Pirelli Unveils Automatic Mixing System

Motorcycle tyres the latest to be made by MIRSPirelli has unveiled what it describes as “a completely new development in tyre production”, its Continuous Compound Mixing (CCM) system for the production of compounds. The system is being used at the company’s MIRS plant at Bicocca, near Milan. The plant measures 800 square metres and was built in only 24 months at a cost of 10 million Euro.

CCM, says Pirelli, is a logical extension of the MIRS project and the system is covered by seven patent applications, the first of which has been granted in the USA. It allows the mixing of up to 40 components, from polymers to additives such as silica or carbon black and the Bicocca pilot plant can produce 250 kg of compound an hour, which is scheduled to rise to 1000 kg/hr. Mixing lead time is reduced from 24 hours in the traditional mixing process to 4.

7 hours, plus there is an energy saving, with CCM energy consumption being 20% lower. The variability of the physical properties of the compound is improved too, being 70% lower.Pirelli Chairman Marco Tronchetti Provera said that, together, CCM and MIRS “would strengthen Pirelli’s leadership in high performance products and in growing and profitable sectors”, adding that the productivity and flexibility of the plant provides the answer to the needs of an automotive market that is evolving quickly.

Renato Caretta, Chief of Engineering Technology, said that the flow of CCM requires only two double screw extruders which are fed pneumatically and which work continuously without interruption and without the storage of raw materials to the final band that feeds the robots. By allowing total control of raw materials, temperatures and mixing conditions, the amount of carbon black in the working environment is drastically reduced with CCM; instead of the 10 mg/cubic metre allowed by EU regulations, the figure for the Bicocca CCM room is a mere 0.3 mg/cu.

m. Latest MIRS DevelopmentsAs well as the introduction of CCM, the MIRS programme continues to move forward on a number of fronts. The first of these is the sector of motorcycle tyres, which has always been an area where MIRS was considered to have great potential, in view of the greater uniformity supplied by the system, which in turn means improved safety for the bike rider.

This has been recognised by bike manufacturer Aprilia, which has approved homologation for the first MIRS motorcycle tyre on its RSV 1000 model. According to Aprilia, the tyre showed “a great balance between comfort and stability, setting a new benchmark” and “outstanding grip in braking”. The pilot module at Bicocca is due to lead to the installation soon of a MIRS motorcycle tyre production unit at the Metzeler factory in Breuberg, Germany.

Regarding truck tyres, Pirelli says that considerable progress is being made in this area and robots at the Bicocca plant are “learning” to handle truck tyres weighing upwards of 50 kgs.Work on MIRS car and SUV tyres is proceeding at full speed, with three MIRS lines at Breuberg producing Eufori@ run-flat tyres for the new Mini and two more lines due to come on-stream soon.There are two MIRS lines in operation at Pirelli’s Burton-on-Trent factory, one producing run-flat tyres in sizes from 16″ to 18″ and the other making SUV tyres in diameters from 20″ to 24″.

Outside Europe, Pirelli says that its plans for MIRS in the USA are on track, with completion of construction of the factory in Georgia. This is very close to start-up, with production scheduled to begin this month and, by the end of the year, three MIRS modules will be in operation in the USA, producing mainly SUV and off-road tyres..