Sticking to the Right Formula: How Glue Rolls Can Affect Your Bottom Line
09 July 2018
Properly maintaining your corrugated glue rolls is extremely important, as ones that are out of round or not parallel can be expensive. This is the case because the machine will consume more adhesive during the process, leading to additional costs. If a roll is out of round, every revolution will change the gap with the metering roll. As a result the thickness of the adhesive film will change as the roll turns.
Moreover, the gap between the lower corrugated roll will also change with every revolution, which also negatively affects adhesive application. In order to compensate the differing levels of adhesive, the operator will usually have to adjust the metering gap to ensure that there is enough adhesive for the thinnest parts of the rolls.
To calculate how much additional cost defective rolls actually run, one simply has to look at the TIR (total indicated runout) - the ratio or distance that the roll is out of parallel - as this will be proportional to the overall increase in adhesive consumption.
For instance, a glue system in proper working condition will apply adhesive on the roll at an average of around 0.007” thick. However, if it has a TIR of 0.006”, then the film thickness may increase by up to 2/3 of that gap (0.04”) if not adjusted. As a result the average thickness of the adhesive will not be stable and may range from 0.007”- 0.011”. This will effectively result in a 20% increase in adhesive consumption; therefore, according to an article by the ACCA, as a rule of thumb every 0.01” increase in TIR will result in an increase in adhesive consumption of almost 3.5%. Likewise, the degree to which the metering gap is out of parallel will also reflect a 2/3 change in film thickness, therefore causing a corresponding higher adhesive consumption.
With today’s modern technology and advanced machinery able to do high speed runs, producers can easily create large amounts of board; however, failure to maintain each element of your system will in turn result in the consumption of high amounts of adhesive. Out-of-round or out-of-parallel rolls will increase this amount even more, potentially adding significant extra costs. Daily checks of your machines are therefore imperative to ensure board quality and maintain adhesive consumption.
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