Bespoke covers from machinery protection specialist Beakbane are helping print industry supplier Sandon Global maintain micron accuracy in the laser engraving of ink transfer anilox rolls.
Sandon Global specialises in the manufacture of the anilox cylinders, which are used in printing presses to transfer a carefully controlled amount of ink to the printing plate.
These are made by using high-energy plasma spraying to deposit a very hard, dense chromium oxide coating on a steel cylinder. The cylinder is then ground to the diameter required and laser engraved with a precise pattern of cells that hold the ink.
As Sandon Global’s production manager Gary Carmichael explains: “The laser is focused at the surface of the roller and vapourises the ceramic to produce microscopic cells of varying depths and screen sizes – and that controls the weight of ink coat you transfer to the printing plate.”
Screen sizes can vary from 50 to 1,800 lines per inch, with cell depths varying from 300 microns to just one micron.
Sandon Global has invested heavily to create a facility that assists engraving consistency. The laser engraving department works in clean room and climate controlled conditions with anti-vibratory flooring to increase the stability of the product.
So when Mr Carmichael saw an opportunity to further enhance the consistency and accuracy of the machines he turned to Beakbane.
As he explains, the traverse equipment on the laser engraving machine includes a modular robotic lead screw, support rails and four linear bearings. As supplied, the laser engraving machine did not provide any protective cover for these mechanisms.
But the dust from the ceramic that has been laser machined from the surface of the roller is very abrasive and Mr Carmichael realised that any contamination of the guide rails or bearings could compromise the accuracy of the machine.
Beakbane had already successfully upgraded two of the grinding machines that prepare the rolls, replacing heavy steel covers with light fabric covers and reducing the machines’ footprint, so he asked them to come up with an answer to this problem too.
Beakbane’s solution was a pair of fabric concertina covers that fit over the traverse mechanism on either side of the engraving head. It chose this type of fabric concertina cover because they are light, durable and give complete protection against dust and abrasive particles. It has supplied this type of cover for many similar applications and its in-house 3D CAD facility and extensive manufacturing and testing capabilities mean it can readily tailor them to a customer’s specific requirements.
In this case the two covers for Sandon Global’s laser engraving machine each extend to around 4.6m – the maximum length of the machine bed – and are around 500mm wide.
Mr Carmichael says: “I have been very pleased with Beakbane’s service and the solutions they have come up with to enhance our machines.