The most commonly known tool, the blade, is manufactured in composite or metal materials and must have mechanical and wear resistance characteristics such as to find the right compromise between life of the blade itself and the safeguard of the cylinder on which it works. ANDRITZ Bonetti (AB) offers a service that starts with advice on the best materials to use and the best solutions to adopt and ends with the maintenance of the complete doctoring system.
AB favors the use of blades made of composite materials – mainly glass fibers, carbon fibers and combinations of the two – which guarantee mechanical characteristics often comparable to those of metallic blades. Today, AB blades include all the qualities and materials currently used in modern paper making.
An example of AB’s research for the best is Leopard, a blade with considerable rigidity in cross direction and wear resistance superior to other materials on the market.
AB has developed doctor blades in fiberglass – BR Abrasive – with additives that minimize the risk of sparking on dryers: these blades help keep the cylinders clean with persistent stickies and are appreciated by the most demanding paper makers.
An experienced and proven partner to the global tissue machine industry
Blade is in fact the part of the doctoring system in contact with the cylinder and it is often required performance that is impossible to achieve if the other components are not in full efficiency. When designing and manufacturing the doctor body or beam one must take into account all the elements involved: each of these factors differ from machine to machine and requires the attention of an engineering doctor specialist to ensure the minimum possible deflection and the lack of vibrations. AB doctors are always box-shaped to better guarantee the solidity of the structure. The design of some systems may include a tray, sometimes heated, to collect debris out of internal wire rolls, upper rolls in the press section, suction rolls.
Doctor bodies are tailor made for each specific position of the paper machine. While the rigid blade holder such as Bonfirm a/o Super requires only perfect profiling, the flexible blade holder must be carefully maintained by taking care of periodic cleaning and alignment.
On flexible blade holders, the hoses must be replaced with the frequency indicated by the manufacturer: they must not get hard and must not lose air pressure to ensure uniform load of the blade over its length. AB suggests its Bon70, Bon 140 and Bon 250 tubes, each with a temperature resistance suitable for the different positions of the paper machine.
Stationary doctors cannot guarantee the result of cutting the material off the roll face, nor to avoid hard particles to stick into the blade tip and cause lines of dirt or even damage the surface of the cylinder. Electromechanical oscillators are the most common ones.
Their maintenance is often neglected and frequently one can find stuck oscillators with burnt motors or worn excentrics.
AB has developed a pneumatic oscillator (BonMatic) that requires a single air supply line and no external control panel. It offers considerable thrust, able to satisfy the oscillation needs of the most demanding doctoring and creping systems. Air consumption is minimal even if BonMatic is used on each doctor of the whole dryer section. Ease of use, compact dimensions and minimal maintenance make the BonMatic one of the most successful components supplied.
AB mainly uses self-aligning ball bearings with just a simple periodic greasing, they offer unparalleled durability and precision, so much so that they are adopted as a standard by major OEMs.
Lubrication often helps the cleaning action and surely extends the life of the doctor blades. AB suggests the use of showers. The Hi pressure ones are oscillated with BonSync, an electronic drive which, through its control panel, allows the finest adjustments. In conclusion, the above confirms the importance of relying on a specialist to guarantee the best possible doctoring: the blade cannot solve all the problems of cleaning the cylinders or detaching the paper by itself if all the components of the system are not in perfect conditions. It is clear now how essential is to use blade suppliers able to suggest the best solutions: companies like AB which boasts decades of experience working with paper mills and paper machine manufacturers all over the world.
ANDRITZ Bonetti
Established in Italy in 1923, Bonetti SpA has been successfully supplying the pulp and paper industry since the early 60s with the most updated portfolio of doctor, coater and creping blades and with complete doctoring systems as well. To meet worldwide product demands, four state of the art manufacturing facilities in Europe and North America are supporting another three licensee manufacturing plants strategically located in key paper manufacturing Countries.
Strongly focused that “innovation drives efficient papermaking”, Bonetti sinks its roots in a far long experience, but has always based its success and phylosophy on a timely tailored response to the ever-changing needs and demands of the markets it serves. Continuous investments in R&D, in specialized and constantly trained staff, in new production machines and the spraying plant, guarantee all Paper Mills around the world to benefit of some of the best products available on the market.
Last but not least is Bonetti’s Service: complete audit and maintenance of the doctoring systems and the blades in use, supply of spare parts, special checking and monitoring tools are only some example of this important technical plus that has become over the years an appreciated value added on the top of the products offered.
In 2022 Bonetti joins Andritz group becoming Andritz Bonetti and will continue to be a global competent and reliable partner of paper mills and paper-machine manufacturers worlwide.
Products
Blade holders, Coating blades, Creping blades, Doctor holding devices, Doctors and doctor blades, Laboratory for analysis and measures, Maintenance, Spare parts.
