Mill Improvements: Technology to Service Customers
By Pulp & Paper Canada
By Pulp & Paper Canada
Strathcona Paper, a division of Roman Corporation Limited, has been making recycled paperboard on the banks of Southern Ontario’s Napanee River since the early days of the twentieth century. With this…
Strathcona Paper, a division of Roman Corporation Limited, has been making recycled paperboard on the banks of Southern Ontario’s Napanee River since the early days of the twentieth century. With this long history, making a consistent, quality product from a variable fibre source has become a time-honoured tradition for the mill’s process operators. The single-machine mill produces clay coated folding boxboard, used mostly for consumer product packaging. All of the machine’s furnish is recycled waste paper fibre.
Extending the experience
Over the years, the mill had made some individual strategic investments to add value to the product, reduce costs and to improve productivity. But to stay competitive and profitable in today’s changing times, a major leap in process technology, process automation and quality management and business tools was required to build upon and extend the experience of Strathcona personnel.
In 1998, the mill team was invited by senior management to define a major capital investment program to enhance the mill’s competitive position and customer service capabilities. Improvements in safety, the working environment and training processes were also weighed heavily.
This $25 million plan was a major undertaking for an independent, single-mill company. The impact of the proposed portfolio of investments was carefully evaluated on a project by project basis to ensure each component would pass the intensive due diligence to validate the delivery of the ROI. The implementation of the various projects was phased first to upgrade the operators’ skills, improve board quality and then to increase production.
The multi-component strategic capital plan included: an additional filler stock cleaning system, a state-of-the-art process control and automation network, a new former supply system, a new machine chest, a digital speed and draw control system, a CD-controlled steambox, a rope threading system, additional drying capacity in the coater, a new warehouse and new integrated management and manufacturing information systems. Complementing the strategic plan, projects for liner stock fine screening and a new winder slitter and trim handling system were also implemented.
Starting with the customer
The strategic planning process started several years before the investment decision. The information needed to define the scope of the projects and their economic justification was gathered from customers and from within the mill. Customer surveys identified existing product qualities that were competitive advantages and also identified some areas where quality could be improved.
To support the internal justification, the mill used an existing information gathering system, which consolidated operator entries over three years. That database was used to analyze the internal mill operations. From this, the ROI available by reducing the internal costs of quality, improving productivity and reducing process costs was calculated. These performance indicators were used to evaluate each component of the plan and the aggregate results.
Producing a clean,
The incoming filler furnish is pulped in a continuous Black Clawson Hydrapulper. The furnish is fed first to Ruffclones and then coarse screens. Next, the new, low consistency cleaning system supplied by Kadant Black Clawson removes heavy and light contaminants in forward and reverse cleaning stages. The forward cleaning system has four stages of Ultra-clones; the reverse system has one stage of Xtreme followed by XX-clone cleaners. Cleaner feed pressure is controlled using variable speed drives. The cleaned stock is thickened on a Voith Paper Gravity Decker. The reject handling system includes a Posedon clarifier. A building addition houses the cleaning equipment.
All processes from stock prep to the reel plus the white water and effluent treatment are operated from a new central control room at the machine’s wet end using the new metsoDNA control network supplied by Metso Automation. All motor controls, continuous controls and sequential controls are consolidated in this network. This was the first installation of this product in North America.
Considerable time was invested to develop graphic pages that support the operators in their tasks. There are many sequential operations and long time delays in the process, so the operators are given numerous “count-down” timers to indicate when certain events – like screen flushing — are about to take place and when process changes or grade changes are expected to be seen on the machine. The vast amount of information and trending capability enables the mill personnel to diagnose and solve many process problems, improve quality and grade change efficiency. With the metsoDNA control network, operator skill levels have increased significantly.
A very high level of automation has been achieved. Proprietary algorithms have been developed to control very difficult processes such as the continuous pulper consistency control and thickener consistency control. When the machine tender gives his “stock on” command which delivers stock to the formers, the entire fibre line startup is automatically sequenced with interlocks all the way back to the pulper conveyer. Thereafter, the stock prep production automatically tracks the board machine production rate. A simple right-click on any graphic page brings up an HTML document describing the embedded logic of the controls, interlocks and trends.
When designing the automation and controls, particular attention was paid to stabilizing the furnish before it reaches each of the eight Horne hydraulic formers. The filler stock freeness is controlled using specific energy and online measurements from an Innomatic freeness sensor. Freeness stability of the filler stock has been improved by the installation of a new machine chest. This agitated chest has a thirty-five minute retention time so freeness changes are dampened, leading to more stable machine operation.
The operator selects the type of stock and ply weight to be applied by each former. The mill replaced the old, manually operated stuff boxes with three pressure-controlled ring headers. The feed-forward weight of each former is now controlled with great precision and stability. With these wet end controls — plus feedback from the PaperIQ scanner before the coater — the 3-sigma variation of basis weight is less than 1% of target. Strathcona uses 3-sigma rather than the more common 2-sigma because it is a more stringent measure of product variability. Coat weight, caliper, moisture and total weight are measured by the scanner at the reel.
A Metso/VIB SteamTech profiling steam box was installed on the “long-bottom” felt before the presses to improve profile control and provide production increases. Reductions as high as 50% in moisture profile variability have been achieved. Production has increased 4% on dryer limited grades.
More stable draws,
A Brock Solutions (SAF) digital progressive draw control system was installed to improve the coordination of the numerous machine drive sections during grade and machine speed changes, thereby avoiding breaks. The metsoDNA provides a single window interface to the SAF system. The operators now operate the machine with one master speed control — the first dryer section — and progressive draws in other sections. Strathcona is currently developing the tension control for the first and second calender stacks. These tension controls will automatically compensate for changes in moisture level and freeness changes from grade to grade. The progressive draw system has reduced draw-related breaks and allowed higher machine speeds. On January 24, 2002, the board machine set a new speed record.
To ensure efficient machine threading, a 3-rope system, custom designed by Ganotec and William Kenyon Inc., was installed from the first dryer section through to the reel.
Adapting to change,
the planned way
The simultaneous implementation of the new cleaning system, process improvements, new automation and drive systems could have been a dau
nting task for mill personnel to assimilate and manage. A one-machine mill cannot tolerate “future shock” that might result in lengthy learning curves and lost production as new equipment is commissioned. A phased, one-step-at-a-time implementation program was chosen so no unnecessary downtime was taken. This allowed the operators to learn the new technology in a gradual way.
ABGS (consulting engineering), the Nardella Group (construction management) and many of the major equipment suppliers adhered to a critical path schedule that avoided unscheduled lost production. The whole project was managed by Strathcona’s Jim Thornburrow. The new equipment implementation followed the fibre flow from the stock preparation onward. The new cleaning system was installed as a separate, satellite module parallel to the previous system. This allowed “on the run” commissioning.
Since this investment plan represented a giant leap in technology for Strathcona, a high priority was placed on the transfer and documentation of knowledge and best practices from experienced operators and training programs for the new technology. We knew that our operators were good board makers and the board making process hadn’t been changed fundamentally. With their support and involvement, the new information and technology tools would help them make better board.
Three experienced operators were re-assigned for nine months to a team that documented existing process technology and best operating practices. Claymore Inc. provided additional technical writers and illustrators to transfer the operator’s experience into electronic training manuals that are now available on the metsoDNA video monitors and on the mill intranet. Hard copy training manuals are often used for one-on-one training. Operators can also learn about board making from a RPTA (Recycled Paperboard Technical Association) multimedia training course also integrated into the network.
The experienced operators who documented the procedures then returned to the machine to help other operators. The new control room was built to encourage a more comfortable and productive communication between the stock preparation and machine operators. To help operators become comfortable with the Windows NT operating system used by metsoDNA, Strathcona Paper provided interest-free loans to employees to purchase home computers. More than 50% of Strathcona’s employees took advantage of this offer. The transition was also helped by the cooperative attitude of the union representing the production employees.
The phased installation also helped mill E&I maintenance staff to learn gradually the new automation and drive control systems and to develop self-sufficiency in maintenance and configuration skills.
Improved customer service
Strathcona Paper’s business has changed over the last five years. Now, certain customers with regular and recurring orders are receiving logistical support from Strathcona Paper. This support helps them to meet the short lead times and changing requirements created by their customer’s just-in-time delivery needs. A new 45,000 sq. ft warehouse extension was built so that the company could efficiently manage its Supplier Managed Inventory (SMI) program.
This SMI business model is supported by the new OptiVision Manufacturing Execution System (MES), supplied by Honeywell. The MES system is integrated with the Epicor financial management system. This new, integrated system tracks and manages roll quality, machine production information, production scheduling, warehouse tracking and shipping fulfillment. It improves customer service, since the status of every order can be quickly determined. The system interfaces to the company’s new intranet for desktop information sharing within the company.
Positioned for the future
“Applications within the new management and manufacturing information systems have provided us with better customer service today and a platform for enhancements in the future,” says Peter Paton, Director of Business Strategies and Logistics.
To date, the ROI and customer satisfaction targets of the project have been met. “Customers report improved board cleanliness and more consistent quality from order to order and roll to roll,” says Mark Sklar, president and chief operating officer of Strathcona Paper Marketing Inc.
To summarize, Bryan Best, president and chief operating officer of Strathcona Paper, assesses the impact of improved product, process and business information on their organization: “The ability of technology to create knowledge is what creates wealth, and it is knowledge that will take Strathcona Paper into the third millennium.”
Donald Duncan, director of operations, and Erik Altosaar, director of process control and automation for Strathcona Paper, a division of Roman Corporation Limited. David Lang, product manager, Metso Automation Canada Limited.