AFTER an absence of several years, the satellite show on Rubber is back at this year’s PlastMilan exhibition in Italy. Under the patronage of the rubber association Assogomma, a pavilion has been slotted for rubber manufacturers with several exhibitors covering rubber processing plants, which traditionally exhibit at the show, as well as rubber producers and companies that process elastomers, natural and synthetic rubbers.
TPE compounds for a range of sectors
New machines for extrusion Pomini Rubber & Plastics will present its Convex new generation of twin-screw dump extruders for treating rubber compounds produced in the internal mixer. With 150 installations under its belt, Pomini says it has used the experience to improve the screw geometry, roller head and cylinders design and the ease of cleaning and cooling properties. The result, it says, is an innovative machine, compact, versatile and reliable, which is characterised by a high output, optimised temperature control and low compound contamination. These characteristics make the Convex ideal for making tyres and technical rubber goods. Milex, a variant of Convex, will also be presented at the show. The machine allows the replacement of open mill under internal mixers, ensuring the same performances that involve distribution and recovery of incomplete mixing. The screw design of the extruder is optimised with regard to flow behaviour by means of FEM analysis, thus allowing for lower energy input. In addition, the use of a cantilever motor gearbox for each screw and cylinder roller head allows a compact layout. Colmec will introduce its new Triplex unit for the production of rubber hoses with a co-extrusion head composed of three parts with diameters of 90 mm and 70 mm. The technology controls the thickness of the three rubber layers and allows for adhesion without the use of air. The plant comes complete with cooling, transporting, cutting and vulcanisation units. Its automated features ensure constancy and repeatability of the process.
Solutions for recycling tyres ITS will present the ITS170/67 granulator installed as part of a complete tyre recycling facility in Poland that has an output of 25,000 tonnes/year. Driven by a 160 kW electric motor connected via V belts to a large flywheel, the grinder is able to process 2,000 kg/hour of 20 mm pre-shredded automotive tyres, shredding them down to a size of 5 mm. Compared to conventional blade granulators, the model’s staggered rotor blade geometry offers a smooth and gradual cutting action, requiring low energy consumption.
Once the recycling process is finished, a portion of the product is selected by a sieving system that subdivides it into various particle sizes to obtain batches with uniform granular consistency. The materials can be processed down to 0.08 mm depending on the application. The ground rubber is used in road surfacing as part of the asphalt mix;production of furniture and anti-shock pavements used in children’s playgrounds; running tracks and sports courts and in the manufacture of soundproofing and anti-vibration panels for the construction industry.
Recycling rubber through devulcanisation could be a cost-effective solution and this will be stressed by Maris as it presents a process that devulcanises rubber using a co-rotating twin-screw extruder. The thermo-mechanical process does not require the use of chemical agents and prevents material wastage. In terms of costs savings, devulcanisation breaks the crosslinks between the polymeric chains of the rubber,turning its characteristics similar to that of virgin rubber,which can be reintroduced in the production process. Users can save on new raw materials with this process, says Maris.
Dosing system and cranes for the rubber industry TO speed up the preparation of accelerator bags and additive products in under 1 bag/minute, Colour Service will introduce its automatic dosing system for powder and components for rubber compounds. The modular system has a double line of silos that incorporate the irrigation devices. Weighing is done directly on load cells to detect the weight accurately. The dispensing is moved step by step and run in a loop with a translator moving every keg from one row of silos to the next.
The compact system’s main feature is the simultaneous dispensing of all the products. This is accomplished since every silo corresponds to an independent load cell. Each bag will contain an individual recipe including all the products for that recipe dispensed together, ready for compounding. This enables the machine to reach the one bag per minute benchmark.
Applying its experience in the aviation industry to the rubber sector, Gruniverpal Tranchero will present its GB mobile cranes, complete with rotating boom, applicable to facilities with restricted movement. Available in a compact size of 1,400 x 800 mm and equipped with wireless remote control, the large crane can support up to 750 kg while its Minidrel S series can support up to 25 kg. The crane’s battery, remote control and hydraulic system provide control by preventing fluctuations from happening during the handling of moulds. The machine comes with a wide range of accessories and is designed for the tyre industry.
Range of injection moulding machines Injection moulding machine maker Presma will introduce its robotised island for the production of automotive parts. The solution covers different production phases from pressing to the finished product and is specifically used to draw, trim and fit simultaneously 64 rubber caps on corresponding plastic inserts.
The machine brings several advantages such as reduced time for item removal, manual labour, opening mould time,machine downtime and elimination of undue cycle stops.The latter improves the quality and consistency of moulded items by preventing the mould from cooling off and/or the compound from curing in the injection pot and extruder,which may change the physical chemical properties of the moulded times.
Another machine maker RPM will exhibit its Ecotronic electric press, said to halve energy consumption, reduce cycle time by 20% and render 30% higher output due to the patented Ecopower control for the clamping and injection.The patented screw and barrel control is said to reduce material wastage by 8%. A 7 kW electronic motor allows the machine to double the pressure and triple the speed during clamping and injection performance. Other benefits include lower downtime and oil-free finish of moulded parts.HT Mir Group and Wave Italia will present a range of horizontal machines such as the 450-tonne two-platen Mir HMPC with a torque motor. Available in clamping forces from 450-9,600 tonnes, the firm is currently developing1,200, 1,600 and 3,000 tonne-machines for the garden and automotive sectors at its facility in Brescia. Other new machinery from the group include the all-electric420-tonne Wave 420 E with the SERS (Saving Energy Recovery System) that offers energy savings of up to 20%and 420-tonne Mir HMG W with a large stroke for rubber processing. The firm says it is the only Italian manufacturer able to offer complete working stations (the production process is entirely made within the group) and supply turnkey plants including the press, automation, moulds, packaging, IML and other ancillary services.
Rubber compression press maker ATR has expanded its product range with a series of injection presses, one of which will be presented at the show. The 220-tonne press features a new clamping unit and a small footprint.In addition, the rear loading system has been simplified,allowing for several machines to be placed side-by-sidewhere space is a constraint. The press offers displacement of the moving platen, with an external extractor and an intermediate frame. Optional extras include the vacuum chamber and the magnetic anchoring of the mould.