PR Rolls and its partners successfully carried out the rebuildind of an MG cylinder for Lenk Paper GmbH.

The high level of expertise and excellent cooperation between PR Rolls and its partners enabled the successful rebuilding of the MG cylinder for Lenk Paper GmbH. PR Rolls also customized a completely new coating specifically for this project, which the company expects to deliver strong results in the future as well. In the following interview Lenk Paper explains the background, the scope of services and the results achieved in this challenging project.

Please give us a brief description of the service required by Lenk Paper GmbH in Kappelrodeck:

The scope of service awarded to PR Rolls corresponded to the major refurbishment of the PM4 MG cast iron cylinder (Voith built in 1960) with a diameter of 4,000 mm and a cylinder width of 3,700 mm. A specified criterion for the production of fine paper qualities such as Protection Paper, Medical Paper, Interleaving Paper, Releaseliner was the basis weight range of 16 -90 g/m².

What scope of services did PR Rolls realize in this project?

Initially, this was an extensive MG cylinder inspection, which was carried out in cooperation with PANZER Engineering in advance of the service to record the current situation in detail. The service itself was then realized in the period from January 3 to 10, 2025 - in day and night shifts.

The scope of service can be described as follows:

• the pre-grinding
• necessary spot-repairs
• the coating with the TecnoCorr quality, taking into account extensive edge repairs on the driver and drive side
• then the grinding under consideration of a defined crowning
• followed by the coating with TecnoDiamond quality with a final layer after diamond belt grinding of a defined crowning. The coating hardness is 1,200 +/-100HV.

What has been Lenk Paper GmbH’s experience with the PR Rolls service, and what benefits have resulted from the measures taken by PR Rolls?

• Right from the start of the project, PR Rolls also provided advice on all the technological aspects that needed to be considered when switching from an MG cast surface to a future hard-metallized surface. 

• In this regard - in cooperation with PM Services + Doctoring GmbH and Lantier Solutions Inside - all necessary modifications to the two doctoring systems in use were also determined to ensure optimum doctoring of the MG cylinder in the future. The implementation was then successfully carried out in two steps, which ultimately also included the installation of 2 Lantier Extraflex double hose holders to ensure optimum profiling and simplified maintenance.
   
• After the blade holder adjustment by Lantier using the NEURLAN measuring system, the line load distribution was also determined, and a new force/pressure diagram was created based on this.
   
• The service work was completed on time on January 10, 2025 - exactly as planned - and from the first reel, we achieved a paper quality with an excellent and uniform surface quality (e.g. gloss/smoothness).  Even in the critical grammage range of 16 - 19 g/m², the paper web now has very good release properties from the hard-metallized surface of the TecnoDiamond coating since the measure was implemented.
   
• Since the PR Rolls service was carried out, the PM4 is once again able to map the maximum web width on the MG cylinder, which was one of the main objectives of this project.

The cooperation with PR Rolls and the other partners involved was extremely professional and efficient. Thanks to the comprehensive advice and precise implementation of the services, we have not only been able to overcome the technical challenges, but also to improve the quality of our products. The successful rebuilding of the MG cylinder has enabled us to produce the desired fine paper qualities with a uniform surface and to utilize the maximum paper web width.

We would like to thank PR Rolls for their professional support and look forward to future projects.

Jani Westerlund, CEO of PR Rolls Oy: The equipment we have developed, combined with careful pre-design and skilled personnel, enabled a successful project. We have customized a completely new coating for this job, from which we expect a lot in the future. The machine's drivability improves because, thanks to the coating now introduced to the market, the doctoring can be done at lower pressure.“

Careful pre-planning, skilled personnel, and good cooperation between all parties made the successful project possible, says Jani Westerlund, CEO of PR Rolls.