HIGH-TECH OVERHAUL SHOP: ROBOTS PEEN, PLATE & PLASMA SPRAY
Engine overhaul 4.0 begins here. P&WC Engine Services is a next-generation aircraft repair shop, deploying robots and state-of-the-art systems to achieve unprecedented precision, quality and speed.
These words conjure up images of workers in grimy overalls banging away with tools in a shop covered in grease. Nothing could be further from the reality at P&WC Engine Services in Bridgeport, West Virginia.
This P&WC Engine Services shop—which handles general repairs and overhauls for the PT6A, JT15D, PW300 and PW500 families—has embraced a new world of repair technology, investing in a formidable arsenal of technologies that includes an automated peening system, a full-capability plating line, plasma spray technology and X-ray technology. All of these reduce turnaround times and increase the precision of repairs and overhauls.
Peening is a process that blasts the surface of a part with glass or steel to apply compressive stress. For engine parts, this stress is good, because it helps them better endure tensile stress—which leads to expansion—during operation. The use of computer numerical controlled (CNC) robots for peening ensures precision, as robots are able to perform tasks with far greater repeatability than their human counterparts.
“Tensile stresses can be detrimental to the life of a part,” notes Mark Dettori, Senior Engineer, Repair Processes. “We apply compressive stress with peening to offset it and increase the part’s fatigue life. It also improves adhesion when you apply coating.”
In the past, nearly a thousand parts had to be sent out for peening every year, taking time and increasing costs. “The more times critical rotating components are handled, the more prone they are to damage,” explains Jeffrey Powell, Business Development Manager. P&WC Engine Services is now able to do the work in-house, limiting the risk of accidental damage while cutting out shipping and other outsourcing costs.
“We’ve probably cut the cost in half by reducing the per-hour rate, plus saving on the cost of shipping the part to an outside vendor,” says Mark. “We’ve also come up with a system in collaboration with a partner that reduces the cost of the fixtures used to hold parts during peening.”
Technologies are among the ways we maintain a competitive edge while supporting operators’ business by making repairs faster and more cost-effective.
"You always have to look ahead five to ten years,” Tom Rhine, Manager, Logistics & Component Repair Business, told Airtime. “In the case of peening, we decided to get into it about five to six years ago because we saw a growing need and opportunity to better serve customers.”
PLATING TAILORED TO AVIATION
A full-range plating line, which may be used, for instance, to apply nickel or chrome plating to worn parts in order to bring them back to their original blueprint dimensions, or to apply protective coatings such as cadmium or silver, gives P&WC Engine Services a definite edge.
“There are only a few repair and overhaul shops that offer a 100% range of plating capabilities, and we’re one of them. We’ve got world-class plating facilities for any kind of P&WC engine,” notes Jeffrey.
“Any plating that might be needed, we do in-house,” adds David Slakes, Project Engineer, Aftermarket Repair. “That’s a very special situation for a repair and overhaul shop. Plating shops tend not to specialize in aviation, and if you do send parts to one, you’re often at the mercy of their schedule, because they’re rare and in high demand.”
Plating is very specialized and strictly regulated. It requires an enormous amount of investment to get up and running, and you need a specialized wastewater treatment system. We’ve been investing in it for decades. The water that goes out is better than the water that comes in.
HIGH-PRECISION PLASMA SPRAYING AND MORE
Plasma spraying leverages robotics to provide greater precision and repeatability. Similar to plating, it may be used to coat worn engine parts by using temperatures as high as 5,000°C to melt coating materials then spray them onto components with a large compressor, chiller and high-voltage power console. Powders are injected into the plasma stream axially, accelerating them to an extremely high velocity.
The facility also offers X-ray technology for examining the quality of welds and a CMM (coordinate measuring machine) for dimensional inspection.
EACH COMPONENT IS UNIQUE
Engines are like snowflakes: each one is unique. As Jeffrey explained to Airtime, “Every engine that comes in to our shop is different, depending on the type, how long it’s been in use, its operating environment and so on. In the 30 years I’ve been here, I doubt that we’ve ever done exactly the same engine repair twice."
Thanks to the use of new technologies, we’ve considerably reduced the turnaround time for the engine overhaul process, which is a major advantage.
Given the highly sensitive components that P&WC deals with, including rotating compressor components like integrally bladed rotors, impellers and fan blades, each component must be considered individually.
TAT—or "turnaround time" —is a key metric for P&WC. “TAT is a big deal for our customers, because they want their engine downtime to be as short as possible, predictable and on schedule,” notes Mark.
Repair and overhaul technologies are just one of the fields where P&WC and its partners are pushing the envelope. Other innovations covered in Airtime include remote borescope inspections, Oil Analysis Technology and sustainable business practices.