Tyre manufacturer Bridgestone South Africa hosted a media tour of its 186 027 m2 manufacturing facility in Brits, the North West, in July to showcase how its technology had evolved from the 1950s to date.

Bridgestone manufactures passenger radial, light truck radial, truck and bus radial, and run-flat tyres at the Brits facility as a qualified original-equipment supplier to automotive brands such as BMW, Mercedes-Benz, Toyota, Volkswagen, Isuzu, Nissan and Ford.

The Brits plant produces about 5 550 passenger tyres a day, and goes through 1 700 raw rubber tons a month across the product portfolio, according to Bridgestone South Africa manufacturing executive manager Ian Marsh.

Additionally, Bridgestone manufactures light truck bias, truck and bus bias, agricultural bias, and off-road bias tyres, as well as precured tread for retreading tyres, at its manufacturing facility in Port Elizabeth, in the Eastern Cape.

The Brits plant is one of six globally in the Bridgestone group manufacturing run-flat tyres, which is tyre technology that allows a vehicle to keep driving for 80 km at 80 km/h even when air loss or a puncture is detected, eliminating the need to stop and change a tyre, while contributing to a saving in materials, since spare tyres are not necessary.

Conventional tyres use pressurised air to support the weight of the vehicle. However, when the tyre is punctured, air escapes and the weight of the vehicle is no longer supported. This results in a flat tyre.

When a run-flat tyre is punctured, it loses air, but it continues to support the vehicle’s weight using the reinforced sidewalls.

Bridgestone also has eight retread factories across the country and in Namibia, where truck and bus radial casings can be retread.

Meanwhile, there is continuous demand for low-rolling-resistance tyres from original-equipment manufacturers and suppliers. Consequently, Bridgestone South Africa manufacturing renewal executive Dries Lottering explained, the company regularly upgraded the Brits facility’s equipment to be able to produce this type of tyre.

In line with facility renewals and upgrades, Bridgestone recently started implementing the integrated work system (IWS) methodology at its factory, where a bottom-up management process is used, whereby employees take charge as equipment decision-makers, rather than executives, who do not encounter the machinery as often, if at all.

The Brits facility employs 801 people.

Lottering said the IWS had improved Bridgestone’s productivity to lower defect levels and quicker shift changeovers.

The Brits plant manufacturing process comprises a raw materials section, where natural rubber or synthetic rubber, as well as additives such as carbon black, is stored. The first step is the compound mixing of the raw materials, and then extrusion.

Thereafter, the process moves to component preparation, which entails steel cord calendaring or fabric calendaring, tyre building, curing and, finally, quality checking and inspection.

For the compound mixing process, Bridgestone is in the process of upgrading to Variable Intermesh Clearance Mixing technology, which offers better heat distribution and enables low rolling resistance, while saving energy and delivering a higher-quality compound.

“The strength of the intermeshing design is in its ability to move materials aggressively within the mixing chamber, effectively shearing the mix and, owing to its surface-area-to- volume ratio design characteristics, an enhanced ability to remove heat generated during the mixing process is achieved,” explained Bridgestone South Africa operations GM Barry Nigrini.

He noted that Bridgestone South Africa was busy preparing the Brits plant to introduce new steel calendaring technology, which would cut steel wires even thinner than with existing technology. These machines would be operational by 2020.

The steel within the tyre offers extra resistance and resilience, which is more often used in truck and bus tyres than passenger tyres. For fabric calendaring, the company prefers using polyester and rayon fabrics.

For quality checking and inspection, the plant uses X-ray machines to check the inside of the tyre for any defects.

Lottering concluded that the Bridgestone South Africa plants underwent continual renewals and upgrades to keep up with customer satisfaction standards and original-equipment manufacturer demands.