MillTown Paper converts severely damged rolls to saleable paper once again and has found a way to fix a problem of broken load cells
May 2008
A Pulp & Paper Special Report
These days, recycling is 'in'; and MillTown Paper is an expert. The company salvages good paper out of bad. It buys damaged paper, mill excess, overruns, side trims, printer or publisher excess inventories, job lots, overruns and field rejects and makes useful products from them.
Rolls of paper that have been water damaged, or have crushed cores or crumpled edges, are out of round, or even those that may have fallen out of a truck; all of these have imperfections which cause the rolls to run with serious vibration.
MillTown can run rolls of any grade of paper or board up to 110 in. wide with cores from three to 12-in. internal diameter.
Plant manager Jerry Warning says, "We run a 76-in two-drum Cameron rewinder that we've designated for 'the worst of the worst' rolls. For a long time, we had problems with the rolls because the vibrations caused the load cells we were using to break. The beams would break under the stress and we frequently had to replace them."
MillTown, which employs about 45 workers and uses four rewinders, is a re-seller of paper it has salvaged. It does rewinding and slitting, sheeting and trimming and takes pride in custom converting. The company will purchase the materials or contract to convert it for a customer. Although 90% of the jobs are for printing and publishing paper it buys and converts for their customers – MillTown also does contract work for paper merchants, brokers and paper distributors, says company president Greg Duerr.
The winders have a maximum roll width of 110-in. It has done jobs as small as one or two rolls, and as large as 12,000 tons total.
In Need of a "Fix"
Seeing the expense and time loss from broken load cells, MillTown turned to The Montalvo Corporation of Gorham, ME, industrial web control systems specialists, for a "fix."
Warning says, "Montalvo came up with a new load cell that has fewer moving parts and we tried them. Not only did it fix the problem, we've now run the new load cells for more than two years with no problems, and we now are able to run the damaged rolls four to five times faster than before, even with the vibrations, and the load cells are no worse for the wear. We have increased production greatly. And we have not had to replace any load cells."
Montalvo sales representative for MillTown, Patrick Swiekatowski, says the aluminum beams in the load cells frequently broke from the vibration. "The problem was with a traditional cartridge-style load cell that clamps to a dead (stationery) shaft idler roller where the load cell supports the roll."
In an initial trial, company president Ed Montalvo had a Montalvo U-Series load cell installed in the place of the old load cell. The U-Series uses a pillow block bearing to help support the roller. "In addition, the U-Series has fewer parts, a stronger beam, is bigger and more robust, is bolted to the machine's frame and any vibrations are shared across a larger surface without damaging the sensor," he says.
The U-Series has a lower profile with a footprint similar to most competitors' models. Its mechanics have been simplified, the beam is easily accessible, it is water resistant, is constructed of stainless steel, and comes in four sizes with load ratings ranging from 50 to 22,500 lb. And it works in a high-vibration environment.
The improvement has been critical for MillTown, which often runs lightweight coated papers (32-50 lb basis weight) for web-fed printers to use for magazine inserts, catalogs and other end products. Warning says, "In the two and a half years since we started using Montalvo load cells, we have not had to replace a single one and that has kept our rewinders running."
The Montalvo Corporation specializes in the analyzing, upgrading and servicing of customer's web control equipment. Montalvo manufactures and services a wide range of web control products for the converting, paper, foil and nonwovens industries. Montalvo products include brakes, clutches, electronic tension control devices, load cells, indicators, web guiding equipment and safety chucks
For more information, visit: www.milltown.com; email gduerr@milltown.com or info@milltown.com.
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