1. High-speed imaging of the powder bed and shield gas
during laser PBF
P. Bidare, I. Bitharas and A.J. Moore
Heriot-Watt University, Edinburgh
R.M. Ward and M.M. Attallah
University of Birmingham

2. Results available online
Open-architecture PBF system
Bidare, R.R.J Maier, R.J. Beck, J. D. Shephard and A. J. Moore,
“An open-architecture metal powder bed fusion system for in-situ process measurements”,
Additive Manufacturing –185 (2017)
High-speed imaging and FE model
P. Bidare, I. Bitharas, R. Jennings, M. Ward, M.M. Attallah, and A.J. Moore, “Fluid and particle dynamics in laser powder bed fusion”,
Acta Materialia (2018)

3. Results available online
Sub-atmospheric pressure measurements
P. Bidare, I. Bitharas, R.M. Ward, M.M. Attallah and A.J. Moore,
“Laser powder bed fusion at sub-atmospheric pressures”,
International Journal of Machine Tools and Manufacture 130–131 65–72 (2018) 

4. Overview Open-architecture PBF system
High-speed imaging and Schlieren imaging
Single track scans
Multiple layer builds
Vacuum 
FE model of laser plasma and shield gas flow

5. Open-architecture PBF system
Lead screw
bearing
Stepper motor and
Lead screw
(x-axis)
Shielding gas chamber
Powder reservoir
Surface plate
Spreader block
Build plate (Coupon)
Linear actuator
(z-axis)
Cross-sectional view

6. Open-architecture PBF system
SPI 400W fibre laser
1064 nm
Laser scanner
Powder reservoir & Spreader block
Support assembly for
Build plate (coupon)
Stepper motor & Lead screw (x-axis)
Surface
plate
Linear actuator (z-axis)

7. Open-architecture PBF system
SPI 400W fibre laser
1064 nm
Designed for single track x-ray measurements
Builds fully dense parts

8. PBF system for High-speed imaging
Camera
‘top’ view
Shielding gas chamber
Powder reservoir
Camera
‘side’ view
Spreader block
Flow straightener
Schlieren illumination
Build plate (Coupon)

9. High-speed imaging: Side view (~10° to horizontal)
Tungsten lamp
Photron FASTCAM Mini
Powder : SS316L Mean diameter 30 µm Camera: 8,000 fps

10. Vacuum chamber for PBF system
Laser
Illumination
Vacuum
chamber
Pressure gauge port
Powder reservoir
Spreader block
Build plate
(Coupon)
Vacuum port

11. Vacuum chamber for PBF system
Phantom V2512
Powder : SS316L Mean diameter 30 µm Camera: 40,000 fps
LED
illumination

12. Summary Open-architecture PBF system
Builds fully dense parts
Imaging of powder bed and shield gas
First layer vs ‘steady-state’ build condition
Sub-atmospheric pressure
~100 mbar and < 10 mbar; Pre-sintering 
FE modelling
Importance of laser plume in shield gas flow