Drive system for rubber mixers
1st Quarter 2018, Electrical switching & drive systems & components
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 factory director of Sumitomo Rubber South Africa, Udaiyappan Ulagappan.
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.
The ingredients are blended at high temperature to create a black gummy compound which is milled several times before forming and curing. 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 power control account manager, Jacques Lottering. “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, standalone drive for controlling speed, torque, direction, starting and stopping of standard synchronous or asynchronous AC motors from 150 to 25 400 kW.
For more information contact Michelle Junius, Rockwell Automation, +27 (0)11 654 9700, firstname.lastname@example.org, www.rockwellautomation.com