Century Aluminum, a global primary aluminium producer with operations in the United States and Iceland, has upgraded its aluminium casting equipment at its smelting plant in South Carolina. The plant boasts casting equipment capable of processing approximately 230,000 tonnes of aluminium annually, delivering standard-grade ingot, extrusion billet, and other products.
Image Source: Century Aluminum
However, as per reports, the two cooling tunnels were experiencing increased downtime due to outdated controls that had reached their functional limits. As a result, to tackle this challenge Sam Wilson, casthosue technician at Century Aluminum reached out to Miguel Ortiz, product manager at Electrical Equipment Company, a local Siemens distributor and technology solutions provider. Ortiz and his team at Outreach Resources assessed the situation and developed a tailored solution.
In its casting operations, the company uses cooling tunnels to lower the temperature of aluminium billets after homogenisation. These tunnels are designed to reduce billet temperatures from around 1,000°F to 90°F. The cooling unit features drives that regulate the main fans, ensuring a steady flow of cool air that circulates efficiently around the aluminium bundles.
"We were faced with an increase in downtime on our two cooling tunnels due to legacy controls that were getting beyond their functional limits," said Sam Wilson, casthosue technician at Century Aluminum. "The older drives would have required major rebuilding as they were able to track only speed, delivering the data to the PLC. We required more data and faster processing of it."
The upgrade involved retrofitting a competitor's drive with a Siemens SINAMICS G120 an Intelligent Operator Panel (IOP-2), and a specialised Remote I/O (RIO) to EtherNet/IP™ gateway, co-designed by Siemens and SoftPLC. This gateway was specifically created to facilitate a seamless transition from the legacy drives to the new system. Additionally, the upgraded setup now transmits valuable data, including current and torque, providing the customer with enhanced operational insights.
50% reduction in downtime & lots more
According to the team at Century Aluminum, the improvements led to a significant reduction in downtime of over 50 per cent, ensuring more reliable cooling of the aluminium materials. The additional electrical information transmitted allowed for better data analysis, while programs stored on the IOP-2 enabled quicker recovery.
"The plug-and-play technology plus the substantial program storage on the IOP-2 make our training of younger techs and operations personnel much easier. With the older equipment, line code upgrades were very time-consuming, while they're automatic on the Siemens equipment. The younger employees have that fast and easy modular mindset, which is great, as it matches the plug-and-play technology. Saves us a lot of time and money. I thankfully was on an old boat in the Navy and some old Los Angeles class submarines, so I know a bit more about the history of the legacy gear," noted Wilson.
The plug-and-play feature also eliminated the need for tools when wiring one drive to another, streamlining the implementation process. Wilson emphasised the importance of smooth changeovers since the cooling tunnels operate 24/7, 365 days a year. Thanks to the efficient design, both control cabinets were successfully completed within eight hours.
"One of the big advantages on this job is that we were able to take a demo unit into Mt. Holly and show Sam and his team how to configure the gateway without disconnecting the legacy PLC-5 controller. We could scale, readjust and map the start/stop activity, plus being able to install and test run the new equipment without changes to the PLC-5 controller program meant the system on the first retrofitted cooling tunnel were ready to roll much faster and at a lower overall cost," added Ortiz.
Now fully operational, the new Siemens control system has cut the cooling time for a 75-ton load in half, increasing daily processing capacity by 300,000 pounds. Additionally, the tunnel conveyor motors operate more efficiently in standard mode instead of dynamic mode, contributing to further energy savings. The 150 hp drives offer enhanced flexibility for Century's operations. They can also be repurposed for use at the company's carbon plant in Mt. Holly, where 75 hp motors are standard, providing an additional inventory advantage.
"In addition to the demo unit we used, about ten days prior to the install, we did an event at the customer's facility where we gathered the technicians and some of the engineers to give them an overview of the drives, the IOP-2 and how to troubleshoot from the TIA Portal software. The training gave them both practical knowledge and a higher comfort level, as the majority of those present had lots of experience with another brand of drive products. We were able to show them how to seamlessly connect the new and the remnant legacy products," commented Ortiz.
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