ideal torque and current signatures for standard testing routines for evaluating the performance of one of its machines.

When the machine is down for routine maintenance, one of the user’s maintenance technicians can run it through the same routine and compare the new signatures with original data to determine whether the axes are too stiff or have too much play in them. The results then can be uploaded into Microsoft Excel or other software on any personal computer (PC). The HMI on a PC-based computer numerical controller (CNC) running the machine can display the results locally, or the technician can send the file through the Ethernet network connection to the factory enterprise system so an engineer can retrieve and analyze it. If the discrepancies between the ideal and actual are large enough, the technician or engineer can submit a repair order.

In some applications, such requests go directly over the network to the maintenance office, using software available for this purpose. CL Automation’s monitoring software, for example, receives such alerts, schedules downtime, tracks corrective actions and generates reports. “We set up an intranet application that can be broadcast throughout the corporation,” says Nichols. “One company even sends a page to the maintenance department, so technicians actually get an audible sound alerting them that they need to address a problem.” Others that have service contracts with equipment builders or third parties transmit the messages over the Internet or other network.

To close the information loop, some users install identification-card readers on the machines. As maintenance technicians answer calls and make the necessary repairs, they swipe their cards through the readers to turn off the alert messages and to update the maintenance log.

Good for business

Users who are backing the research in intelligent predictive maintenance and buying the supporting technology tend to be those who look at the value of equipment to the enterprise over its lifetime, rather than just the up-front costs. No matter how long the company plans to keep the equipment—whether it is three or 20 years—there is a specific cost to own it. Predictive and preventive maintenance programs can cut the cost to own by between 15 percent and 30 percent over the equipment’s lifetime, according to CL Automation.

The lower costs come from greater mean times to repair and greater mean times between failures. “Once you establish a plan for predictive maintenance, you’re able to schedule maintenance at a planned time,” explains Nichols. “A planned scenario gives you the ability to prevent unplanned downtime.” Moreover, when an expected problem does occur, the technology can give the maintenance supervisor a good idea of what is wrong before dispatching a technician, allowing the technician to arrive prepared to solve the problem and get the machine running sooner than would be possible otherwise.

Fewer unexpected repairs and less unscheduled downtime make manufacturing much more predictable, which offers businesses a number of other benefits. For example, manufacturers can set operating budgets and to stick to them. They can carry smaller inventories of spare parts, ordering many parts as they need them. Moreover, greater predictability helps factories to keep production schedules and make promised deliveries to their customers.

Reaping these benefits, however, requires more than simply having a predictive maintenance plan. It demands action. Users cannot be like a driver who ignores the change-oil light on the dashboard when it comes on. “When you get the alert, you have to do the required maintenance,” urges Jeff Anderson, service manager at CL Automation. “That calls for management to be involved and to enforce compliance.”

Only then will it be able to maximize uptime and cut cost at the same time. “Rather than reactive maintenance—fail-and-fix—companies can indeed move to predict-and-prevent maintenance,” says Lee at the IMS Center.

For more information, search keywords “predictive maintenance” and “preventive maintenance” at www.automationworld.com.