SchäferRolls GmbH

SchäferRolls cover H.impress. Up to 15 °C lower heat build-up during the embossing process at Lucart SpA in Diecimo, Italy

The processes involved in tissue converting make a significant contribution to the end product’s key attributes - attributes customers might see as a sign of high quality.

Author: Ing. Federico Barsanti, SchäferRolls

Ing. Federico Barsanti, SchäferRolls
Ing. Federico Barsanti, SchäferRolls

At high machine speeds, the tissue does not have much time to be embossed while located in the roll nip. As a result, the embossing rolls do not have much time to work their magic and achieve first-class embossing quality for the complete tissue web. Add to that the increasing complexity of embossing patterns, with different depths of micro and macro embossing and it’s clear that embossing back-up roll covers have their work cut out of them.

To meet these high demands SchäferRolls is proud to introduce the results of the last born: H.impress, an embossing roll cover which increases the performance in the most severe conditions (cover image). H.impress is a mix of special proprietary materials designed with particular attention to wear, elasticity and resilience properties of the cover material.
The new cover improves physical and mechanical material properties by far. In combination with an improved bonding technology it performs reliably in the long run.

Roll systems by SchäferRolls – precision all round

Fig. 2: H.impress, a multi-layer cover design

The new bonding technology developed for H.impress is based on a multiple layer technology (Fig. 2) that SchäferRolls has been applying for several decades with success in paper and tissue industry. The first layer is a hard material with high e-modulus to safely bond it with roll core. Between this first layer and the functional layer SchäferRolls applies two interleafing layers to progressively pass e-modulus from the core to the functional layer. The materials are media and ozone resistant mixtures against aging to keep the mechanical properties at a stable level in the long run even with temperatures up to 90 °C. The new functional layer, also a new mixture of media and ozone resistance rubbers, offers excellent resilience properties and very low compression set while reducing the internal heat generation to up to 15 °C compared to the best materials currently found in the market (Fig. 3).

Fig. 3: Properties H.impress for embossing back-up rolls

Up to 15 °C reduced heat generation at Lucart SpA in Diecimo, Italy

In autumn 2019 Mr. Graziano Solignani, maintenance manager at Lucart Diecimo, involved SchäferRolls’ expertise to analyze converting lines L216 and L220 where all roll covers from competition suffered a heat generation up to 70 °C and an uneven temperature distribution that caused frequent bearing failure on line L216 (micro position) and frequent cover delaminations on line L220 (décor position). It was the perfect environment for H.impress! In January 2020 SchäferRolls’ first roll with the cover H.impress was installed on line 220 and immediately showed an important benefit: the heat generation was much lower (56 °C) while the roll’s temperature profile remained stable (Fig. 4). These temperature results were soon confirmed also on line L220 where H.impress was able to reduce the heat generation for hysteresis by 10 to 15 °C lower than the best materials previously in operation. As a result the customer had no more bearings failure on line L216 (four suffered in the year 2019) and no more cover delaminations on line L220. Mr. Fabio Paoli, converting engineer at Lucart Diecimo confirms: “We are very satisfied of SchäferRolls products and their support to solve our problem. The roll covers perform excellently and allow our machines to run safely and according to plan. The paper quality obtained at maximum machines speed remains great and therefore we decided to exclusively rely on SchäferRolls covers in all our key positions”. H.impress proved to be a specialist for the embossing of tissue products offering excellent resilience properties and very low compression set. The low heat build-up and the increased mechanical resistance allow all machines to run reliably and according to plan while maintaining a consistently high embossing quality. H.impress can be used for micro and macro embossing and is thus an ideal all-round cover for premium tissue products.

Fig. 4: Stable temperature profile

It’s the rolls that make the paper. Roll covers for paper, tissue and board

SchäferRolls GmbH & Co. KG, based in Renningen, Germany, was established in 1946. With by now over 300 employees worldwide, the company manufactures technologically sophisticated and high-performance roll systems and roll covers for all industries, particularly for the paper, foil, textile, printing, furniture, packaging and metal industry, as well as for machinery and plant engineering. Production facilities are located at Renningen (Germany), Brnik (Slovenia) as well as at Farmington, NH and Covington, VA (USA) with a total production area of more than 32,000 m².

 

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