Barcode BWR adjustment

[Al Ferrari]

jlee, thank you for this valuable post.

Regarding the failed barcode needing a reprint, have you determined the specific cause of the failure yet?
Is it that in the file the BWR was in spec, but the printed barcode was not? In other words, was it definitely due to printing issues?
Was it printed by offset?
Was it printed in black? Was it on a white background?
Was the code on the first press unit, or one of the last units, that is, would press slur be the cause?
Was the failed code in the middle of the press sheet or out on the edge of a large press sheet?

I would be grateful if you would post the results of any investigation.

Al

 

[jlee]

jlee, thank you for this valuable post.

Regarding the failed barcode needing a reprint, have you determined the specific cause of the failure yet?
Is it that in the file the BWR was in spec, but the printed barcode was not? In other words, was it definitely due to printing issues?
Was it printed by offset?
Was it printed in black? Was it on a white background?
Was the code on the first press unit, or one of the last units, that is, would press slur be the cause?
Was the failed code in the middle of the press sheet or out on the edge of a large press sheet?

I would be grateful if you would post the results of any investigation.

Al

Al,

I have to say that the job I had on my desk was a flexo job. The code was printed in black on a white ink for a shrink sleeve. Slur wasn't the issue, it was incorrect BWR provided by a global prepress vendor who essentially applied a BWR meant for codes running in a ladder style which was opposite of press direction, it should have been run with a different BWR that is for a picket fence style code running in press direction.

But what I can tell you regarding offset is that I have seen the failures before due to excessive gain. I can recall one job in particular where a press approval from a brand manager dictated that we push density on black to make the background super dense, in effect it increased the gain on the code and we immediately got failures. But back to my last post if you have to verify to a standard (ISO,ANSI,GS1) than BWR can impact. GS1 publishes a document that explains all the verification "http://www.gs1.org/docs/barcodes/GS1_Bar_Code_Verification.pdf". This document defines the categories of criteria and specifications for the barcode grading. It also has a section explaining what could cause a barcode to fail. We've found that the "Modulation" and "Decodability" criteria are impacted by BWR and the worst part is that I can have a verification report that has "A" grades for everything but a fail in one of the categories dependant upon BWR which gives me an overall fail and automatic customer rejection. My report would tell me that I'm out of tolerance by 1/1000th of an inch and now I have to reprint the job even though I'm fully aware that any retail scanner would have no difficulty with the code.

We generally use 25 microns in BWR and have found little issue. Where I'm really lucky is that on the offset side we generally run only 2 substrates and both have been very successful with the 25 micron BWR. I have to admit I have seen instances where we have to increase to the 40 micron range on offset where customers may not run the barcode in process black (due to the fact that it's not in the job) but in the darkest spot colour. Considering that the spot colours don't gain the same way a process colour will, and usually the darkest spot colour the customer wants very dense it can result in excessive gain. We're also fortunate that we have multiple barcode verifiers in our plants that actually pull reports to tell us how much growth is in a barcode so if we run something and the barcode grew too much the report tells us how much and we can than extrapolate what we need to do to make it pass, make a new plate file for the colour run a plate and we're back on press in 30 minutes.

JL

 

[Al Ferrari]

jlee, your post is pure gold! Thank you.

Have you considered having verifier scanners at the press itself? Since the position of the codes on the press sheet layout changes from job to job, this may not be practical on the press delivery itself but could be done at the inspection table for pull sheets.

I am imagining a movable bar mounted on tracks or rails at the inspection table with several movable verifier scan heads mounted on this bar. The bar could then be easily rolled up ad down to cover the whole press sheet. The position of individual scan heads on the movable bar could be set for each job as part of the job set up, and for each pull sheet, the bar would be rolled up/down.

Although I just thought this up on the fly here, installations somewhat like this probably exist.

Al

 

[jlee]

jlee, your post is pure gold! Thank you.

Have you considered having verifier scanners at the press itself? Since the position of the codes on the press sheet layout changes from job to job, this may not be practical on the press delivery itself but could be done at the inspection table for pull sheets.

I am imagining a movable bar mounted on tracks or rails at the inspection table with several movable verifier scan heads mounted on this bar. The bar could then be easily rolled up ad down to cover the whole press sheet. The position of individual scan heads on the movable bar could be set for each job as part of the job set up, and for each pull sheet, the bar would be rolled up/down.

Although I just thought this up on the fly here, installations somewhat like this probably exist.

Al

Al,

The technology is available but really quite expensive also there is question as to whether or not camera verification is as accurate as a laser reader. The issue would be the number of cartons on a press sheet and to test this at press speeds, the cost is astronomical. As a reference point our TruCheck verifier which pretty much verifies any code symbology under the sun cost about $15K it has both a laser head and a camera head for 2D codes. Just imagine the cost if you had 32 cartons on a press sheet.

As for the whole camera thing, we have a customer that would verify barcodes on their filling line via camera. We printed a 2D code for a test and we actually couldn't get it to verify with a pass in our plant. The customer insisted that we send the test so they could try it on their verifiers. They ended up with a passing grade which made us question how that was possible. Upon further investigation, we realized that we could change the aperture on our camera and basically blur the capture of the code and we made it pass too! 2D codes have error correction built in and the software from the verifier applied this during the evaluation of the code, but when we gave it a crisp and clean image it detected other issues that made it fail. But since it worked on the customers line due to a blurry image, we could make the verification report pass by replicating those conditions. The product runs 5 times a year with absolutely no issues, makes you wonder about the validity of a 2D barcode verification.

JL

 

[Al Ferrari]

jlee,

I new my suggested contraption would be expensive due to the multiple heads. But my approach at least deals with the speed issue by limiting the scanning to just pull sheets instead of the press stream, and uses only as "few" heads as there are columns or rows of cartons on a press sheet. I don't have to tell you that the cost justification needs to be done against the saved reruns or those half hour press stops while an adjusted new plate gets made and mounted.

Al

[Edit 8-19-12] Actually my last statement is simply wrong since by the time my suggested contraption detects the problem on the first pull sheets, the plate remake costs have already been incurred.

 

[Al Ferrari]

jlee or any one else,

Are the barcode grading criteria used for codes in the Pharmaceutical industry more stringent than those used for other industries? Has this to do with the health related aspect of the products involved?

Al

 

[arkay_desai]

Hi,

Bar code grading is in all industry wherever barcodes are generating. Here is some tips for coloring the bar codes.

Altek Instruments -> BarcodeMan -> Barcodes: Color & Contrast

 

[jlee]

Al,

As Arkay stated, it doesn't matter about industry. Pharma cares a lot about the accuracy of the code numbers as we actually print more codes on Pharma packaging (usually in carton flap areas unseen to the consumer when the package is closed) which is usually used at the filling site to validate that the correct carton is being used for the product as it's one of the multilayered processes to prevent product mix. But at the same time this is also valuable in any food manufacturing to ensure product mix protection. We utilize the ANSI verification grade for all of our customers regardless of their industry. I would have to say that all the major food players also specify the grading in their packaging specifications, however I believe this is due to the fines associated with bad scans. I know that Gordo added a link regarding scanning laws, but those are for consumer protection and levied against retailers who basically have glitches in their UPC databases not the scannability (wow, I guess I just made up a new word) of the code.

I shouldn't be quoted on this because I don't know first-hand and my dollar amounts may be off but I understand that WalMart has some of the industries toughest fines. From what I'm told they have a 3 strike system where the first barcode scan failure is a $5K fine to the manufacturer, the second is $15K and the third is de listing of your product an no longer being sold at WalMart. Considering that some major players such as J&J, kraft or P&G derive a great percentage of sales just through WalMart they need to ensure that they have no scanning issues at checkout. I believe this has more to do with efficiency at their checkout considering that a scan failure results in time for the cashier to actually enter all 12-13 digits into the register by hand. I've also read that Costco is looking to make it mandatory for each panel on the box to have a barcode or they will not sell your product, they did a huge study about how long it took their cashiers to rotate and flip boxes to find the barcode. I can tell you that the brand managers and marketing folks I deal with are really upset about this due to the fact that the barcode will visually interrupt the designs they have if a code needs to be everywhere.

I hope that answers your question,

JL

 

[Al Ferrari]

arkay,

Thanks for the response, but the link you give: Altek Instruments -> BarcodeMan -> Barcodes: Color & Contrast

contains this paragraph:

"Infra red and far red scanners also have difficulty reading barcodes printed on thermal paper. These days most thermally printed barcodes use a 'thermal transfer' ribbon. This consists of a carbon black based pigment in a wax matrix. Thermal transfer barcodes usually have excellent contrast with all types of scanner."

This is very poorly written and thought out. The first and last sentences in that paragraph say exactly the opposite of each other!

I sent them a message to them pointing this out, but received an automatic response that they are no longer responding to new inquiries. So they are not likely to correct that.

The next time you want to offer that web page as resource, you should point this out.

Al

 

[Al Ferrari]

jlee,

Your response as usual is very informative. Thank you.

But the link posted by Arkay is problematic. Please see my response to his message.

Al

 

[arkay_desai]

Hi Ferrari,
Thanks for your info. I didn't gone through completely on this article.
How exactly you are printing barcode in thermal? By using images? or through any VDP software? If you are using images, barcode grading problem is may be because of image quality. also check with printing direction / orientation

 

[Al Ferrari]

Arkay,

I am not printing in thermal at all. I simply read your post and the link to educate myself. Except for that contradictory paragraph, I did learn several things from that link.

Thanks.

Al

 

[Al Ferrari]

I just received this response from the "Administrator" @ Altek Insruments Ltd, UK - BarcodeMan:

"You should read the section again- more carefully. The first sentence talks of 'thermal paper' the last sentence refers to 'thermal transfer ribbon'. These are two totally different 'thermal' technologies."

They are correct, of course. My bad. But But in the interest of clarity, those two technologies would be best discussed in separate paragraphs. I will write back to them with this same acknowledgement.

Al

 

[cindy313]

Hi Ferrari,
Thanks for your info. I didn't gone through completely on this article.
How exactly you are printing barcode in thermal? By using images? or through any VDP software? If you are using images, barcode grading problem is may be because of image quality. also check with printing direction / orientation

software is better to print