Inspect moving parts with strobe lights

Strobe lamps enable operators to inspect moving parts.

Ponderay Newsprint Co. of Usk, Wash., meets its annual production of as many as 260,000 metric tons of newsprint using a single 330-in. trim Valmet twin-wire paper machine. To supply the partnership that formed Ponderay — between AbitibiBowater Inc. (Ponderay’s managing partner) and subsidiaries of five newspaper publishers — Perry Pearman, reliability engineer for Ponderay, says he wants to increase production reliability for a competitive advantage.

Beginning about three years ago, Pearman says, he was asked to build a program to address this issue. A major problem for reliability was, “How do you look at machinery that is moving rapidly and determine where there is failure before there is a breakdown?” The mill has many pumps, motors, belts, agitators, motor couplings and fans. Breakdown of even a single motor, pump or belt can shut down the entire football-field-sized machine.

Joel Hendershott, Ponderay operations technician 2 and described by Perry as the resident plant genius, was pulled into the project. Hendershott says he worked with machine operators to devise inspection routes, ensuring that “each piece of equipment is checked on a weekly basis.” This became the Operator-Driven Reliability Program. About 28 routes were developed to examine equipment from the basement to platforms above the machine.

A strobe light was used to provide a stop-action effect on the condition of moving parts. In an Internet search, Hendershott came across the ESL 10-A LED stroboscope by Hoto Instruments (www.hoto-instrument.com). “It was exactly what we needed — small, light and simple to use for on-the-run inspections with LEDs that don’t burn out,” he says. “It’s very easy to read on the run and it comes at a better price than other strobes. And the Hoto LED strobe fits into pouches, which leaves the operators’ hands free.” This is especially useful as operators climb up or down or into various areas to get a look at their assigned machinery.

To accommodate the strobe, belt and rotating shaft guards were modified with cutaways covered in black wire mesh. As operators direct the strobe on the moving parts, the dark mesh provides greater contrast for ease of viewing. This contrast makes, for example, grease stains thrown by loosening bolts more visible.

Pearman says, “The pushbutton speed control on the Hoto LED strobe is just what we needed. By pressing the button, operators can change the flash rate, highlighting different sections of a rotating shaft. Then they can see all sides of a coupling.”

By changing the strobe speed while inspecting a belt, “fraying, bad splices and missing chinks can be discovered before the belts fly apart,” Hendershott says.

Electricians or maintenance personnel provide a more expert opinion, as needed. For example, every 18 degrees of increased motor temperature decreases motor life by 50%. In the motor end bell is a fan that pushes cool air over the motor’s cooling fins. Pearman says, “Greg Vaughn, the mill electrical engineer, and I grabbed strobes to look at the motor end bell cooling systems.” While using the strobes to inspect the cleanliness of the fan blades, Perry and Greg were able find fan blades that were damaged or had broken off, which lead to premature motor failures.

The operator checks are part of an overall basic care and condition-monitoring program at Ponderay Newsprint Co. When a failure is noted, the operators generate red- or yellow-flagged repair orders and schedule repairs for the next outage. This data and data on conditions throughout the plant are shared with several mills in an effort to problem-solve within the industry rather than just within a single plant.

Hendershott says the LED strobes are critical for the initiative. “I don’t think the Operator-Driven Reliability Program would be working if we hadn’t been able to find the right strobes. The Hoto LED strobes make looking at our moving machinery a go."

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