171130 MSc Project (Fabian Plura)

1. SINTAS MEETING 30-11-2017
MSC THESIS: MOISTURE PICKUP & PRINTING IN ADVERSE CONDITIONS
F.PLURA

2. 12/6/2017SINTAS Meeting 2
KEY QUESTIONS
• Which external conditions are influencing the 3D printing process?
• Is there a significant influencing factor? Or is it a combination of
different components?

3. 12/6/2017SINTAS Meeting 3
GLOBAL PROCESS CHAIN 3D PRINTING
POWDER BED FUSION (PBF)
Production of powders
(virgin)
Printing process
(mix of buffer/virgin
powder)
Final parts
Storage
(buffer or virgin)
Reuse of remaining powder
Storage/ transportation: Humidity content? O2/ N2 concentration?

4. 12/6/2017SINTAS Meeting 4
GLOBAL QUESTIONS
Morphology/PSD
Environment/Storage
Process
(PBF)
Which factors has more influence on process?

5. 12/6/2017SINTAS Meeting 5
FUNDAMENTAL COLUMNS OF THE THESIS
Powder Storage Process
- Production - Environment/particles
(oxidation)
- Spread-ability test
(tool NLR)
- Morphology - Moisture film layer - Flowability (visual)
- PSD - Conditioning of
powder
- Apparent density
- Internal Porosity - Determination
moisture content
=> Statistical Image
analysis
=> Theoretical model
particle/environment

6.  Drying: Ramp-up to 150 Celsius by 10 Celsius/min, holding temperature
for 15 more minutes.
 Moisturizing: 25 Celsius/ 80% relative Humidity (RH) for 1,2,3 weeks
=> Spread ability tests with NLR spreading tools
Prior expectations: - Incr. spread ability with decreasing moisture content
- Incr. weeks in climate chamber -> approaching as-rec
state or even going further
12/6/2017SINTAS Meeting 6
CONDITIONING OF POWDER
AS-REC/ DRY/ MOISTURIZED OF BUFFER/VIRGIN POWDERS

7. 12/6/2017SINTAS Meeting 7
SPREAD ABILITY ALSI10MG
Main conclusions (for all materials): - Prior expectations not met (except buffer powder) , no
significant trend visible
=> Understanding necessary: What happened? Why are both spreading tools
performing different?

8. RELIABILITY TEST
MONITORING TEMPERATURE & RELATIVE HUMIDITY
12/6/2017SINTAS Meeting 8
Open container = Exposed to lab
environment
Desiccator = equipped with blue silica gel
Old tool
New tool

9. 12/6/2017SINTAS Meeting 9
CONCLUSIONS OF THE RELIABILITY STUDY
Sample Lost moist. (as-rec)
[%]*
Lost moist. (2nd) dry [%]
Outside 0.08219 0.13879
Inside 0.07413 0.10399
- Difference old tool (upper lines) /new tool (lower lines):
Different way of applying powder (Old tool: funnel-like) =>
better packing of powder layer
- Remaining questions:
- 1) Why is the apparent density decreasing
continuously?
- 2) Why are both samples (stored at significantly different
RH’s) in same range of apparent density?
- 3) In case of 2nd drying: Why is the 1st drying value for
apparent density not reached?
2) Initial moist. content about the same, but quite different at 2nd drying
=> expectation: apparent density @ 2nd drying should be more different when comparing
(outside/inside) sample
(*) same starting condition

10. 12/6/2017SINTAS Meeting 10
UPCOMING
- Statistical image recognition: Trying to obtain PSD for elliptical shaped particles and
compare those results with the Laser Diffraction method
- Theoretical model: Particle/Particle interaction with external factors => fitting measurement
data into that model