A global supplier to the packaging industry recently received a quality alert from an important building materials customer: their barcodes were failing in US home improvement stores. The UPC barcodes were not working on the packaging for certain products but working fine on others. What was the problem?
A Deepening Mystery
Branding and product differences require different products to be packaged in different material types. Some products were packaged in specially pigmented paper, others in bare kraft. Some barcodes were printed over a white slug, others directly onto the substrate. Product differences necessitated graphics design differences on various product types. Over time this led to variations in the sizes of UPC’s used, some as small as 120%–quite small for the flexo process being used.
Verification testing revealed that the failing UPC’s were excessively gained, some using more than the entire plus-side tolerance for bar width. Barcode failures were not linked to UPC magnification as one might have suspected. Some smaller symbols were performing well, some larger symbols were failing. Neither were failures related to substrates, although bare kraft had the usual low symbol contrast problems.
The Mystery Unravels
The obvious solution was to adjust the bar width reduction (BWR) in the plate. The plates were insufficiently compensated for gain–why? The mystery began to unravel. The supplier and plate maker could not remember having any discussions about bar width reduction. Furthermore, the supplier used several plate makers including one offshore. None of the vendors had ever been told—and none of them had ever asked—about bar width reduction.
Who is Responsible?
Everybody in this story has some responsibility. The vendor qualification process should include the supplier providing all vendors with a barcode quality policy statement supported by a barcode quality document. But best practices also apply to vendors who, if not told, should ask about how the supplier’s barcodes should be prepared including imposing the proper amount of BWR. But at the end of the day, all the shoulds and oughts do not really define who is responsible; liability does. The supplier is liable for the performance of the package, of which the barcode is an essential part, and they also bear responsibility for the performance of their vendors and subcontractors. Excellent communications make these important relationships viable. Clearly expressed and up-to-date expectations make good long-term business.
Barcode quality procedure includes not only what is expected as a minimally acceptable barcode grade but how it must be tested and reported. Only an ISO compliant verifier is acceptable and it must be user-calibrated at least monthly—weekly is better and daily is not too much for high-volume production.
You Get What you Enforce
The best of intentions do not manage risk. Enforcement does. Even when barcode quality policy and procedures are well communicated, it is wise to build in practices that make it easy to check that things are going as required. Including a verification report with each job’s packing slip or work order documents that the verifier was used, the grade achieved and the last calibration date.
