Despite the negative impact of COVID-19, the composite material market is expected to growth of 5% within the 2026.
The main technological advantages in this field come mainly from the aerospace and defence industry, sectors which are driving the market growth, but new applications emerge almost every day in different sectors.
A common factor, however, is the interest in very thin composite laminates, of variable length depending on the applications, with high performing mechanical, structural and resistance features.
For the production in continuous of these particular laminates, Cannon has developed an unwinding and moulding line for the production of an overlay, pre-impregnated multilayer, with a maximum thickness up to 3mm.
Plant and process description
The unwinding section
This first section consists in an unwinding station which can accommodate up to 18 reels of prepreg composite material.
Depending on the thickness of the laminate to be obtained, a series of rollers are unwound and the layers are passed through two pressure rollers, which allows the constant and uniform dragging of the overlapping prepreg layers.
At this point the material passes on a roller conveyor where an electrical device weld together the layers and prepared them to the next phase (operation to be done only at the beginning of production) and where the operator can perform a first visual inspection.
The consolidation phase
The material is driven into a hydraulic press with heated platens for consolidation.
The press, modularly structured to allow a distribution of the closing force, features a short-refrigerated area at the entry side of the material. This precaution is essential to avoid that during the heating process the resin flows in the direction of entry of the laminates, causing possible negative effects on the quality of the piece that would be obtained from the next moulding.
A dedicated system is used to unwind, at the inlet of the press, two release films that prevent the material to enter in direct contact with the press platens and avoid adhesion; the films are then rewound at the outlet of the press.
At the end of this process, the consolidated composite laminate obtained will have a desired final thickness according the number of layers used.
The heating module
After leaving the press, the material immediately enters a second heating station with radiating plates. In this phase, the material will complete the hardening process, while the newly unwound portion of the laminate is consolidating in the press.
Final check and winding
Once ready, the composite laminate passes over a second roller conveyor for further inspection. In order to facilitate the visual control of the lower surface of the laminate, an inclined mirror and dedicated lighting have been incorporated.
A second couple of rollers guides the material (without adding additional tensioning) through a laser reader that checks the consistency of the laminate thickness. Finally, the material is wound on a motorized reel, to be easily transportable and usable in the subsequent processing stages to obtain the final product.