Pulp industry

On-site machining, surface engineering and component refurbishment for pulp mills

Pulp production places demanding requirements on process equipment.

Continuous operation, moisture, chemicals, abrasive materials, contamination and mechanical loads can gradually cause wear, corrosion, erosion, surface damage and dimensional changes in critical components.

At the same time, many pulp mill components are large, heavy and integrated into the production process. Removing them for repair can require extensive dismantling, lifting, transportation and additional shutdown time.

PR Rolls provides specialised maintenance, machining, coating and refurbishment solutions for pulp mills – both on-site and at our workshop.

Our services are designed around the component and maintenance requirement:

Large or fixed equipment → Service on-site

Removable component → Refurbish at the PR Rolls workshop

The objective is to restore critical equipment efficiently, extend component service life and help minimise production disruption.

Maintenance Challenges in Pulp Production

Different components – common causes of deterioration

Pulp mill equipment operates in an environment where several deterioration mechanisms can occur simultaneously.

Typical challenges include:

• Abrasive wear
• Corrosion
• Erosion
• Chemical exposure
• Surface damage
• Dimensional wear
• Bearing and journal wear
• Damaged sealing surfaces
• Misalignment
• Vibration and imbalance
• Contamination and build-up

The correct maintenance solution depends on why the component has deteriorated and what function the restored surface or geometry must provide.

PR Rolls therefore approaches pulp mill maintenance from the application rather than from an individual technology.

A component may require machining.

Another may require a wear- or corrosion-resistant coating.

A third may require several operations:

Inspect → Machine → Restore geometry → Coat → Finish → Verify

On-Site Machining for Pulp Mills

Repair large components where they are installed

Many pulp mill components are difficult or expensive to remove from the production line.

PR Rolls specialises in bringing portable machining equipment and experienced personnel directly to industrial sites.

Depending on the component and repair requirement, on-site machining services can include:

• Turning
• Milling
• Line boring
• Drilling
• Grinding
• Grooving
• Honing and finishing
• Dimensional restoration

On-site machining can be particularly valuable when dismantling the component would add significant time and complexity to a shutdown.

Instead of adapting the component to a stationary machine tool, PR Rolls brings the machining solution to the component.

On-Site Grinding & Surface Restoration

Restore critical surfaces without removing the component

Large rotating and cylindrical surfaces can gradually lose their required geometry and surface condition because of wear, corrosion or mechanical damage.

Where technically appropriate, PR Rolls can perform grinding and surface restoration directly at the mill.

The objective can be to:

• Restore geometry
• Remove surface damage
• Correct uneven wear
• Prepare a surface for coating
• Restore the required surface finish
• Extend the service life of an existing component

On-site grinding can also be combined with coating and precision finishing where the component requires a completely renewed functional surface.

This creates a complete repair process without unnecessary transportation:

Measurement → Grinding → Surface preparation → Coating → Final finishing

Industrial Coatings for Pulp Mill Equipment

Engineer the surface around the operating environment

Many pulp mill maintenance problems begin at the surface.

Moisture, chemicals, abrasive material and contamination can gradually attack exposed equipment.

PR Rolls provides industrial coatings and surface engineering solutions for requirements such as:

• Wear resistance
• Corrosion resistance
• Erosion resistance
• Chemical resistance
• Release and non-stick performance
• Controlled friction
• Reduced contamination
• Dimensional restoration

Coating technologies can be applied both on-site and at the PR Rolls workshop, depending on component size and maintenance requirements.

PR Rolls' coating portfolio includes thermal spray and carbide coating technologies as well as specialised functional surfaces developed for different industrial applications.

The starting point is always the same:

What is damaging the existing surface – and what properties does the new surface need?

DD Washer Maintenance & Solutions

Specialist expertise for critical pulp washing equipment

DD washers are important production assets in pulp mills, and their performance depends on the condition and interaction of several mechanical and sealing components.

Wear, dimensional changes and deteriorated sealing surfaces can gradually affect washer operation.

PR Rolls provides specialised services and solutions for DD washer maintenance, refurbishment and performance improvement.

Depending on the maintenance requirement, PR Rolls capabilities can include work related to:

• Drum surfaces
• Sealing areas
• Mechanical components
• Surface restoration
• Machining
• Measurement
• Alignment
• Coating
• Component refurbishment

By combining on-site machining and surface engineering, large DD washer components can in suitable cases be restored without unnecessary removal from the mill.

DD Washer Sealing Solutions

Control the interface between moving and stationary components

Sealing is a critical part of DD washer operation.

PR Rolls has developed dedicated DD washer sealing solutions for these demanding applications.

Rather than treating the seal as an isolated spare part, the complete interface should be considered:

Seal + Counter surface + Geometry + Alignment + Operating conditions

A new sealing component alone cannot compensate for an incorrectly dimensioned, worn or damaged counter surface.

PR Rolls' broader capabilities in machining, measurement and surface restoration make it possible to address the condition of the surrounding equipment as part of the maintenance strategy.

For detailed information, see DD Washer Seals.

TwinRoll Press & Compact Press Maintenance

Service and refurbishment for pulp washing and dewatering presses

In addition to DD washer services, PR Rolls provides specialised maintenance and refurbishment services for Valmet TwinRoll Presses and ANDRITZ Compact Presses used in pulp washing and dewatering applications.

These presses operate continuously under demanding conditions where wear, corrosion, mechanical loads and process conditions can gradually affect critical components and functional surfaces.

PR Rolls can support maintenance projects involving Valmet TwinRoll Press and ANDRITZ Compact Press equipment, combining our expertise in industrial maintenance, precision machining and surface engineering.

Depending on the equipment, component condition and required scope, services can include:

• Inspection and condition assessment
• On-site machining
• Grinding and surface restoration
• Repair of worn or damaged areas
• Dimensional restoration
• Industrial coatings and surface engineering
• Measurement and alignment
• Refurbishment of suitable removable components

The appropriate maintenance strategy is determined according to the actual component condition, wear mechanism and operating requirements.

For large or difficult-to-remove components, PR Rolls' on-site capabilities can reduce the need for extensive dismantling and transportation. Suitable removable components can instead be refurbished at the PR Rolls workshop.

Valmet TwinRoll Press → Inspection → Repair or machining → Surface restoration → Verification → Continued production

ANDRITZ Compact Press → Inspection → Repair or machining → Surface restoration → Verification → Continued production

By combining specialised machining with coating and surface engineering, PR Rolls can address both dimensional and surface-related maintenance requirements within the same project.

 

Supporting the Lifecycle of Existing Press Equipment

The objective is not simply to repair an individual worn area.

PR Rolls evaluates whether existing components can be repaired, restored or refurbished for continued operation before replacement becomes necessary.

This lifecycle approach complements our broader pulp-industry capabilities for DD washers, pulp washing equipment and other production-critical process components.

Pumps, Valves & Process Components

Refurbishment beyond rolls and cylinders

PR Rolls' pulp-industry capabilities are not limited to large rolls and cylindrical equipment.

Pulp mills contain many other high-value components exposed to wear, corrosion, erosion and chemical environments.

Suitable applications can include:

• Pumps and pump components
• Valve components
• Shafts
• Sleeves
• Bearing areas
• Sealing surfaces
• Hydraulic components
• Other metallic process components

Where the underlying component remains technically suitable, machining and surface engineering can provide an alternative to complete replacement.

A typical refurbishment process can include:

Condition assessment → Machining → Dimensional restoration → Coating → Precision finishing

This can be particularly valuable for specialised components with high replacement costs or long delivery times.

Repair of Worn Shafts, Journals & Bearing Areas

Restore the damaged area instead of replacing the complete component

Localized wear is common in industrial equipment.

A bearing seat, shaft, journal or sealing area may become worn while the majority of the component remains in good condition.

PR Rolls can evaluate suitable components for dimensional restoration using machining and surface engineering technologies.

For certain local repairs, brush plating can be used to deposit metallic material selectively onto the damaged or undersized area.

Potential applications include:

• Bearing seats
• Journals
• Shafts
• Sealing areas
• Local corrosion damage
• Scratches
• Dimensional errors
• Manufacturing and machining defects

After restoration, the repaired area can be precision-finished to the required dimensions.

Workshop Refurbishment for Pulp Mill Components

Complete maintenance when the component can be removed

On-site repair is not always the most appropriate option.

When a component can be efficiently removed and transported, PR Rolls' workshop provides the possibility to combine several maintenance operations into one refurbishment project.

Depending on the component, workshop services can include:

• Incoming inspection
• Condition assessment
• Mechanical maintenance
• Precision machining
• Grinding
• Surface restoration
• Industrial coating
• Precision finishing
• Dynamic balancing
• Final inspection

This can be applied to suitable rolls, cylinders, pumps, hydraulic components, valves, shafts and other industrial machine components.

The appropriate service route depends on the component:

Difficult to remove → Repair on-site

Efficiently removable → Refurbish in the workshop

Dynamic & Field Balancing

Reduce forces generated by rotating imbalance

Rotating pulp mill equipment can develop imbalance as a result of wear, repairs, material loss, deposits, coating or changes to the component.

Excessive imbalance can contribute to:

• Vibration
• Increased bearing loads
• Mechanical stress
• Premature component wear
• Reduced machine stability

PR Rolls provides dynamic balancing at our workshop and field balancing for suitable equipment on-site.

Balancing can also be integrated into a wider refurbishment project after machining, grinding, coating or mechanical repair.

Importantly, vibration does not always mean imbalance. Bearing condition, alignment, mechanical looseness and other factors should also be considered when determining the cause.

Measurement & Alignment

Accurate information before corrective work

Effective industrial maintenance begins with understanding the actual condition and geometry of the equipment.

PR Rolls provides measurement and alignment services for suitable pulp mill applications.

Measurement can be used to:

• Verify component geometry
• Identify dimensional deviations
• Support machining decisions
• Check alignment
• Establish the scope of repair
• Verify the result after maintenance

This is particularly valuable for large installed equipment where dimensional relationships between components can affect the complete machine.

Measure first → Correct what is required → Verify the result

Repair, Refurbish or Replace?

Extend the lifecycle of existing pulp mill equipment

A worn component does not automatically need to be replaced.

Many industrial components are designed around a substantial underlying structure that can remain serviceable even after the functional surface or local areas have deteriorated.

Depending on condition, PR Rolls can evaluate whether the component should be:

Repaired – correct local damage.

Machined – restore geometry or dimensions.

Recoated – renew or change the functional surface.

Refurbished – combine mechanical and surface restoration.

Modernised – modify an existing component for future operating requirements.

Replaced – when continued refurbishment is no longer technically appropriate.

The objective is to make the decision according to actual component condition and future production requirements, rather than automatically replacing equipment because one surface or area has reached the end of its service life.

Planned Shutdown & Maintenance Support

Coordinate specialised services around the available maintenance window

Pulp mills operate continuously, making planned shutdowns critical opportunities for maintenance.

When several operations are required on large production equipment, coordination becomes particularly important.

PR Rolls can combine multiple specialised services during the same maintenance project, reducing the need to coordinate separate suppliers for each operation.

Depending on the project, this can include:

Measurement → Machining → Grinding → Surface restoration → Coating → Finishing → Verification

Pre-shutdown planning is particularly valuable for on-site projects.

The component, damage, required tolerances, available working space and production schedule can be evaluated in advance so that equipment and personnel are prepared for the available maintenance window.

From Individual Repair to Component Lifecycle Management

PR Rolls' pulp industry services are designed to support equipment throughout its lifecycle.

A component may first require measurement or local repair.

Later it may require more extensive machining or a new functional surface.

Eventually, complete refurbishment or replacement may become appropriate.

This creates a lifecycle approach:

Production → Inspection → Maintenance → Repair → Surface restoration → Continued production

Where appropriate:

Refurbishment → Modernisation → Continued production

And eventually:

Condition assessment → Replacement

By combining on-site services, workshop refurbishment and surface engineering, PR Rolls can select the appropriate maintenance route according to the component rather than being limited to one technology.

Why PR Rolls for Pulp Mill Maintenance?

Multiple specialised capabilities from one industrial service partner

Pulp mill maintenance often requires several different technologies.

PR Rolls combines:

On-site machining + Grinding + Industrial coatings + Workshop refurbishment + Measurement + Alignment + Balancing

This is particularly valuable for large, high-value components where a surface problem may also involve geometry, alignment or mechanical condition.

Our background in pulp, paper and board production provides an understanding of continuous industrial processes where equipment reliability, shutdown duration and component performance are closely connected.

The objective is not simply to complete an individual machining or coating operation.

The objective is to restore the component efficiently and prepare it for reliable continued production.

Frequently Asked Questions About Pulp Mill Maintenance

What services does PR Rolls provide for pulp mills?
PR Rolls provides on-site machining, grinding, industrial coating, measurement, alignment and field balancing, as well as workshop refurbishment, precision finishing and dynamic balancing for suitable removable components.

Does PR Rolls provide DD washer maintenance?
Yes. PR Rolls provides specialised maintenance and surface solutions for DD washers as well as dedicated DD washer sealing solutions.

Can large pulp mill components be repaired on-site?
In many cases, yes. PR Rolls specialises in portable machining and surface technologies for large industrial components where dismantling and transportation would be inefficient. Feasibility depends on the component and required repair.

Does PR Rolls only work with rolls and cylinders?
No. PR Rolls' capabilities can also be applied to suitable pumps, valve components, shafts, bearing areas, hydraulic components and other industrial process equipment.

Can PR Rolls provide wear- and corrosion-resistant coatings?
Yes. PR Rolls provides industrial surface engineering solutions for requirements including wear, corrosion, erosion, chemical exposure, contamination and other application-specific surface challenges.

Can PR Rolls restore worn dimensions?
For suitable components, yes. Machining and coating or plating technologies can be used for dimensional restoration. Brush plating can be particularly useful for local areas such as shafts, journals and bearing seats.

Does PR Rolls perform both on-site and workshop repairs?
Yes. Large or difficult-to-remove components can often be treated on-site, while removable components can be refurbished at the PR Rolls workshop.

Can PR Rolls support planned pulp mill shutdowns?
Yes. On-site machining, grinding, coating, measurement and other specialised operations can be planned around scheduled maintenance shutdowns. The required scope and feasibility should be assessed in advance.

Keep Critical Pulp Mill Equipment in Production

Pulp production places severe demands on equipment surfaces, geometry and mechanical components.

When wear, corrosion, erosion or dimensional changes begin to affect equipment, replacement is not always the only solution.

PR Rolls combines on-site machining, grinding, surface engineering, coating, measurement, alignment, balancing and workshop refurbishment to restore suitable pulp mill components for continued operation.

From a DD washer or large installed component to a pump, shaft or other removable process component, the starting point is the same:

Understand the equipment → Identify the problem → Select the appropriate repair technology → Restore the component → Return to production

Contact PR Rolls to discuss maintenance, refurbishment or surface engineering for your pulp mill equipment.