By by Mike Bacidore, Managing Editor
A Harley-Davidson motorcycle epitomizes untethered freedom.
So, it made perfect sense when Dana Fluet, maintenance reliability engineer at the H-D machining center for motorcycle power trains in Milwaukee, decided to make the plant’s vibration measurements wireless.
The facility, which cuts engine- and transmission-related parts, has been using walk-around vibration analyzers in the past, but that technology can create production obstacles. “We have a walk-around vibration program,” says Fluet. “But we have to take a machine out of production, run it at a fixed speed and take measurements. Plus, we’re not running the spindle under load. Conditions will vary under load versus under no load. Those were the two obstacles we had to overcome—not interrupt production and collect data while the spindle was cutting or under load.”
With more than 1,400 assets under one roof, Fluet has a lot of machines and processes to monitor via walk-around. He’d like to implement wireless monitoring throughout the H-D plant, but you have to walk before you can ride.
Emerson Process Management’s CSI data collectors are used to collect data around the plant from a variety of brands of vibration sensors. “Right now, the third phase of a Techkor wireless solution supplements these,” says Fluet.
The power-train plant has multi-axis machine tools or CNCs, some with as many as six axes. “We can’t hardwire the existing machines,” explains Fluet. “I was looking for a wireless technology that we could attach to a spindle inside the machine and continue to run the machine while monitoring the condition of the spindle bearings. It’s difficult to get data out of the nose with wires hanging out (Figure 1). It’s difficult to support cables in these.”
The important feature Fluet wanted was vibration monitoring. “I need to identify the bearing fault and plan replacement,” he says. “We have 60 tools, and each tool runs at a different speed. When we set a schedule, we don’t know which speed it’s running at.”
Ultimately it was the solution’s nature and the bottom line that prompted Fluet to look for sensors that were completely wireless. “These sensors are mounted on each machine and subjected to direct coolant spray during machine operation,” says Bob Kirker, sales manager, Techkor Instrumentation, of the harsh environment. “And Fluet’s putting these sensors in metal enclosures. From a wireless perspective, that’s a difficult environment.”
In most cases, each machine has one sensor, explains Fluet. “Our R&D project is using one sensor per machine, too,” he says. “One machine has six sensors because it has six spindles. Two Cisco repeaters with a 250-ft range are interfaced with Techkor network access points, which are also good to 250 ft from the sensors, giving a total package of 500 ft. In the end, when you add in the cost of routing cable and connection, it’s more cost-effective to install wireless.” Many wireless sensor solutions are actually tethered, with an accelerometer connected to a junction box, says Kirker.
Cost savings already have paid dividends for Fluet. During Phase II, the wireless sensors captured data when a machine started to lose a spindle bearing. “We were able to replace the spindle without losing production,” he says. That financial impact enabled him to fund the addition of more sensors.
“My dream is to have these deployed on many, many machine tools so we can monitor everything,” says Fluet. “We have around 350 A-critical machines.” If an A-critical machine is down for more than four hours, it impacts the assembly line and consequently the H-D facilities in York, Pa., and Kansas City, Mo., where completed power trains are delivered. “I want all 350 of those A-critical machines wirelessly monitored,” he says.
Back to School
Pivotal to Fluet’s aspirations is the Center for Intelligent Maintenance Systems, directed by professors from University of Cincinnati, University of Michigan and Missouri University of Science and Technology. The Center for IMS is an NSF industry/university cooperative research center that works on projects with more than 50 member companies to transform the traditional fail-and-fix maintenance practice to a predict-and-prevent methodology. As a member company, H-D has access to IMS university graduate students who can help with R&D, as well as IMS’s Watchdog Agent prognostic tools. Dr. Jay Lee is the director of the Center for IMS.
“We’ve been working with Dr. Lee at the University of Cincinnati,” explains Fluet. “He’s got a handful of master’s and Ph.D. candidates in mechanical engineering. I’ve been using one of their students to integrate the Techkor wireless system on our machine tools using Watchdog Agent, the integration device from the University of Cincinnati.”
Ultimately, the goal is to integrate sensor data with the control system on the machine, so it could shut down the machine when an anomaly occurs. “The Watchdog Agent will provide that capability,” says Fluet. “It will interface with a Siemens or Fanuc controller, which are the primary ones we use on our machine tools.”
Getting There Is Half the Fun
While Fluet began his wireless trip with a destination in mind, he wasn’t quite sure how to get there until he found Techkor. “He had the concept in mind,” explains Kirker. “He took our existing system, which got him to 80% of where he wanted to go and deployed it across his factory for about a year and figured out the capabilities. Then he came back to us and asked if we could help him with polling. He was looking for more consistent data to trend with. He hooked us up with the Center for IMS, which has the PLC interface that we don’t have. That opens a lot more opportunities on the control side of things.”