Recently a stretch film manufacturer found score damage around the circumference of a 1.3 metre diameter chrome plated chill roll. The scoring had been caused by a metallic object, which had somehow been fed into the machine. Saras were contacted to carry out the repair of the roll. The repair was achieved by first removing all the ‘high spots’ created by the object and pre-treating the chrome surface to allow complete adhesion of the base coat of nickel. The score mark was then filled using a hard copper plate and all the excess copper removed by hand dressing to the existing cylinder profile.
Checks are made to ensure the cylinder surface is level with clocks and special cylinder gauges. The final operation is to cap the repair with a hard deposit of nickel cobalt and hand polish to achieve the original chill roll surface finish. The repair was carried out in-situ on the Customer’s premises without the removal of the chill roll from the machine. This was of great benefit to the customer in the minimum of down time of their machine and considerable saving in cost.
The new series of modern web presses created a problem for the processing by Saras operators and the access into the press. The presses’ cylinders are only accessible from inside a tunnel and are above head height. As the Saras repair process uses acidic and alkaline chemical electroplating solutions an entirely new plating method had to be devised to allow the operator to work cleanly and safely below the damaged cylinders and conform to the Customer’s health and safety regulations. Saras devised these new techniques for safe working of their operators. Saras also developed a lighter smaller switch mode power supply to allow this type of processing in the limited space allowed enabling the operator more versatility to carry out these difficult repairs.