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FLEXO Magazine : Dec 09
8 FLEXO DECEMBER 2009 www.flexography.org FTA's Flexo Quality Consortium (FQC) has embarked on a study to determine the repeatability and reproduc- ibility (R&R) of current anilox measurement devices. Predictable and repeatable print outcomes are essential to the success of a flexographic printing operation. One of the numerous variables that needs to be controlled is the wet ink film thickness. The ink film thickness is affected largely by the anilox volume (BCM/in2). Generally, the higher the anilox line screen, the smaller the volume of roll, and vice versa. "So what?" you may say. "I have my '2.0 BCM/in2' anilox roll. What's the problem?" The challenge, simply put, is one manufacturer's "2.0 BCM/in2" anilox roll might not necessarily carry the same ink volume in a square inch as another manu- facturer's "2.0 BCM/in2" roll as the result of using a different " ruler" or measurement device. At present, there is no ANSI standard for anilox rolls measurements. The FQC project, as such, will determine the capabilities of current measurement devices and techniques along with potentially determining calibrations between instruments. Led by Dan Reilly (Flint Group) and Jean Jackson (Praxair Surface Technologies Inc.), the FQC project committee aims to deter- mine measurement equipment and methods used at anilox roll manufacturer sites, as well as those used in-house printer/ converters and by roll manufacturers during field audits. The team includes printers, anilox roll manufacturers, instrument manufacturers, ink suppliers and other industry partners. The group will design a gauge R&R (repeatability and reproduc- ibility) study to test equipment and operator interface at a chosen neutral site. Once the data is compiled and analyzed, the FQC committee will report the results of the study and determine next steps if need along with updating FIRST 4.0. The goal of the FQC project is not to pick a system or define ink laydown. Instead, it is a gauge R&R study. The instrument's " repeatability" determines the variability of the instruments measurements taken by a single operator or instrument under the same conditions. The instrument's " reproducibility" determines the variability induced when different operators use the device on the same conditions. The committee intends to determine these capabilities and tolerances of the devices and not select an instrument. Based on the results, the anilox roll manufacturers and printers can determine the instrument or device that fits the need and op- erating environment. Many times, a printer/converter will have its rolls audited in a press where it is not possible to measure with some larger instruments used while manufacturing the roll, so alternate devices or tools are used. They also might find during an audit that a roll has gained or lost some vol- ume though there may be no difference in that particular roll's performance, as the loss or gain is within the measuring toler- ance of the device used. Similarly, a 900lpi 2.5 BCM/in2 roll from one company will not necessarily perform the same as a 2.5 BCM/in2 from its competitor as they used different instru- ments or techniques and a correlation might be necessary between the instruments and suppliers products. In a nutshell, the project aims to compare apples to apples. In a sense, one company may be using a yard stick and the other is using a meter stick. The FQC seeks to understand the reli- ability and repeatability between those the measuring devices, and the variables and tolerances that affect the anilox volume measurements. The project results should allow tolerances to be established on anilox volume measurements and instruments. It may also facilitate the creation of optimized procedures for each instrument to improve repeatability of measurements and calibration. Given the outcome, the FQC committee could then investigate a possible follow-up study (if necessary) that would relate to print results or ink film laydown. Your Ruler or Mine? FQC Initiates Anilox Volume Measurement Gauge Study • One manufacturer 's 2.0 BCM/in2 anilox roll might not necessarily deliver the same ink film thickness as another 's 2.0 BCM/in2 anilox roll. • The goal of the FQC project is to conduct a gauge R&R study on the repeatability and reproducibility of current anilox measurement devices and techniques used during manufacturing and pressroom QC. • Most of the major anilox roll manufacturers and instrument suppliers have pledged their support. • Looking for consistent color, predictable print results, press productivity? Anilox roll volume measurements that are repeatable and reliable are critical. I test the reliability of measurement devices. Photos courtesy Pamarco Global Graphics. FTA TODAY
Sustainable EOY 2009