A Cannon solution for RIBA Composites’ all-carbon wheels
The Italian RIBA Composites designs, prototypes and produces structural parts and components in advanced Composite materials (using Carbon, glass and aramid fibres, etc.) for automotive, aerospace, naval and industrial applications. Based in Faenza since 1988, the Company currently manufactures in two production sites over 200,000 parts per year.
Specialising in several production technologies —including Hand layup and Autoclave cycle, Hand Layup and oven cycle (OOA), Infusion, Wet lay-up, Low-pressure RTM (LP-RTM), High pressure RTM (HP- RTM), Press moulding forged Carbon —RIBA recently invested significant resources for the development of Press moulding of long and short Carbon and glass (CF SMC/GF SMC) and High-pressure RTM in closed mould.
The dedication to these technologies allowed RIBA, in the past two decades, to supply specialised Composite parts to Ferrari, Maserati, Porsche, Ducati, Dallara, Agusta and other prestigious brands in automotive, motorcycle, aeronautic and marine fields.
A major breakthrough in their production capacity has been the recent investment in a complete Cannon moulding island composed by:
- A three-components E-System high-pressure dosing unit for Epoxy formulations, with one LN 10 three component mixing head and closed-loop control of output and ratio.
- A short-stroke press with 25,000 kN clamping force, 3.6 by 2.4 m platens and a very precise active control of parallelism for guaranteed planarity of the moulded parts.
This equipment is currently used by RIBA for the moulding of a sophisticated full-Carbon wheel, fruit of the two-years Europe 2020 CARIM Project.
A Joint European Project
Executed in partnership with leading European specialists in moulds, chemical technologies, testing & certification, the CARIM Project aimed to develop and commercialise a full-Carbon wheel manufactured with an automated high-volume process for the automotive market.
Developments in automated CFRP production technology generated a wheel that is 35% lighter than state-of-the-art Al-wheels, with the extra advantage of excellent mechanical performance. The manufacture of the wheels in an automated preforming HP-RTM process ensures short cycle times and lower costs compared to conventional composite technologies, which enables scale-up to series production and make the CARIM wheels competitive against current cast and forged Al-wheels and other emerging plastic wheel concepts.
Completed at the end of 2018, this FTI (Fast Track to Innovation) European project opened the way to the industrialisation of the moulding process of a very complex part, undergoing the most critical task of a vehicle: keeping driver and passengers safely connected with the road at the most extreme driving conditions.
A result obtained reducing the gas emissions of the vehicle, thanks to a substantial reduction of its weight.
A full-Carbon wheel for extreme performances
After finishing the European Project with the successful production of a generic five-spokes wheel, RIBA Composites started the development of a custom-designed wheel for a major European producer of top-class SUVs.
A 22” — nearly 56cm —diameter full-Carbon wheel with 10 spokes was requested, for a 285 mm wide pneumatic, to be supplied in industrial quantities: up to 20,000 parts per year, with possible growth in case of commercial success of the SUV model.
The state of the art of HP-RTM process chain utilised for this industrial production includes automated full-ply preforming of dry fibre reinforcements followed by resin impregnation and curing.
The preform manufacturing starts using coils of textile rein-forcements. 2-D textile layers are initially cut and stacked to the desired textile layup. The stack is then transferred to a full-ply draping mould to form a 3-D dry preform which is larger than the component’s end-geometry. After trimming to RTM mould cavity shape in an interposed process step the preform is transferred to the mould to be impregnated under high-pressure with an Epoxy resin formulation. Once the mould is closed, the resin and hardener mixture is injected into the cavity in one minute and flows through the fibres and impregnates the preform.
When the impregnation process is completed the resin undergoes a curing reaction, thanks to mould heating, and after 20-30 minutes, the wheel can be demoulded.
The moulded 22” wheel weighs 11 kg, composed by 60% of Carbon fibre and 40% of an Epoxy formulation with a Glass Transition (TG) point exceeding 200° C.
The final machining of the component, required to ensure absolute dimensional precision, is carried out in conventional milling/water jet-cutter centres.
Numerous advantages characterise both the process and the moulded full-Carbon wheel:
- The wheel is 35% lighter than a forged Aluminium model of equal dimensions.
- This weight reduction allows to redesign the whole suspension pack, with further reduction of the suspended mass.
- The manoeuvrability of the vehicle increases, providing a sportier driving experience.
- The wheel, simply coated with a glossy, transparent coat of protective varnish, looks nice and trendy.
- The method provides the highest design freedom in terms of number and style of the spokes.
- The system is industrially proven and suitable for the production of medium-high series of parts.
- Large structural components can be obtained with cycle times unthinkable of when using the traditional methods (Autoclave or oven cured).
- The possibility to fix metal inserts in the Carbon matrix during the preforming operation allows to obtain a wheel that can be fixed on the hub with a metal-to-metal contact, without any loss of torque at high rates of speed.
The moulded wheels, fitted with high performance pneumatics, have been submitted to the most extreme driving conditions, passing severe tests:
- The simulation of a full tour of the Nürburgring circuit, even with a red-hot brake disc heated at 700° C
- A 1.5 million cycles fatigue test with a severe flexural rotation of the spokes
- A long cycle of lateral and radial heavy impacts, simulating the drive over uneven pavement and pot-holes
- The resistance to the deformation caused by the tyre’s overpressure, inflating them at up to 10 bar instead of the normal 2.6
- The bolt-locking test, tightening the bolts with a torque several times higher than normal
Andrea Bedeschi, General Manager of RIBA Composites, commented the current phase of this innovative project: “We will present the wheel at the JEC Composites 2020 exhibition in Paris, next spring. We are ready to start production with this wheel, while we are already working at another, similar project. We aim to produce also our own designs, for the aftermarket. Our cooperation with Cannon for the definition of the most appropriate production technology and for the supply of the relevant equipment has been excellent. Press and dosing unit are fully suitable for high rate of production of quality parts, and we look forward to further developments in our relationship.”
Cannon has supplied HP-RTM injection and polymerisation equipment for a similar project to a leading supplier of all-carbon wheels.