“Do I need to verify my UID labels?”
I get asked this question all the time by DoD contractors who have to comply with MIL-STD-130. The answer to the question is “Yes!” – the standard clearly states that UID marks need to be verified so there is no question that you should do so.
According to MIL-STD-130, the contractor has a choice of verifying every label, or instigating a military approved statistical sampling program.
The problem here is that verifying UID labels can be time consuming and the equipment needed to do so is somewhat expensive. Combine this with the fact that the Datamatrix code used for UID marking is very robust in the first place has caused a lot of contractors to take a chance and not put into place a verification process.
This can lead to problems – I got a call late in the afternoon the other day from one of the large defense companies. They were receiving UID items from one of their sub-contractors and the labels failed to scan when read with their barcode scanner. This was causing the prime contractor a huge problem because it was holding up a large shipment for a contract.
The sub-contractor pointed out that the barcode scanned just fine at their facility.
You should be able to see the problem here – both parties were using barcode scanners (not verifiers) to check the UID barcodes.
When I got the chance to look at these labels and check them on our Microscan verifier, it was immediately obvious what the problem was.
The sub-contractor had left a space within the part number in the barcode. This isn’t allowed for UID labeling where the only allowed characters are 0-9, A-Z (only uppercase) and – (dash) and / (slash). (To be fair there is an exception to this, when Text Element Identifier are being used, but that’s for another day).
So our friend, the subcontractor, with only a simple scanner to read the barcode was completely unaware that he was in fact printing non-compliant labels and shipping them to his customer.
When the products arrived at the prime contractors facility, the labels were scanned and would not return the correct data format. At this location, a more sophisticated type of scanner is used and I believe it is programmed with a script that performs certain tasks when a UID barcode is read. Because the label contained a non-conforming barcode, the script would not execute and incorrect data was returned.
For any business, preventing a client from being able to use your products is not a good idea. The DoD put the verification rule into MIL-STD-130 to ensure that items being introduced into the supply chain contain the correct data and meet the quality guidelines to ensure that the UID marks can read at every step along the way.
So sure, you can save time and money by avoiding the verification step (if your DCMA QAR lets you get away with it). There is however a good chance that something will go wrong at some point and it might be a very expensive mistake.
If you are producing UID labels how do you handle the verification? Are you verifying every label? Some of them? Hoping for the best?
Call me at 603-598-1553 x237 to make sure you don’t make any big mistakes! We provide verifiers from both Cognex & Microscan.