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newsletter spring 2001 |
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Pollution
Prevention on a Stick
Cloquet-Diamond Brands turns birch logs
into toothpicks, corn dog sticks and craft sticks.
Keith Matzdorf, a senior chemical engineering
student at the University of Minnesota Duluth, worked as a
MnTAP intern at Diamond Brands to improve its conversion efficiency
of logs into the products. Changes stemming from the intern's
work helped the company improve product yield at the veneering
step by 11 percent.
Over 4,100 cubic feet of birch logs are
converted to product each day. One of its three manufacturing
lines accounts for nearly 50 percent of the birch consumed.
In the original process, birch logs were veneered into sheets
32.5 inches long, graded to remove sheets with defects like
excess knots and sawed into smaller "cards." The main sources
of waste were from: 1) operators applying the grading criteria
differently, and 2) edge trim waste and the saw kerfs. This
produced nearly 8,000 pounds of waste per day, almost 10 percent
of the wood passing through this process.
Changes Reduce Waste
A vision system was installed that
automatically grades the veneer sheets against a set standard.
Its consistency and ability to operate at a high speed reduces
the frequency of good veneer being rejected.
Sheet length was increased from 32.5 inches
to 12 feet and the cards were clipped/stamped from the veneer
rather than cut using a saw cut.
These changes helped reduce the waste by
nearly 5,000 pounds per day. The cost to implement the changes
resulted in a payback to Diamond Brands of less than two years.
For more information, contact MnTAP at 612.624.1300.
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