In June 2002 Glasgow Engineering won the contract to design and manufacture a new Heavy Press Roller for Starwood Australia (now Carter Holt Harvey Pine Panels) to replace an existing roller that had broken the main shaft. Due to the extreme pressures that are required in the manufacture of MDF board this roller had been previously plagued by failures. Glasgow Engineering were asked to produce a more reliable design that would not fail as this was a critical part of the plant, our roller was very heavy in its construction and incorporated removable stub shaft ends to make bearing and shaft changes easier, reducing down time at the mill. 

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We started with a piece of 600mm od x 500mm id hollow bar x 3.5 meters long weighing 2.8 ton.
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Two butts were machined from solid 500mm diameter K1045 weighing 800 kg each. Our design required the bore to be tapered to increase flex toward the inner section of the roller to reduce cracking and fatigue.
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Two bolt on stub ends were machined from 230 diameter K1045. The idea behind the bolt on stub shaft was to facilitate an easy exchange in case of bearing failure in the future.
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The main drum was bored for the interference fit of the butts.
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The roller was dynamically balanced prior to fitting the ends
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The ends were shrunk down using 500 litres of liquid nitrogen and the roller was heated up to create an interferance fit on the ends
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With the ends shrunk and welded into position the stub shafts were fitted and final machining undertaken
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Once the outside was machined it was then linished so no tool marks were present on the surface
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The completed roller ready to fit on site, this roller never failed again
Doosan Nanni Kubota Yanmar Kohler Pramac Aga Rayburn Falcon Liebherr Cheminees Philippe Morso Lopi