Marangoni Unveils Ring Modular System
A few months ago Marangoni, one of Europe’s leading retreading systems providers, finally received the patent for its latest ring building technology, the best part of a decade after this technology first went into development. With the patent in hand, the Italian company recently invited journalists to see its RMS (Ring Modular System) technology in action. For Marangoni RMS represents the latest evolution in tread ring and retreaded tyre building technology, utilising an advanced level of automation. As a result Marangoni claims that the new machinery saves space, and completes the process in 30 per cent less time, consequently saving money on heat and electricity.
Before the Alpha Ring was invented treads were basically 50 metre long strips of green rubber that were manually placed in presses. Now a continuous strip of green rubber is automatically loaded onto a moving carriage, featuring an extruder and built-in calender that extrudes it directly into the centripetal press. At the end of the operation the applicator retracts and the extruder carriage moves to the next press, while the press closes. The equipment is arranged in a series of either 6 or 12 presses, depending on the size of the production line.
A typical Alpha Ring station of six presses served by one moving extruder is reportedly equivalent to nine traditional presses. There are also benefits in terms of flexibility. Previously each press processed the same product until the mould was changed. Now the 6 or 12 presses can each process a different product and deliver a different ring to the subsequent finishing station.
Next each ring is automatically identified by the system and blades remove the mould flash on the circumference. Radial trimming is then performed using a sophisticated “artificial vision system,” which is still in the development stage. This checks for defects in the tread, ultimately accepting or rejecting the ring. The subsequent brushing phase results in the rings being packaged in shrink wrap before being automatically labelled and palletised.
It is important to stress how the entire production process, from extrusion to packaging, is completely automated. According to the company representatives T&A spoke to, the new technology is nothing short of a milestone in retreading with makes “cap and base technology” a reality and takes retread quality one step closer to that of a new tyre.
Speaking to other Marangoni executives also revealed that the RMS technology is already in use on a 12 press line at Marangoni’s Madison, Tennessee plant in the US and on a 6 press line at the company’s Ellerbrock plant in Hamburg, Germany.
The RMS has benefits for the tyre building procedure as well. In this case, the company’s specific objective was the development of an integrated system for the selection, preparation and building of the tyres. And by this Marangoni means it aims to keep the installation in the smallest area possible, with no need for storage between the various processing phases.
In the initial building phase of the RMS production line, a new machine performs the complete inspection of the tyre. This shearographic system removes the need to turn the casings over, bringing significant advantages in terms of processing time, operating costs and assessment quality. Next the casing is passed onto a CNC machine for buffing. This acquires the measurements from the previous machine, makes the required settings automatically and then processes the casing, which is automatically coupled to a spindle. At the end of the working cycle, the buffed casing is sent to the following process, that is, the tyre building phase.
The building phase is controlled by the Ring Builder 3000, which essentially consists of an extruder for cushion gum, coupled to a Ring Treader with double building spindle. The double spindle allows two operations to run in parallel. In one position the cushion gum is extruded as a layer directly onto the casing, in the other position the ring is applied and suitably rolled. According to Marangoni, the high productivity of the Ring Builder 3000 makes it ideal for large retreading businesses. For smaller production requirements, the Ring Builder 2500 version is available, featuring identical measurement and control systems, yet with a single rather than a double spindle.
At this stage, then, the retreaded tyre production cycle ends with autoclave curing: an operation that, to ensure the best results, must be carried out in a vacuum. The retreaded tyre is then enclosed in special rubber envelopes; this is a tried-and-tested procedure that has not been further perfected by the RMS.