Composite doctor blade body by Fibercompositi


Fibercompositi was born in the eighties as a supplier of composite material components for the textile machinery industry, responding to the needs of frame builders looking for innovative solutions to overcome the limits of light alloy products. Over the years, technical and technological development has allowed the company to open up to new markets, including flexo sector.

By F. Ciatto, D. Zanolini – Direzione Tecnica Fibercompositi

Composite materials are used instead of metallic ones, where it is necessary to improve static and dynamic performances and resistance to corrosion; further benefit is the reduction of mass which involves less inertia and greater handling.
Fibercompositi has been producing carbon fiber rollers and cylinders for some years, supplying the major European manufacturers of flexo machines. The frequent contacts between the various R&D teams have been fertile ground for the growth of new proposals and ideas concerning the development of the doctor blade holder. We immediately understood the need of each single partner to create a replacement and interchangeable component with all the already existing parts, thus also respecting the doctor blade geometries which are the “trademark” of each manufacturer.
Starting from this base, Fibercompositi R&D department had to search for a solution for the production of the piece, focusing on innovative methods and technologies that would allow the creation of a “tailor-made” carbon fiber doctor blade body chamber, allowing, for example, to use their own blade-holding closing systems, loading/unloading/washing systems, machine locks, etc.
The economic advantages for the customer of not having to redesign and possibly produce “ex novo” all these components on new machines are added to the possibility of being able to retrofit already installed machines without additional assistance costs, whose users need an increase of performance.
So far everything is normal … but … when it comes to carbon fiber products, moreover personalized, one of the recurring objections is “too expensive!”, consequently another of the main inputs was the containment of the cost of the product. These premises stimulated the creativity of Fibercompositi R&D team that took up the challenge, and, by patenting a new production system, made it possible to satisfy every need while containing costs.
Each new request for the development of these components begins with the design and FEM analysis phase that allows us to identify the right relationship between weight reduction and stiffness: typically with a 35-40% weight reduction compared to the same component in aluminum, we are able to obtain a higher stiffness of 15-20%.





Subsequently, in collaboration with the customer, we study the best possible solution respecting the original geometry and possibly adapting the piece to the various components of the final assembly and we prepare all the inserts for assembly in stainless steel to ensure resistance to corrosion. This study phase precedes the design and construction of the equipment necessary to obtain the piece.
Thanks to our production technology, the inking chamber is obtained by moulding, thus avoiding removal processes which, by making the fibers emerge, could compromise their impermeability with the consequence of ink contamination. Normally we are also able to adjust any longitudinal pre-curvature of the doctor blade body, satisfying the setting specifications on the machine. This peculiarity finds considerable confirmation in the case of very large tables, allowing to keep contained operating pressures.
The resin we use has been tested to evaluate its resistance to the major solvents and primers used in the printing industry, and, thanks to the results obtained, we also equip digital printing machines by replacing the aluminum or technopolymer parts whose corrosion and low rigidity limit their use. Willpower, commitment, flexibility and technological innovations are Fibercompositi’s answer to the needs of the flexo market.