Quality Assurance for Electron Beam 3D Printing

The work under development at TWI and Brunel University is to provide quantified measurements for QA of electron beam melting (EBM) equipment, and make the 3D printing process more transferable between machines.

Electron beam melting takes place in a powder bed, mounted inside a vacuum chamber. Quality of build depends on electron beam parameters, therefore a novel probing and analysis system is being developed, which will measure focused spot diameters in X & Y, power intensity and powder distribution.

The system consists of an array of probes, a PC, an arbitrary waveform generator and a data acquisition device. A calibration routine allows positioning of the array of probes inside the vacuum chamber, beam alignment and beam width monitoring. The measurements are taken at many positions over the powder bed. Real time processed data is used to improve the beam quality and finally adjustments may be fed to the EBM machine to compensate for deflection errors. In addition, beam characteristics may be recorded and a report generated.

This work describes the probing system implementation and applied methodologies for measurement and quantifying the beam properties with the aim of ensuring a repeatable and transferable additive process.