Rockwell Automation has broken new ground in South Africa’s rubber industry, with the supply of the company’s flagship medium voltage variable speed drives, the PowerFlex 7000, to Sumitomo Rubber South Africa’s rubber mixing lines at its Ladysmith plant.
The rubber mixing lines require exact adherence to the relevant recipes of the rubber mixing processes to achieve a usable end product. The addition of two new medium voltage drive systems further complements the large install-base of Rockwell Automation low voltage PowerFlex variable speed drives and ControlLogix PLC systems already installed and integrated. “Roughly 60% of the automation infrastructure for the Ladysmith plant consists of Rockwell Automation products,” according to Udaiyappan Ulagappan, Factory Director, Sumitomo Rubber South Africa (Pty) Ltd.
Smart systems for complex process control
To meet the high demand from both domestic and regional markets, the tyre manufacturer must continuously produce high-quality products that are delivered on time. Downtime in the tyre manufacturing process must be minimised to prevent significant losses in production and delays in delivery.
In addition, greater demands on tyre performance requirements have increased the complexity of the rubber mixing process, with several individual processes fully integrated with modern control technology.
The tyre manufacturing process begins with the mixing of ingredients necessary to make different types of rubber for different kinds of tyres the plant produces. A Banbury mixing machine combines basic rubbers with process oils, carbon black, pigments, antioxidants and other additives, each contributing certain properties to the compound.
Operating under high temperatures, the ingredients are blended to create a black gummy compound which is milled several times before forming and curing is done. To achieve the correct compound, accurate speed control is required, as a change in speed has an impact on how the ingredients are mixed, which impacts the elasticity of the compound.
“Parameters such as temperature, consumed power and duration all need to be precisely controlled in an application exerting a harsh load profile,” explains Jacques Lottering, Power Control Account Manager, Rockwell Automation Sub-Saharan Africa. “The solution was engineered according to our client’s specific load profile, the mechanical system data as well as the expected impact on the electrical system.” Third-party kWh counters were integrated in the PowerFlex 7000 drives during manufacture, taking advantage of the company’s open-source automation topology and Ethernet protocol.
This drive system was designed in collaboration with electro-mechanical equipment manufacturer ACTOM. The Rockwell Automation PowerFlex 7000, in combination with ACTOM’s motors, has now become the standard for all future mixers commissioned by Sumitomo Rubber South Africa.
“Rockwell Automation worked closely with Sumitomo process engineers in both South Africa and Japan to engineer a solution that achieves complex process control functionality through high-tech, energy-efficient drive systems,” Bhardava explains.
Phase Two of the project will include new mixer lines which will enable Sumitomo Rubber to meet the increasing demand from vehicle manufacturers for its numerous tyre brands
The Industry 4.0-ready Allen-Bradley PowerFlex 7000 Medium Voltage AC Drive is an air- or liquid-cooled general-purpose, stand-alone drive for controlling speed, torque, direction, starting and stopping of standard synchronous or asynchronous AC motors from 150 to 25 400 kW.
About Rockwell Automation
Rockwell Automation Inc. (NYSE: ROK), the world’s largest company dedicated to industrial automation and information, makes its customers more productive and the world more sustainable. Headquartered in Milwaukee, Wis., Rockwell Automation employs approximately 22,000 people serving customers in more than 80 countries.
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