Spare Metal Detector Calibration
Hi,
I am stuck with the Metal Detector Dilemma for a while now :/
Can you please help me out?
We have a spare Metal Detector that we keep around and use it as a back-up in case ANY primary metal detector broke down. we have almost 12 MDs in our plant and they are all set with different limits and have different products going through.
Now this Spare MD does not have any calibration documents, and we were looking to calibrate it. The hardest question I face is on which limits should it be calibrated?
Can we calibrate it for the lower limits in all of the MDs we have, and then use the test kits to verify it before using it on any line?
If know you guys answered another question I had saying that we do not need to calibrate for different programs, can you please give me a reference to that in case this was challenged by the auditor?
Thanks alot!!! You are my saviors!
Hi,
I am stuck with the Metal Detector Dilemma for a while now :/
Can you please help me out?
We have a spare Metal Detector that we keep around and use it as a back-up in case ANY primary metal detector broke down. we have almost 12 MDs in our plant and they are all set with different limits and have different products going through.
Now this Spare MD does not have any calibration documents, and we were looking to calibrate it. The hardest question I face is on which limits should it be calibrated?
Can we calibrate it for the lower limits in all of the MDs we have, and then use the test kits to verify it before using it on any line?
If know you guys answered another question I had saying that we do not need to calibrate for different programs, can you please give me a reference to that in case this was challenged by the auditor?
Thanks alot!!! You are my saviors!
Hi Mariam,
Is there a particular Standard involved ?
Second question - What do you mean by "Calibration" ? = Sensitivity ?
See this Post -
https://www.ifsqn.co...rs/#entry105910
PS - if you are referring to sensitivity then the latter should be "optimised", eg -
We are BRC certified.
I meant the annual external calibration for the MDs. our program is set as to externally calibrated MDs & X-Rays by a service provider annually.
We are BRC certified.
I meant the annual external calibration for the MDs. our program is set as to externally calibrated MDs & X-Rays by a service provider annually.
Yes, but what do they specifically "calibrate" ???
BRC8 does not specifically mention "calibration" of MD however the Guidance comments that a "calibration" should at least cover elements in clause 4.10.3.3. This particularly relates to my query in Post2 involving "sensitivity".
hi Mariam,
You will probably, minimally, need to know the optimum sensitivity of yr spare MD.
This will then enable you to know which if any of the other units it can fully replace.
For example, if the sensitivity of spare MD for a particular product is equal to or better than all the other units then it can replace any of them for that product (assuming other functions like rejection mechanism are satisfactory).
Contrarily, if the sensitivity is poorer than any of the other units, it may still be able to replace it if the loss in detection capability. is considered acceptable.
Hope that makes sense. :smile:
We have a plant with 2 spares, they are routinely tested each day with all test pieces - and set at the lowest detection level, thus at any given time they can be put into service.
We have a plant with 2 spares, they are routinely tested each day with all test pieces - and set at the lowest detection level, thus at any given time they can be put into service.
I think you mean set at the MD's lowest achievable detection level. Typically varies with lots of things, eg type of product tested..
I have a query to add along with this one. How about getting the spare MD calibrated for the range of limits that is used at the site? Won't it be helpful that way?
hi Mariam,
You will probably, minimally, need to know the optimum sensitivity of yr spare MD.
This will then enable you to know which if any of the other units it can fully replace.
For example, if the sensitivity of spare MD for a particular product is equal to or better than all the other units then it can replace any of them for that product (assuming other functions like rejection mechanism are satisfactory).
Contrarily, if the sensitivity is poorer than any of the other units, it may still be able to replace it if the loss in detection capability. is considered acceptable.
Hope that makes sense. :smile:
Hi Charles,
Yes that makes perfect sense. I talked to the Calibration technician and he explained that we cannot just use the MD to replace any other MD in the plant. The aperture size, the moisture content and type & packaging of products that get through the MD are all factors that affect sensitivity.
The plan is to make a list of products that can physically go through the MD, then have another visit for him to check if the MD will be able to work with detecting MD in those products with good sensitivity, then we could assign that spare MD to be a replacement to the MD where the tested products usually runs.
As for the greater sensitivity being enough to run lower sensitivity products, he also said that if we are running different products on the same line with different limits, it is better to get it calibrated for the 2 different programs, not just the greater one.
Tbh, if he is coming in to calibrate MDs anyway, we might as well get everything calibrated and avoid any confusion that might happen.
We have a plant with 2 spares, they are routinely tested each day with all test pieces - and set at the lowest detection level, thus at any given time they can be put into service.
We actually do that to another MD in another plant, but that one is the same make & model of the MDs it replaces, and the products that runs through are the same.
The one I was inquiring about was confusing because in that Plant we have multiple products, with different characteristics, so I wanted to make sure that we are not compromising the safety of the products because we wanted to save some extra calibrations.
Thanks !
I have a query to add along with this one. How about getting the spare MD calibrated for the range of limits that is used at the site? Won't it be helpful that way?
Hi,
I am not sure what you mean, if you mean range of limits as in different programs with different limits, then yes, That's what I was thinking.
But when I double checked with the calibration technician, he set that we need first to make sure that the MD is capable of detecting foreign material (Metal) in these conditions (type of products, moisture content, packaging...etc) before just calibrating it to different limits.
Can a spare metal detector be calibrated and configured to run?
It's possible but how well the unit will perform the moment you put it in the line will depend on a variety of factors. If you can, I would like to know the answers to the following questions:
Are all of your metal detectors the same make and model?
Does each line run at approximately the same speed?
Are the aperture dimensions the same for all of your metal detectors?
What is the make and model of your spare unit?
What type of product are you inspecting on the lines?
What are your test standard sizes including the grade of stainless if stainless steel is included in your test standards?
What frequency or frequencies do your metal detectors operate at?
These questions are important to know the answer to because they all will play a roll in determining what your metal detectors are capable of and how they compare to one another.
For example, if you run a very conductive wet product on all of your lines and all of those metal detectors are running at 100 kHz, chances are of the spare unit you have is running at 300 kHz and even worse has a smaller aperture too, you will be fighting false positives all the time unless of course your test standards are very large and create a much greater signal than the product being inspected.