Manufacturing and design engineers to the converting, packaging, printing and composites industries
Chamber doctor blades (click to enlarge)

Carbon fibre doctor blades show advantages

Offering cleaner, cheaper and faster running, carbon fibre chamber doctor blades will ensure higher quality printing, reduced ink wastage and a safer working environment – so say specialist design engineers Delpro Limited, producers of the world's first successful doctor blade chamber system.

Designed to be as universally compatible as possible, Delpro systems are suitable for solvent, water-based or UV cured inks and coatings and may be retrofitted to any flexo printer or gravure coater with web widths ranging from 150 to 3000 mm. They may also be customised to meet the needs of specific applications and a wide range of anilox roll diameters can be accommodated with alternative profiles available.

The system comprises a fixed, reverse angle doctor blade in an enclosed chamber with a volume of only 0.7 litre/metre of width. 70% lighter than aluminium alternatives, one operator can therefore easily lift chambers in and out of the press without lifting equipment. With a stiffness and rigidity factor 300% greater than aluminium, the carbon fibre chamber ensures consistent doctoring and improved lay down.

In operation, a simple two-position mounting system automatically compensates for blade wear and ensures precision blade to anilox roll positioning on every set up whilst the completely tool-less blade and seal change-over ensures downtime and make ready times are kept to an absolute minimum.

Chamber removal and guaranteed repeatable replacement is made easy by a two-point location of the chamber mounting system. A pneumatic blade throw on/off is also provided. The small volume of the enclosed chamber compared to open tray systems ensures a significant reduction in ink and coating use as well as creating the cleaner working environment.

Pelikan Hardcopy, a leading supplier of industrial thermal transfer ribbons, is one company to take advantage of the benefits offered by carbon fibre. Seeking to improve machine speeds at its Turriff site in Aberdeenshire, a conventional open pan and adjustable trailing blade assembly on a reverse gravure Bone Markham machine was replaced with a Delpro Ecoflex carbon fibre chamber system.

The machine applies a solvent-based carbon black coating and on one particular product not only was the machine speed increased from 40 to 100 MPM, but: set-up time and coating and substrate waste in achieving defined coat weight was reduced; change-over time from one coating to the next was also reduced together with savings in waste coating volume; gelling of coating mix in the coating tray was eliminated; and evaporation of coating solvent was diminished due to the reduced open area of the chamber. Repeatability of coating weight without the need for operator intervention was a further significant benefit.

The immediate improvements resulting from this up-grade led to an order for similar equipment to be fitted to two further machines.