Lights-out manufacturing with advanced EDM

Aerospace Techniques of Middletown, Connecticut, has been delivering precision machined components for aerospace power generation and other uses since 1965. The company manufactures a range of unusual and complex shapes from various alloys, using state-of-the-art machining technologies.

While aircraft components remain the focus, Aerospace Techniques also produces parts for the industrial turbine, medical, and electronics markets, owing to the company’s reputation for high precision, superior quality control, and innovative engineering teams.

The company’s core competence remains in blades and vanes for the hot section of aircraft engines. As these parts evolved to modern hollow configurations, cooling holes became the norm for all the major engine manufacturers. Due to the high nickel and cobalt content of the alloys used, fast hole electrical discharge machining (EDM) and laser technologies have become the first choices to produce the precision-tolerance holes required.

Round cooling holes range from a diameter of 0.010" to 0.190", creating the challenge of maintaining surface finish and low recast layers in EDM processing. Holes are often combinations of conical, round, and shaped designs, so to maintain reasonable production levels, it was necessary to find EDMs that would hold tolerance and provide a single-point electrode to mill shaped hole geometries – all while producing a round hole through the airfoil wall in a single step.

Fast hole EDM expertise

A team led by Aerospace Techniques General Manager Fady Elias and EDM Manager Bruce Morin reached out to Beaumont Machine and company founder and President Ed Beaumont for application assistance.

“We entered the fast hole EDM arena in the late 1990s and met with engineers from Beaumont, which has been supplying us machines since then. In this case, we were seeking an ideal scenario of prep the program, load the parts, start the machine, and run it unattended for 10 hours. The team at Beaumont has helped us achieve that goal,” Elias says.

Morin adds, “I was a CNC programmer/machinist when I joined the company and really had no knowledge of the EDM world. However, due to the service and training we received from day one with Beaumont, I quickly became more familiar with both the technology and the machines’ abilities. With our Mastercam and Solidworks software plus the Fanuc CNC onboard the machine, we quickly discovered the best solution for the new types of work we were handling for our customers.”

Today, several Beaumont FH series machines – equipped with robotic tool changers and tool carousels with six size guides and 18 electrodes so the diameter changes can be made automatically – machine highly complex blades and airfoils produced at the company. The machines work on a variety of nickel alloys, plus some stainless alloys, producing a wide range of hole patterns.

A typical job might involve a 1.5" x 2.0" x 0.5" piece with 0.060" diameter flat bottom holes with 0.050" to 0.060" depths and 0.060" wide x 0.100" long flat-bottom slots, requiring plunge milling plus secondary electrode handling and manipulation to create the contour shaping. A combination of ram and wire EDMs produces the parts with seamless transition.

On one job, Morin notes cycle time went from 1 hour to 22 minutes, and on one blade project, production increased from 15 pieces/day to 32 pieces/day. Aerospace Techniques also processes workpieces up to 40" diameter, requiring large work-envelope machines. The total investment in new equipment in 2017 reached $2.7 million, according to Elias.

The investments allow most of the company’s operation to occur unattended.

“Following the training and initial runoff on the machines, which Beaumont delivered in a very thorough and step-by-step manner with my team, the operators quickly grasped the operation and moved into a lights-out environment,” Morin explains. “With only a 15-minute reload time on the workpiece carriage, they were up and running in a short time. The results have taken several forms. It frees up our time to do other tasks, such as tool room projects, as we manufacture our own part tooling, do TIG welding, dot peen marking, and specialty cleaning approval protocols, per customer stipulations.”

A variety of procedures are done in-house at the company’s quality control center, including coordinate metrology machine (CMM) inspection, 3D optical comparator inspection, atomic absorption (AA) spectrum analysis, fluorescent penetrant inspection (FPI), computer integrated airflow testing, and metallurgical micro-evaluation.

Finding an optimum solution

“We knew the Beaumont machines were capital intensive, but their combination of service, performance, and out-of-the-box thinking gave us numerous inspirations to guide the development of our work cell layouts and production scenarios,” Elias says. “A particular challenge for us is the substantial amount of low-volume, high-precision work we do, and Beaumont technicians rolled up their sleeves and joined us in devising an optimum solution.”

He further notes a collateral benefit of this development to his company in a market segment such as medical/orthopedic, where the similar challenge of low-volume, often one-off, work must be done with precision, while machining very tough materials.

Other projects on which Beaumont machines have proven successful include an F-35 Joint Strike Fighter exhaust component, resulting in $1 million in savings.

Aerospace Techniques
www.aerospacetechniques.com

Beaumont Machine
www.beaumontmachine.com

Fanuc America
www.fanucamerica.com

Mastercam (CNC Software Inc.)
www.mastercam.com

Solidworks
www.solidworks.com