Optimize operations with a Roll Cover and Maintenance Agreement
Sep 1, 2020
Valmet Roll Cover and Maintenance Agreement
Today's paper machines must run at very high speeds and efficiencies while producing high quality products. There is no time for unscheduled downtime or sub-par operation. Paper machines are complex systems and up to 60% of their value consists of rolls. Precision maintenance and communication provide the cornerstones for optimizing reliability. Sending rolls to multiple suppliers can be expensive, cause a loss in continuity and create extra burdens for roll management. A roll performance agreement can solve these problems.
Benefits
Eliminates unplanned downtime
Minimizes time roll is out of the mill
Keeps rolls in OEM condition
Improves roll run times
Reduces long-term maintenance costs
Improves performance with upgrades
Computerized tracking tools
A webinar was held which described the Roll Cover and Maintenance Agreement on November 18th, 2020. It can be viewed HERE.
Systematic approach for improving the performance and run time of rolls
Agreement based roll maintenance operations combines Valmet's latest roll technology and knowhow with the mill's experiences to solve roll performance challenges.
This means more revenue, better asset management, less risk and lower life-cycle costs in your operations. All roll agreements are tailored to match each mill's needs and address current issues. Agreements can include items from simply grinding, to new roll covers that reduce power requirements or increase life, open areas and patterns to improve dewatering, roll mechanical maintenance for increased machine efficiency and reliability, up to and including complete workshop operations at the mill site.
Many mills have benefited
Extended roll run times reduce maintenance costs
Reduced motor power requirements provide electrical savings
Increased dewatering for dryer steam savings
Improved sheet handling with fewer web breaks
Flatter CD profiles and better sheet quality
Average suction roll run time increased from 178 to 683 days (3.8x) with the Valmet Roll Cover and Maintenance Agreement.
How does the Agreement work?
Precision maintenance and communication are the foundation for Valmet roll service. Audits are performed to assess the situation of each roll, including mechanical components, roll cover, modernizations and in machine performance. Roll baseline performance and specifications are reviewed with the mill and opportunities for improvements are noted. Next, work scopes, specifications, potential performance upgrades and operating procedures are jointly developed, agreed upon and implemented. This roadmap provides a clear and consistent path forward to advance each individual roll's performance, reliability and run time. This results in consistent and higher paper machine performance regardless of which roll is running.
The agreement focuses on the total cost of ownership of rolls, including all needed maintenance, optimizations and parts.
Key details about the rolls and operation are carefully followed in the Valmet Asset Manager, an online tool. Parameters are tracked using maintenance events, roll run times and targets, along with roll specifications, modernizations and service reports. Incremental improvements are made to the rolls following the roadmap.
A Valmet roll agreement forms a partnership that allows early planning of work schedules one, two and up to five years in advance. This forward-looking preparation provides both the mill and Valmet opportunities to plan and agree on primary work scopes and schedules, reducing costs and roll turn-around times. Efficiencies are accomplished by having known work quoted and approved before the roll is removed from the machine, as well as having the known parts and planned openings in the roll shop schedule to allow the rolls to progress without delays as soon as they arrive.
The improvement possibilities are endless
Valmet offers a wide range of roll modernizations with customized upgrades and technologies. The most popular are:
iRoll: optimizes the CD temperature, moisture, tension and load profiles*
Valmet Suction Roll Upgrade Lock Seal: reduces power requirements, increases run time between roll changes and increases shell life.
Valmet Suction Roll Upgrade Edge Blow: Prevents trim from following into the press
Valmet Suction Roll Upgrade Edge Light: visual indication of suction box orientation and end deckle position inside the shell
Cover optimization: PressSim and other simulation programs to identify improved materials for increased run times and/or new patterns for better dewatering
Valmet Suction Roll Upgrade Seal Flow: keeps suction roll holes clean, reducing sheet breaks and transfer issues
Seal upgrades: prevents leaks from bellows seals by eliminating bellows seals
Condition monitoring: identify issues early with bearing and roll shape online monitoring
... the list is endless!
* The items measured and optimized depend on which rolls have iRoll installed.
Example savings achieved
In addition to the $62,500 reduced maintenance cost described in one of the figures above, here are two more representative examples:
$435,000/year from installing Valmet Suction Roll Upgrade Seal Flow.
$83,500 to $135,000/year from suction box redesign which reduced sheet breaks and wrinkles
For more information on optimizing your roll performance watch the webinar and contact your Valmet representative about an agreement.
