a few volts on the machine with a voltmeter, ask me to do a quick weld while they measure the arc with a current clamp, not down a few readings then they're off to the next one, brilliant!"

These 'awesome' calibration engineers can get through 60 'calibrations' a day, that's big money at £20 a pop for 5 minutes work. I call them calibrations but according to the European standard there's a lot more to doing a calibration than that.
The problem I face is that once a buyer has been given a price of £20 a machine to calibrate it, and they believe it can be done in around 5 minutes flat, it's a very hard sell to convince him the going rate for a skilled engineer to do a proper job is more like £50 and an hours work per machine on average. Ok, some welders are a peach to calibrate, an others are a swine but it probably averages out to maybe 40 mins each once you're under way and 10-15 mins of admin/paperwork filling out the certs back at base.
With this in mind I was thinking about drawing up a checklist for buyers/quality managers to ask their calibration service providers so they can satisfy themselves that they are getting exactly what they should be. Better still, anyone seriously considering commissioning calibration work should buy a copy of EN50504:2008 and read it for themselves to see what's required before parting with their hard earned cash. Unfortunately lots of people don't seem too worried and all too often I hear "I just need a piece of paper that says my kits ok, and that's all I'm interested in thanks."