December 7th, 2021

New technology improves engine component safety

Sensor, software intelligence capture critical ingot quality throughout the melt processes.

Aerospace Manufacturing & Design | Paul E. King and Andrew J. Elliott

arc position
Arc distributions over a user-prescribed period during the processing of an ingot. Differing arc conditions have different impacts on metal quality.
Credit: National Transportation Safety Board; Ampere Scientific

Commercial air travel is safer than it’s ever been. But mechanical failures can, and still do, occur. Flight UA 328, which left Denver, Colorado on Feb. 20, 2021, suffered a catastrophic engine failure four minutes into the flight. Fortunately, the airplane returned to the airport and landed safely. While the Federal Aviation Administration (FAA) is continually improving safety regulations, there’s more to be done to prevent critical engine failures.

Improvements can be made at the beginning of manufacturing during primary metal processing. Materials must be made to withstand the intense stresses and extreme temperatures components experience, such as turbine disks which hold the turbine blades together while spinning at >10,000rpm and at temperatures up to 1,700°C. Fan blades are also susceptible, as proven with flight UA 328. The National Transportation Safety Board (NTSB) determined the cause was fan blade out failure – two fan blades fractured from metal fatigue, often a result of macroscopic and microscopic discontinuities which can occur during primary metal processing.

Today’s manufacturing processes won’t produce the aircraft engine components of tomorrow. Meeting those standards requires a revolution in parts manufacturing where impeccable processes and precision equipment deliver supreme confidence in the material’s ability to achieve maximum performance.

Right engine of UA 328 showing fire damage to the thrust reversers.

Ampere Scientific and Consarc Corp. joined forces to apply sensors and software intelligence to revolutionize parts manufacturing. Their current mission is to detect conditions during the vacuum arc remelting (VAR) process that can lead to defects in critical engine components. They’ll use this technology to predict conditions that lead to defects and prevent them from occurring.

VAR furnaces remelt and refine specialty alloys which are formed into critical aero-engine parts in commercial and military aircraft. Current VAR furnaces rely on electrical signals for process control and ingot quality assessment rather than direct evaluation and real-time visualization of the growing ingot.

Ampere Scientific is determined to change that with its VARmetric arc positioning sensing technology that provides a view into the melting process. VARmetric combines advanced electromagnetic field sensing with Consarc’s VAR furnace measurements to capture, record, and display operating characteristics of the furnace not previously detectable during melting. It uses Consarc’s controls to monitor the furnace current, voltage, vacuum level, load cell, ram position/speed, and electromagnetic stirring. VARmetric then integrates measurements of the magnetic fields at a multitude of locations throughout the VAR to image the arc’s location interior to the VAR.

The result is real-time data showing:

  • Plots of furnace operational characteristics (current, voltage, vacuum, melt rate, ram speed, etc.)
  • Radial arc position overlaid on video images from VAR annulus cameras
  • Arc distribution through time
  • Electrode shape, position as a function of time
  • Alarms for side-arc conditions, extended arc gaps, other anomalous events or electrode movements
var sensors
VAR Sensors
Credit: Ampere Scientific

This data is available to the operator as the ingot is produced and can be used as part of the record of chain-of-custody for any qualified alloy ingot. This information can calculate the probability for solidification defects during operation as part of digital twinning. This gives metal producers, engine original equipment manufacturers (OEMs), and regulatory bodies more confidence that the materials they’re using are produced consistently and can withstand the rigors they are expected to face in extreme environments.VARmetric captures data throughout the melt process and creates a detailed map to assess ingot quality long before any microscopic or macroscopic quality testing is conducted on finished parts. VARmetric can become an early warning system as the technology matures and stores of data grow, enabling operators to respond proactively during the melt to avoid exceeding process limits during production, leading to optimal results consistently on every melt, every time.

With such guidance, solidification defects will be reduced and confidence in ingot quality will rise. Higher quality ingots yield higher quality components helping the next generation of aircraft fly lighter, faster, stronger, and safer.

Source: Aerospace Manufacturing & Design