A leading tyre retreading firm is enjoying significant increases in energy saving, productivity and uptime thanks to drives from Control Techniques. 

Bandag, based in Johannesburg, South Africa, specialises in giving new life to truck tyres, enabling them to perform like new but at a fraction of the cost. It focuses mainly on truck fleets; new treads are applied to existing tyres to deliver more mileage over any terrain, using advanced compounds that resist wear and tear. Worldwide, around nine million truck and bus tyres are fitted with Bandag retreads annually. 

Bandag's manufacturing facility comprises various multifaceted operations starting from processing raw material, right through to extruding, pressing, finishing, trimming, quality control, and eventually warehousing. 

First in the operation line is the mixer – an enclosed automated mixing machine - that breaks down rubber and other constituents into working compound batches of approximately 220kg — an energy-intensive mechanical operation requiring consistent speeds and considerable force.

For a plant of this nature to run efficiently, it is essential to continuously look for new ways to improve the use of resources and decrease downtime, using ever-evolving industrial technology. 

This was Bandag’s aim as it looked to maximise the motor performance and the system reliability of the mixer, that previously used analogue DC drives, which became increasingly unreliable. 

Bandag then switched to Control Techniques' Mentor MP digital DC drives – locally distributed by Nidec SA. Having previously installed Control Techniques AC drives on the plant's extruder and Calendar Mill (a process that forms the exudates and processes cushion gum), Jim Fraser from Multispeed Transmissions, a trusted partner of Control Techniques, concluded that the mixer operation would also benefit from a similar installation. 

Jonathan David, Bandag SA Manufacturing Director, said; "Jim came to us with this idea, and we couldn't fault it. We had seen great success with the previous installations on the extruder and Calendar Mill, and it was a simple decision to roll this out to the mixer."

Bruce Grobler, Region Leader for Control Techniques, added; "We were delighted that Jim decided once again to fit Control Techniques' drives in this plant. Our innovative and reliable technology had proven itself in similar operations, positioning our high-performance drives as the go-to solution for this application." 

The Unidrive M700 AC was selected. A high-performance motor control system that provides ultimate control flexibility in high specification industrial applications. Two Unidrive M700's are now connected to a common gearbox, which evenly shares the load throughout the operation.

Bruce Grobler adds, "There are various aspects of this project that stand out. Most significantly, it involved a world-first for Control Techniques, which we were very proud to be part of. At the time of installation, this intermeshing mixer was the biggest tangential drive that Control Techniques had completed."

"The biggest worldwide tandem drive system at the time was 500 kW. At the Bandag plant, we had two of 1 MW each. This illustrates Multispeed Transmissions' appetite for a challenge and Control Techniques' high-performance drives and makes it clear why Bandag SA has continued to choose them over the competition." 

Jonathan David comments: "We were the guinea pigs! In addition to the actual technological solution, one thing that has contributed to the success of this project is that it has gone far beyond installation. Throughout operation, Jim and his team are at hand to assist us with the support of Bruce and Control Techniques. In the case of an issue, we can call Jim, who ensures that someone is onsite to assist us that very day, with spare parts at hand from Control Techniques. No excuses made. Spare parts are available when we need them, so that if a breakdown does occur, we get running as soon as possible."

"Not only is this convenient, but it saves space and money spent on warehousing as well as carrying the spares. For 20 years, we have trusted Jim, and we will continue with this professional relationship into the future."

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