Talk about reliability in manufacturing and the word that probably springs to mind is “motor.” Certainly, motors and other rotating equipment must be kept moving. No work is done unless a motor turns. Not surprisingly, suppliers have invested in technology to improve the reliability of these workhorses of manufacturing. Other parts of the automation system have gone under the reliability microscope, as well. As automation becomes more software intensive, it is imperative that engineers pay attention to reducing computer down-time. From sensors to software, engineers have used their ingenuity and technology to create a dependable automation system.

How about avoiding emergency shutdowns and saving your company $300,000? One paper plant invested in technology that monitors rotating equipment. The result was avoiding an emergency shut down, saving $180,000 in lost production and replacement parts, and another $120,000 on “machine clothing (Fourdranier Wire—a belt of woven wire used on the wet end of a Fourdrinier Machine, which is used to form a web of paper.).”

Typing and copy paper is made on very large and complicated machine trains comprised of dryers, siphons, motors, ventilation systems and a wide range of rolls, drives and webs. These machines produce paper at 3,200 feet per minute, and operate in a hot, wet, dirty and dusty environment. They require downtime every six weeks for adjustment, cleaning and replacement of worn parts and critical components.

Capacity on these machines means a loss of $15,000 an hour if an unexpected machine fault requires a shutdown. “An emergency unscheduled outage to change one of these rolls will cost us at least 12 hours,” says the plant’s fine paper machines Vibration Analyst. “That’s just the downtime, not counting a messed-up journal, bringing repair people in, and ordering emergency replacement parts.”

Constantly checking

Tending the machines is a constant job. Vibration monitoring with the CSI 2130 Machinery Health Analyzer and analysis with the AMS Suite Machinery Health Manager from Emerson Process Management, an Austin, Texas, technology supplier, for each of the fine paper machines at this plant is scheduled monthly, but sometimes even that is not enough. So the company added a CSI 4500 Machinery Health Monitor for continuous monitoring.

As the Emerson team was testing network connections for the installation prior to commissioning on the machine, an inner race bearing fault was detected on the breast roll in the Fourdrinier section of the machine. The expert vibration analyst verified the fault with the CSI 2130 portable analyzer. “The pattern showed up plain as day.” The roll wasn’t due to be checked again until after the scheduled outage. This would have triggered an unscheduled shutdown. Instead, repairs were made during the planned outage and no production time was lost.

The Emerson system saved the company $180,000 in production and $120,000 in machine clothing replacement before it was even commissioned. This plant now has 46 CSI 4500 Machinery Monitors keeping track of about 600 sensors on hundreds of rolls turning from 160 revolutions per minute (rpm) up to 2000 rpm on each fine paper machine. The monitors continue to prove their value.

Adding sophisticated sensors and the analysis tools to gather and interpret the data is seen as a growing competitive advantage—and not just in process automation such as the paper plant just discussed. “In this more competitive environment, even automotive companies are starting to look at reliability, predictive maintenance and condition monitoring as a competitive advantage,” notes Preston Johnson, segment manager for the sound and vibration team at National Instruments Corp. (NI), the Austin, Texas, supplier of data acquisition and automation technology.

Johnson relates a story about an NI systems integrator in Michigan who repairs robots for automotive customers. It built a database of information collected from customers to help them reduce repair time. The integrator worked with NI to put sensors on robots in order to enhance the data acquisition by monitoring repair points. Many of the robots and conveyors needed parts monitored in hard-to-reach places, making remote data acquisition more beneficial than depending upon manual inspection.

Best sensors

Steve Garbrecht, director of product marketing at Wonderware, an Invensys-owned software supplier located in Lake Forest, Calif., maintains that the best sensors in a plant are not connected to any control or database. “You might have 20 to 40 people in a plant on a human-machine interface (HMI) terminal sharing information with each other and the system,” he says, “but there may be another 600 people who don’t use computers as part of their jobs. They are walking around the plant ...