Small preforming and moulding equipment is available for laboratory and development use .
Large Cannon preformers are currently being used for Automotive Composites by leading OEM and Tier One suppliers .
This Cannon Patented solution allows for an efficient draping of the Prepreg sheet in the various sections of the mould cavity , avoiding the formation of wrinkles in the formed sheet . The grippers , mounted on a shuttling frame , travel the whole distance from the heating press to the forming press and can transport efficiently the whole range of sheets dimensions . The Cannon preformer can handle – with the units supplied up to now – preforms up to 2.5 by 2.5 metres , with a clamping force of 3,000 kN , but larger solutions can be provided on demand . The preforming press is a high-speed hydraulic clamp , with a thermoregulation system that keeps the tools at the temperature specified by the Prepreg suppliers to achieve the shortest preforming time . Additional grippers are installed inside the forming press to increase the active control during the forming of the parts , by holding and draping the material from all four sides . In less than a minute a complex preform is made , which is then extracted by a robot as the next hot Prepreg comes in from the heating station . The automatic unloading of the formed parts at the end of the cycle avoids any manual intervention of the operators within the press area . At this point the part can be extracted and trimmed to final size , using either a punching press or a robotized contour cutter , both trimming solutions available from Cannon .
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This step is necessary to obtain a finished part after the following operation .
Prepreg Compression Moulding : a Cannon Specialty For the compression moulding process of Prepregs Cannon Ergos designed a press with dedicated features to combine the main requirements of a fast cycle with the specific processing needs specified by each Raw Material Supplier for their materials :
· One or two lower mould halves shuttling on the front , which allows for a fast loading of the Prepregs and the unloading of moulded parts ,
· A revised hydraulic pack which provides both a fast approaching speed and a highly accurate control of the slower working speeds and p re s s u re s o n t h e m a t e r i a l . T h e t w o characteristics can be , when needed , combined with the use of a fifth central piston in addition to the traditional four on the press corners , which are equipped with a very precise Active Parallelism Control that guarantees perfect planarity to the mouldings .
For this technology a press with 25,000 kN of clamping force is available , usually with 3.6 by 2.4 m platens and 2.8 m daylight , with one or two lower platens shuttling on the sides .
A typical thickness of 2-4 mm characterizes most of the Composite parts made from Prepregs , that can be moulded in the largest sizes demanded by an automotive OEM . To ensure the full control of the mould , Cannon Ergos suggests the use of two additional dedicated devices : a sophisticated vacuum-control system for the accurate control of the in-mould vacuum and a thermoregulator able to keep the moulds at the high temperatures demanded by this process . By using different resin grades , that demand typical mould temperatures of 150-160 ° C or 190- 200 ° C , the current demoulding times for an average part vary from 15 to 5 minutes : an intense R & D activity is currently undergoing on new Prepregs , that aims to speed-up the curing , maintaining structural characteristics in the same range of moulded steel sheet or Aluminium . The Cannon press is already designed to perform a 3 minutes part-to-part cycle , including the service time on the shuttled lower mould half . When , at the end of the curing , the mould opens , the part is extracted automatically and it ' s ready for use . Its surface has acquired high gloss and the Carbon reinforcement is visible through a perfectly transparent layer of migrated resin . The only way to get an aesthetically perfect part is to respect the combination between mould temperature , clamping pressure and curing time . Each type of commercial Prepreg provides a nice result only if all parameters are kept under the strictest control !
Cannon , being able to supply all the required technologies and equipment with a “ single responsibility ” contract , provides a One-Stop- Shop approach to the Companies that decide to invest in complete manufacturing solutions for Prepreg-type as well as for HP-RTM Composites . This is a unique offer , in a competitive field where several producers of single pieces of equipment are simply not able to guarantee the success of the final result when a complex plant has to be put together !
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