GROVE CITY, Pa. — As diesel locomotive engines are being manufactured outside its doors, a quiet lab, no bigger than a small store, in a corner of the Wabtec factory in Grove City is magically creating industrial components from powdered stainless steel using lasers. Asked if this is leading-edge technology, the lab’s chief, Jennifer Coyne, replies, “No … it’s bleeding-edge technology.”
Commonly known as 3D printing, which in its simplest form can be done at home with printers costing just a few hundred dollars, industrial-scale additive manufacturing – so called because items are built one microthin layer at a time – has to date largely been confined to the aviation, aerospace, automotive, and health care industries.
Wabtec, which acquired the Grove City facility from its merger with GE Transportation, is bringing this advanced technology to the railroad industry, where it has the potential to replace casting and forging for some industrial components.
Recently, the lab helped get a customer’s prime mover, in for overhaul, back in service quickly when needed cast pieces weren’t delivered from the supplier on time. “We were able to print them, so they can build the engine and not miss the date,” says Coyne.
She has worked on railroad technology for 12 years, mostly tackling things like adhesion systems for locomotives. Two years ago, Coyne took on the role of additive manufacturing leader. “It’s really neat to bring new technology into a relatively old industry,” she says.
Trains News Wire was given an exclusive, first look at that technology during a tour of the lab, which is still coming together, with three additional machines due in December.
The high-ceilinged, white-walled space is clean and quiet, with test parts and prototype components scattered along small shelves. In one corner stands a tall gray cabinet that contains a curing oven. A glass booth, about the size of a large walk-in closet, houses an industrial-level 3D printer for classic polymer-based printing.
Wabtec is now pioneering two sophisticated metal-printing processes.
In the first, a direct metal laser melting machine deposits a fine metal powder layer by layer, building up a three-dimensional object, often requiring thousands of passes. Instructions are sent from a design computer. It’s a slow process, says Coyne, but works well for prototyping, low-volume output or highly complex parts. “In this process, we get really good first-pass yield,” she explains. Finishing requires the removal of excess powder (which can be reused), cutting the component from the build plate, removing any support structures, and final machining.
At times, they’ll come across an out-of-production part that needs replacing. Using a 3D scanner, a laser precisely measures the existing component and the resulting computer model is used to recreate the part.
That can help keep older locomotives on the road, saving replacement costs. 3D printing has also demonstrated its ability to keep vintage aircraft flying and could find applications in the restoration of historic railroad equipment.
A second process breaking new ground is direct metal-jet binding. Instead of using lasers to build up each layer, an inkjet printhead deposits tiny drops of a binding agent onto a bed of metal powder, essentially gluing the object together.
“We’re one of just a few beta customers that own this machine and one of the first develop to it out,” Coyne reveals.
The piece, called a green part, is then sent to the curing oven to evaporate away the glue. From there, it moves to a high-temperature sintering oven. At 2,500 degrees Fahrenheit, just below the melting point of stainless steel, the metal becomes fused to its final form.