Service support for roll covers.

Increasing quality requirements and the constant optimization of machine performance are on the agenda for anyone who wants to stay ahead in the future. Paper manufacturers are faced with increasing demand for more efficient use of resources and cost effectiveness in production, without affecting product quality. Considering the complex aspects of the equipment in an ever-faster world, manufacturers increasingly resort to external service providers.
SchäferRolls, a worldwide established producer of polymer-based roll covers with its headquarters in Renningen (Germany), is expanding its product range by focusing on application and service support around roll systems.

SCHÄFERROLLS offers industrial companies an all-round range of solutions for operating, managing and maintaining roll systems – from planning, design and execution to initial start-up, servicing and integration into running processes.
The detailed analysis of an application in order to determine the ideal roll cover design as well as helping with the optimization of process parameters are just as much part of the service catalog as the preventive maintenance.

The example of a Belgian customer shows that a dewatering analysis can not only contribute to the increased performance of the individual presses. Rather, the SchäferRoll’s SurfaceOptimizer (SSO), a computer simulation tool to design an optimal roll cover, has created a design that optimizes the performance of the first and second press through open areas and increased void volume while providing the necessary stability for the third and fourth press.
Thus, this cover can be used flexibly in all four positions which increases the availability of reserve rolls and significantly reduces all the maintenance costs.

A customer in the Netherlands complained of vibrations and resulting regular paper breaks at the film press rolls. He therefore sent the rolls for investigation to SchäferRolls, where massive detachments of the cover were determined. The good SchäferRolls references for this roll position convinced the customer to buy two new rolls including complete service support by SchäferRolls, such as nip measurements, thermographic analysis and on-site consultation. After start-up, the customer still had problems with wrinkling. Supported by a thermographic analysis, the problem could be identified directly in the wire section and thus be eliminated. Due to the good experience with the covers as well as the service both roll pairs for this position have been covered at SchäferRolls.

Nip measurement.

Regularly, costumers take advantage of ultrasonic measurement which allows destruction-free inspection of the roll cover’s material and bonding properties, to contribute to the operational reliability of the paper machine. Specially trained technicians from SchäferRolls have comprehensive expertise and experience in performing ultrasonic inspections and interpreting the measurement results on a case-specific basis. This allows discovering risk-relevant defects and covering separations at an early stage, before they cause damage in the machine.

Several customers have repeatedly taken advantage of the SchäferRolls shutdown service because the time of a scheduled machine downtime is being used effectively. SchäferRolls experts will be on-site during a system shutdown to investigate all application-relevant requirements and operating conditions for the rolls defined in advance with the customer. Based on a comprehensive report with photo documentation, derived actions can be weighed up with the aid of a traffic light system and implemented according to the urgency.

Thermographic analysis.

In partnership with countroll, SchäferRolls offers a sensor data service to analyse weak points, such as slippage problems on wire driven rolls in a paper machine. This service includes the complete hardware and its installation on the machine. The measured data is analysed in a cloud-based platform and interpreted based on SchäferRolls’ experience. Based on the analyses, solutions for optimizing the machine are developed together with the customer.
A sensor that measures the number of revolutions, speed, speed changes, temperature and vibrations has been developed and affixed to the roll.
This data is also displayed and managed in the cloud-based platform. SchäferRolls assists the customer with installing, setting parameters, commissioning and downloading the sensor’s data. The sensor was originally developed for industrial rolls but is now used in numerous applications. In the paper industry, there is also huge demand for vibration measurements (early warning) as such vibrations are often the result of bearing damage and/or a misalignment of the roll systems. Since the sensor is mounted directly onto the roll (on-axis and off-axis), the sensor detects malfunctions with the bearing housing much faster than static piezoelectric sensors.
In addition to using the sensor as an early warning system for vibration problems, tests are currently being conducted on wire driven rolls in two paper mills to detect and visualise slippage issues.
The results of these tests will also assist in the design of an optimum roll cover to ultimately reduce maintenance and operating costs as well as prevent unscheduled machine outages.