Pratt & Whitney deploys robot BARB at Connecticut plant to assemble geared turbofan engine bearings

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Pratt & Whitney Deploys First Assembly Robot at Connecticut Jet Engine Plant

During a recent tour of RTX-owned Pratt & Whitney's jet engine assembly plant in Middleton, Connecticut, TWZ observed that nearly everything was quiet on the production line following a major push to complete outstanding deliveries by the end of the second quarter on July 1. However, one machine remained calmly at work: the Bearing Automation Robotic Builder — known familiarly as BARB.

BARB was completing assembly processes for the #2, #5, and #6 bearings on the company's commercial 1100G engine, one of Pratt & Whitney's geared turbofan (GTF) engines powering several Airbus and Embraer fleets.

A Modest First Step Toward Automation

While robotic assembly machines are commonplace on factory floors building everything from cars to electronics, Pratt & Whitney's assembly lines remain largely human-dependent. This is partly due to the exacting and unforgiving work of building jet engines, which require a carefully policed logbook of production steps executed to keep the process error-free.

Throughout the factory floor, "Foreign Object Debris" bins remind workers to keep areas clear of any loose materials — from stray threads to gum wrappers. Even small pieces of detritus can become deadly if they end up in a jet intake. Company staff stressed that ensuring a machine could operate error-free in a range of conditions was a time-consuming and critical prerequisite for embracing automation.

BARB — with its upright stance and long yellow arms fitting the mold of a factory robot out of central casting — is the product of a $20 million investment the company has made into automation. It represents a modest first step at integrating automation more fully throughout jet engine assembly, both on the civilian side and in the somewhat more complex military engine business on a parallel production line in the same facility.

Development and Testing

According to Ted Sluis, vice president and manager of Product Delivery Centers at Pratt & Whitney, BARB arrived in Middletown around late 2024 but only came online this spring after extensive testing that ensured the robot's cameras and sensors could reliably identify parts and consistently perform the correct operations.

"There is a visual inspection aspect of it, and when we were doing the initial trials of the parts, we were using scrap parts," Sluis said. "But the scrap parts were old, and we went to make production parts on it, those were new and shiny. The vision system started having issues because it wasn't used to shiny parts; it was used to like the old parts … little things like that, that we had not anticipated. And so a lot of learning meant that it took us all the way through last year, into the beginning of this year to get it to where it could repeatedly get through the entire cycle without a person intervening to do something."

Bearing Assembly Process

According to public production and training manuals, the 1100 engine — assembled in a horizontal position — has seven total bearings requiring assembly. The #2 bearing is a ball bearing that supports the front of the low-pressure (LP) rotor, which extracts energy to power the engine fan and reaches maximum speeds above 10,000 RPM. The #5 and #6 bearings are rear roller bearings.

Sluis said engine assembly involves bearing sub-assembly, including the bearing, housing components, and affiliated seals and covers.

"So it's a handful of parts that you have to get put together into a sub-assembly," he said. "With the types of operations that we're doing, different parts have different clearances. And so to get them to go together, you have to heat one part and cool another part, and you have to orient those in the right way, press them together, let it normalize, inspect it to make sure that it actually meets the right dimensional requirements."

Integrating Automation with Record-Keeping

In the traditional engine assembly process, Sluis said, a mechanic would sign a record at every stage verifying the prescribed action had been completed in the correct order. Integrating the assembly robot into the record-keeping process has been another deliberate effort.

"If a person is doing that work, they would be signing with their badge all the different sequences to say 'I completed this work,'" Sluis said. "In this case, the mechanic is basically signing, saying, 'I provided the parts to the machine, the machine is tracking, I did this, I did this, I did this,' and that's going to be part of the engine build record. The mechanic signs, saying, 'I received the assembly from the automation machine, and I'm going back to the normal process.'"

Efficiency Gains

While the approach to integrating automation into an exacting assembly process has been small-scale to start, Sluis said the benefits in efficiency have been immediately clear, with an 80% reduction in "touch time."