Barcode Quality Procedures: The Map to Barcode Risk Management
Barcodes that don’t work right can be a liability. Managing that risk begins with a well conceived, diligently executed barcode quality procedures document. Yes, a document, a step-by-step standard operating procedure that is integrated into the corporate culture: it expresses a common goal, known and pursued by all.
Like any rigorous procedure, barcode quality begins at the beginning—that is to say, at the design stage. Believing that it eliminates potential variables, the barcode design file is sometimes supplied to the contract printer by the customer—often the brand owner. If the design file is not made to the printer’s process, this well-intended practice can be a serious misstep, causing rather than averting barcode quality problems. An example of this is a file that imposes a standard amount of compensation for print gain: litho printing will require less compensation than flexo printing. Step one of a barcode quality procedure is to make sure the barcode design file is optimized to the printer’s specification for bar width reduction and imaging device resolution (DPI).
Barcode quality used to mean just print quality, but today it also includes data structure: are the encoded characters presented in the correct sequence and prefixed with the correct Application Identifiers (AI)? At the same time the barcode design file is created, the barcode should be structurally validated. Manually inspecting each AI and its corresponding field of data is a laborious, error-prone method for doing this. There are portable data terminals with on-board scanners that perform barcode structural analysis—you can view one such device here. These devices are often used to validate a barcode on a press proof.
While pre-press operations are not inexpensive, the cost of pre-press mistakes pale in comparison to on-press errors and barcode mistakes detected in post-production inspection. Education is expensive but it takes less time to recover from a barcode mistake detected and rectified in pre-press than after the money is spent on ink, substrate and press time.
On-press operations should confirm and tweak the controls that assure high quality barcodes are being produced. This is neither the time nor place to discover the unexpected. Surprises are most effectively controlled by good record-keeping. Which inks work best with which substrates? What speed and pressure settings are best when printing barcodes? Is the barcode oriented to direction of travel? Are the barcodes across the web testing and grading the same or nearly so?
Once on press, barcode quality procedures should focus on spot-checking the printed barcodes according to a set schedule, whether that be based on number of impressions or time. Initial verification should confirm that the results are as expected; monitoring and tweaking may be required to achieve the target ANSI or ISO grade. Over time, initial grades may drift from the target; that is the point of spot checking over the course of the print run. Theoretically it is possible to plot the progression of a changing ISO parameter in order to anticipate when the threshold of failure will be reached.
The idea is to avoid ever reaching that threshold by making periodic adjustments as the print run proceeds. An ISO compliant, calibrated verifier gives you the situation awareness required to see those gradual parameter changes—and the ability to see the immediate impact of making the right adjustments to bring the process back into alignment.
Those migrations and the adjustments that correct them should be a part of the production history, appended to the verification results and retained samples of the printed output.