Marangoni has been able to demonstrate its technological prowess in the OTR sector recently thanks to a recent application of the company’s new MTXL retread in the Finnish market, according to Ayhan Haliloglou, OTR tyre Area Manager at Marangoni.
Marangoni’s New Solution for the OTR Segment
“Recently, a customer from Finland contacted us to request if we could design a new retread solution for the tyres mounted as original equipment on their Kiruna slag pot carriers,” explained Haliloglou. “These new premium tyres in size 29.5R29 had a newly designed casing with higher load capacity and a completely new tread design.”
The end-user was looking for a way to use these casings for a second life with a tread design similar to the original and in a manner suited to their specific needs: traction and cut/tear resistance – two fundamental features for the mining industry. Following this request, Marangoni started evaluating the development of a new product, keeping a constant, productive and meaningful dialogue with its distributor – Lujakumi Oy – and their customer – Valtasiirto Oy.
Lujakumi, whose headquarters are situated on Finland’s west coast, is one of the most experienced retread companies in Europe. The company was founded in 1954 and, since 2017, they’ve been using RINGTREAD System, Marangoni’s leading-edge technology for the retreading of truck and bus tyres. In 2018, they added Marangoni OTR retreads to their commercial offer, by signing a distribution agreement with the Italian firm.
Valtasiirto is a company specialised in delivering comprehensive solutions for industrial indoor and outdoor logistics, with business offices located in all the largest Finnish industrial parks. The firm was established in 1999 and, since then, they have offered a large variety of services including the management of the raw material stock for customers operating in the mining industry.
Markku Mäkipää, OTR Specialist at Lujakumi, claims that it became immediately clear that the end-user was looking for more than just a partner to fulfil their traditional tyre needs. “Besides retreading their standard wheel loader and articulated dumper tyres, Valtasiirto were also looking for an economical and ecological solution for their specialised pot carrier vehicles,” said Mäkipää. “Having successfully cooperated with Marangoni for several years, we knew that everything was in place to satisfy this request,” he added.
After starting the collaboration, the end-user experienced Marangoni’s retreading technology by making a fact-finding visit to Italy, according to Jori Huhtaniemi, Director of Maintenance at Valtasiirto. “After getting an in-depth tour of the Rovereto’s plant, we were really impressed by the high technology content implemented by Marangoni in their production process. This visit proved a great opportunity to gain a much greater knowledge of how premium quality retreading takes place,” he said.
As the specific operation of the tyres equipped on the front axle of their Kiruna slag pot carriers is very severe, and safety is the main priority, Marangoni proposed a rigorous casing inspection regime before committing to the development of a new product.
“The tyre size 29.5R29 had never been retreaded by Marangoni, so the initial analysis was critical,” explained Haliloglou. “After retrieving the customer’s casings, our operators checked the different parts of the tyres to ensure that the quality and casing integrity was acceptable for the retreading process.”
The next step was to remove the old tyre material by buffing to precise dimensions. The casing was then measured after buffing until the minimum required amount of base rubber remained. Further casing inspection was then carried out by the Marangoni operators. These tyres have been used in very demanding and arduous conditions, and several small damaged areas were detected. However, thanks to Marangoni’s extensive experience in tyre repairing, this posed no threat to the retreadability of the tyres.
After studying the application and machine schematics, Marangoni’s engineering and production departments proposed a tread depth, a pattern design and a tread compound that would fit this specific operation and be suitable to produce on this casing model. Once the exact specifications were determined, the production process continued.
“The building process is more advanced than most people think,” said Haliloglou. “Some people assume that a pre-cured tread is applied to the casing, but this is not the case. In fact, the OTR tyre is rebuilt from the casing on as if it was a new tyre. The casing is mounted on the building machine and starts to spin, while an extruder arm applies three different layers of compound – base, intermediate and tread evenly from shoulder to shoulder,” the area manager added.
During the inspection/measurement phase of the casing, it became apparent that this specific type of casing was not within the dimensional parameters of an L4 casing. Therefore, it wasn’t feasible to process the casing in a conventional hot-cure mould, and so it was decided to use an autoclave.
Marangoni’s Recaflex system allows the company to groove tread patterns in almost any way possible. “But before we could do that,” said Haliloglou, “we had to programme our software with a new design, optimised to meet the end user’s specific requirements.” After the computer programming, the tyre was mounted on the Recaflex machine and the equipment grooved the tyre accordingly.
Finally, Marangoni’s specialists inspected the product for any defects and imperfections. After the visual inspection, each tyre was inspected using a shearography machine.
The tyres have been recently shipped back to Finland, where they have been further inspected and mounted on one of the Valtasiirto’s slag pot carriers. Currently, the MTXL retreads are in operation and are being closely monitored by Lujakumi’s technical specialists, to prove that Marangoni OTR retreads are suitable for the toughest conditions of this severe industrial application.
