St Regis - The UK's largest manufacturer and recycler of paper
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| Friday 10 September, 2010 | Client Login
Recent Investments: Hollins
Optima had to be improved in order to satisfy more demanding print requirements in an increasingly crowded UK marketplace. The most important paper characteristic that had to be changed was the smoothness of the sheet, with good smoothness essential for good ink transfer and coverage.
To meet these customer expectations, two key areas for improvement were identified on PM1. The old calender unit needed to be replaced to ensure a constantly smooth, even sheet ideal for printing purposes. In addition, work had to be carried out to improve the bottom ply formation. If the previous sheet was calendered hard, the lumpy bottom ply would cause bruising through the sheet. This could show up as mottled areas when the paper was printed, unacceptable for areas of block colour print.
The rebuild, costing approximately £1 million in total took place in two phases. Stage one was the installation of the DuoShake unit on the bottom wire, to be fitted over a 24 hour shut in early November 2004. Stage 2 was the installation of the new calender unit, complete with the Calcoil caliper profile control which was fitted during an extended Christmas and New Year shut in December 2005.
The DuoShake unit comprises of a motor gearbox attached to the breast roll of the forming section which causes the stock on the wire to be shaken. The shaking results in a better formed sheet with lumps less likely to occur.
The new calender unit is a single nip, twin hard roll system. To ensure even caliper control, a Calcoil profiler was fitted to one of the calender rolls. This heats small areas of the roll surface, allowing slight variations in caliper to be corrected.
Smoothness Results
Smoothness results have been encouraging with Optima Silk now at the top end of the comparative smoothness scale, and inline with the market leaders.
