Voith has launched an embedded sensing system that measures nip conditions inside paper machine roll covers while equipment is operating at full production speed, replacing intermittent static checks with continuous pressure data.
NipDynamics uses ultra-thin sensors built directly into the roll cover, where they measure pressure across the width of the contact area between rotating surfaces. Data is transmitted wirelessly and presented through a configurable three dimensional display, while historical measurements are retained for comparison over time.
The nip is the zone where two rolls, or a roll and another rotating surface, press together. Its geometry and pressure distribution influence several stages of paper production because the sheet is repeatedly squeezed, transferred, finished and wound as it moves through the machine.
Uneven pressure can affect more than the roll itself. Misalignment or changes in cover condition can contribute to non-uniform dewatering, surface variation, paper breaks or winding defects, depending on where the affected nip sits in the process.
Traditional nip analysis frequently relies on measurements taken while the machine is stationary and the sheet is absent. Those tests provide useful information about alignment and contact pressure under controlled conditions, but they capture a snapshot rather than the mechanical state of the equipment once speed, temperature, loading and the paper web are influencing it.
NipDynamics is designed to measure through those operating effects. Voith says the embedded sensors can run at full production speed and elevated temperature with paper passing through the nip, allowing engineers to compare static alignment with behaviour under load.
Roll covers deform, heat and wear during service, so a pressure profile established during a shutdown does not necessarily remain identical in operation. Continuous measurement shows whether loading changes with speed, thermal expansion or process conditions rather than requiring engineers to infer those effects afterwards.
The sensors record pressure across the full cover width at rotational frequency. Their low profile is intended to preserve the designed roll geometry and service life while adding measurement capability within the cover itself.
Because the sensor remains inside the operating roll, the same measurement system can follow gradual changes over weeks or months. Historical trends can distinguish a sudden deviation from progressive deterioration and give maintenance teams more evidence about whether intervention can wait for a planned outage.
Voith is applying the technology from forming and pressing through to reeling, although the same pressure measurement has different consequences at each stage. Earlier in the process, an uneven nip can influence moisture removal or sheet transfer, while downstream pressure variation can affect winding density and finished reel quality.
The company has reported several field applications. At a European MG cylinder installation, continuous measurements were used to optimise the nip profile and operating conditions over an extended period, producing documented savings of about €45,000 before the customer selected another roll for the system.
A reel drum installation demonstrated measurement at average loading of around 2kN/m. Low line load gives the sensor less pressure variation to resolve, so useful operation in that application provides evidence that the system can detect changes outside heavily loaded press nips.
At a tissue pressure roll, NipDynamics identified a local area of low line load that corresponded with a wet stripe in the sheet profile. Linking the quality defect with an observed mechanical condition narrowed the diagnostic work required to establish where the process variation originated.
Paper machines contain many interacting variables, and a defect visible at the reel may have been created much earlier. Pressure data captured at the time of the event allows roll loading to be tested directly as a possible cause rather than relying on a later static inspection after temperatures and loads have changed.
The same information can support maintenance planning. A profile that remains stable offers little evidence for an unscheduled shutdown, while a developing deviation can justify alignment or roll work during a planned outage before product quality or mechanical condition deteriorates further.
Embedded pressure sensing does not replace mechanical inspection, bearing monitoring, vibration analysis or conventional alignment methods. Nip behaviour still has to be interpreted alongside hydraulics, cover condition, sheet properties and the wider machine state.
Additional data can also become another burden if mills do not establish useful reference profiles and alarm limits. Different grades, line speeds and loading conditions can legitimately change the pressure pattern, so the system has to distinguish normal process variation from a mechanical condition requiring intervention.
NipDynamics moves roll covers closer to the condition monitoring model already used on rotating equipment, where decisions are increasingly based on observed behaviour under load rather than fixed inspection intervals alone. Its field installations show that the sensors can operate in production; wider deployment will determine whether continuous nip data becomes a routine roll cover function or remains concentrated on machines where downtime and quality losses justify the additional instrumentation.
