The greatest insight I can share with you to date is this; “There is no rule book for the task we are undertaking” Without exception, upon trialling any new material it must first be exhaustively tested before it can be fully understood. All new materials bring their own individualities and our role is largely to understand how trm can make the most of them. The good news is that trm are ahead of the rest in dedicating time and resources to this, giving us a technical edge.

In recent months several new opportunities have been explored using alternative papers. Advancing technologies in the paper industry along with improved performance from our corrugator now allow us to use lighter weight papers.

The most recent paper successfully trialled is a light weight dual purpose paper. This is presently being used as a substitute for our medium weight waste based fluting but could also be used a Test liner.

Testing was conducted initially on the board itself then on 6 pre defined case sizes. Testing on the board revealed a strength loss compared to board using medium weight fluting which is not unusual. Testing on the cases was performed in two sections, medium sized cases with a perimeter of 1350mm and small cases with a perimeter of 676mm, with the following results:

When using the light weight paper in medium size cases there is a small gain in performance (about 5%) however, when testing the small cases there was an unexpected loss (about 6%). Considerable thought, research and consultation were required to determine the cause of this loss. Understanding why the paper performed differently when used to manufacture smaller cases is vital to its use and others similar to it.

The reason for this drop lies in the construction of multi purpose papers. In order to give them both the strength and finish required they have starch added. This starch does, however, also result in increased brittleness. When small cases are compressed this brittleness leads to reduced elasticity (when compared to waste based fluting) and therefore an increased propensity to “snap”. Larger cases have a greater area over which to spread the force at which point the increased strength sees the improved performance shown in the graph.

Ongoing testing on all our grades is allowing the compilation of a comprehensive bank of ECT compression data. The department is working towards data on all grades and I will include here an update each issue on our top performing paper combinations.

In the coming month continuing with the learning process regarding papers and their process performance, we intend to produce a trial utilising Kraft liner as a fluting medium. Using data already collected it will be possible to judge its performance and suitability against standard grades whilst also assessing its performance in the corrugating process. More on this project in next issues update.