How precisely a print product is folded and the extent to which a folding machine delivers consistently high folding quality, even at very high speeds, depends to a significant degree on the design of the folding rollers. At its Ludwigsburg site, Heidelberger Druckmaschinen AG (Heidelberg) develops and manufactures its highly productive Stahlfolder folding machines. In recent years, the company has invested part of its research resources in the further development of its folding rollers.

Users of Stahlfolder folding technology currently need to choose between folding rollers equipped with rings made from either soft or hard PU (polyurethane). These are called ‘Extra Grip’ rings on the market. The two materials have very distinct characteristics. The substrates to be processed and their surface structure determine whether the softer and more elastic PU or the harder one is more appropriate, so the customer is faced with a decision.

Heidelberg says that its development engineers, therefore, set themselves the challenge of combining the benefits of soft PU and hard PU rings in a single material. The result is being presented to the public for the first time during ‘IT’S SHOWTIME’ – a digital customer event. According to Heidelberg, its in-depth knowledge of the interactions between different types of paper, various materials, and the geometrical and physical conditions within a folding system has allowed Heidelberg to make great progress in developing new materials.

The function of the new plastic ring is to transfer the power generated by precise folding machine engineering as gently and accurately as possible to any type of paper and to ensure the best possible processing quality – from the first parallel fold in the buckle plate folding unit to the fully folded end product. The newly designed Perfect Grip plastic now needs to prove its unique characteristics in initial practical tests.

“Our aim in developing Perfect Grip is to combine the best of both worlds,” says Jörg Dähnhardt, head of product management postpress at Heidelberg. “If we’re successful, it will be another major step forward for folding rollers and will keep our customers happy by further improving the versatility and cost-efficiency of Stahlfolder folding systems.”