The paper industry is undergoing an exciting transformation. While demand for newsprint and printed materials has significantly declined in recent years, other sectors are booming: packaging materials and paper filler products are in high demand due to global trade. Paper-based packaging for the food industry and, of course, toilet paper—something we came to value even more during the COVID-19 pandemic—are also experiencing surges in demand.

A key factor driving this transformation is the recyclability of paper products, which is becoming increasingly important across the industry. To meet rising demand while staying sustainable, high-performance machinery is essential. And this is where the right rolling bearings come into play: they ensure that machines operate efficiently under the demanding conditions of paper production.

Paper machines consist of various sections, such as the wet end, press section, and drying section. Each area places specific demands on the rolling bearings used. Reliability and precision are crucial, as machine failures can quickly result in significant costs.

Moreover, rolling bearings contribute to optimizing energy efficiency by reducing friction and enabling precise machine operation—both critical for sustainable production.

Challenges in Paper Production

High Loads and Speeds

The production of paper products imposes high demands on machines and their components. Rolling bearings used in paper production must withstand extreme loads, as machines often operate at very high speeds—particularly in the drying section. Here, the bearings are subjected to both radial and axial forces and must maintain functionality under these conditions.

Temperature Resistance

Temperature resistance is another critical factor, especially in the drying section, where temperatures can reach up to 200 °C. Standard bearings are typically stable only up to 120 °C, necessitating specialized heat-resistant bearing solutions and lubricants. Suitable materials include stainless steel, high-temperature steel, brass, ceramic (hybrid bearings), or PTFE.

Corrosion Protection

Corrosion-resistant rolling bearings are indispensable in the wet end and stock preparation areas. These sections are frequently exposed to moisture and chemicals, requiring corrosion-resistant materials such as stainless steel, aluminum, or ceramic.

Longevity

Machine downtime is costly, so bearings must have a long service life and require minimal maintenance. In the wet end, sealed bearings are often used, which are pre-lubricated. The sealing and lubrication prevent contaminants or moisture from entering the bearing, thereby extending its lifespan.

Precision

Imprecisely running bearings can lead to fluctuations in paper quality. These fluctuations not only affect the appearance of the final product but also result in significant production losses and increased waste. High-precision rolling bearings are therefore essential to ensure consistent paper production of uniformly high quality. In the paper industry, tolerance classes P6 and P5 are most commonly used, offering a good balance between cost, precision, and durability. For highly demanding applications requiring high speeds or extremely precise movements, P4-class bearings may also be considered.

Commonly Used Rolling Bearings in the Paper Industry

Certain types of bearings are more commonly used in the paper industry due to their properties, often in combination with housing and sealing. These include:

1. Spherical Roller Bearings
   • Description: Spherical roller bearings are ideal for compensating misalignment and angular errors, making them suitable for fluctuating loads and temperature-induced expansions. They are highly robust and can handle both axial and radial pressure.
   • Applications: Frequently used in paper machines, particularly in sections such as the wet end and drying zone, which experience constant, varying loads.
   • Brands in the PICARD Range: SCHAEFFLER (FAG), NACHI, NKE, NSK, NTN, SKF, SNR, STC-Steyr, TIMKEN
2. Cylindrical Roller Bearings
   • Description: Cylindrical roller bearings are often used in rollers and cylinders that must handle high radial loads in paper production. These bearings are ideal for high-load applications and offer excellent rigidity, allowing them to operate reliably even at high temperatures.
   • Applications: Found in drying cylinders, press rolls, and calender rolls, where high radial forces and vibrations occur.
   • Brands in the PICARD Range: SCHAEFFLER (FAG, INA), NACHI, NKE, NSK, SKF, STC-Steyr, UKF, ZEN
3. Angular Contact Ball Bearings
   • Description: These bearings are often used in applications requiring high speeds and the simultaneous handling of radial and axial forces. They provide high precision and stability.
   • Applications: Used in areas requiring high precision and low friction, such as winding machines, cutting machines, calenders, and printing machines.
   • Brands in the PICARD Range: SCHAEFFLER (FAG, INA), NACHI, NKE, NSK, NTN, SKF, SNR, ZEN
4. Tapered Roller Bearings
   • Description: Designed to handle combined radial and axial loads with high precision, tapered roller bearings are robust and offer high load capacity.
   • Applications: Found in drive shafts, roll bearings, and drum bearings, where fluctuating loads and precise alignment are necessary.
   • Brands in the PICARD Range: SCHAEFFLER (FAG), NACHI, NKE, NSK, NTN, SKF, SNR, TIMKEN, ZEN
5. Deep Groove Ball Bearings
   • Description: While less common in high-load applications, deep groove ball bearings are used in components with lower loads and speeds. They are known for their ease of use and high reliability.
   • Applications: Used in smaller machine components such as conveyor belt bearings or cooling rolls.
   • Brands in the PICARD Range: SCHAEFFLER (FAG, INA), NACHI, NKE, NSK, NTN, SKF, ZEN