The document discusses various metal additive manufacturing techniques including powder bed fusion, directed energy deposition, binder jetting, and sheet lamination. Powder bed fusion techniques like selective laser melting use a laser to selectively fuse metal powder layers. Directed energy deposition techniques like laser engineered net shaping use a laser and metal powder or wire feedstock to deposit material. Binder jetting uses inkjet printing of a binder to join metal powder particles. Sheet lamination techniques like ultrasonic additive manufacturing bond metal foils using ultrasonic vibration. The document explores the process parameters, microstructures, and applications of these various metal 3D printing methods.

1. ADVANCEMENTS IN
METAL ADDITIVE
MANUFACTURING
SEBY VARGHESE
S2 M TECH PRODUCTION
ROLL NO.13
1

2. Contents
 Introduction
 Classification of AM methods
 Metal additive manufacturing
 Powder Bed Fusion
 Directed Energy Deposition (DED)
 Binder Jetting (BJ)
 Sheet Lamination (SL)
 References
2

3. Additive Manufacturing(AM)
 “The process of joining materials to make parts or
objects from 3D model data, usually layer upon layer,
as opposed to subtractive manufacturing
methodologies”
3

4. Classification Of AM methods
 Powder Bed Fusion (PBF)
 Directed Energy Deposition (DED)
 Binder Jetting (BJ)
 Sheet Lamination (SL)
 Material Extrusion (ME)
 Material Jetting (MJ)
 Vat Photopolymerization (VP)
4

5. Metal additive manufacturing
5
Fig 1 Metal additive manufacturing processes

6. Powder Bed Fusion (PBF)
 uses a high-energy power source to selectively melt or
sinter a metallic powder bed
 Selective laser melting (SLM)
 Electron beam melting (EBM)
6
Fig.2 Schematic of SLM
Fig.3 Schematic of EBM

7. Process parameters in PBF
 LBM
Power of laser source
 scan speed
hatch distance
laser tracks
thickness of powdered layer
 EBM
Electron beam power,
Current
diameter of focus
 powder pre-heat temperature
layer thickness
7

8. Porosity in PBF parts
 Types of pores in PBF parts
Fig.4 pore due to trapped gas in SLM
processed TI-6Al-4V
Fig.5 pore due to insufficient heating in
SLM processed TI-6Al-4V
8

9. PBF Microstructure
 Factors affecting grain microstructure
 Temperature gradient
 Solidification interface velocity
Scan speed Laser/Electron beam
power
9

10. Laser Scan Strategy in AM
 laser power
 Laser spot size
 scan speed,
 hatch distance
10
Fig.6 Schematic of laser scanning strategies used

11. Effect of Scanning velocity on
Density in SLM
11
Fig.7 Density depending on scanning velocity and laser power with Ds
= 50 µm, ys = 0.15 mm

12. Density variations with laser power and
scanning velocity in SLM
12
Fig.8 Densities by means of cross sections of SLM samples
depending on scanning velocity and laser power

13. Effect of scanline spacing on
Density in SLM
13
Fig.9 . Density depending on scanline spacing, PL= 900 W, Vs = 1700 mm/s,
Ds = 50 μm (left), Cross sections of SLM samples built with different scanline
spacings (right)

14. Hardness variations with scanning
velocity and scanline spacing
14
Fig.10 . Hardness depending on scanning velocity (left),
Hardness depending on scanline spacing (right)

15. Multi-material PBF
• A critical requirement in multiple material SLM is to deposit at
least two discrete powder materials within one layer.
• 316L stainless steel, In718 nickel alloy and Cu10Sn copper
alloy
• combining powder-bed spreading, point-by-point multiple
nozzles ultrasonic dry powder delivery, and point-by-point
single layer powder removal to realize multiple material fusion
within the same layer and across different layers
15

16. Multi-material PBF
16
Fig.11 Multi-material PBF specimen
Fig.10 Schematic of multi-material PBF
equipment

17. Directed Energy Deposition (DED)
 Uses injected metal powder flow or metal wire as feedstocks, along with
an energy source such as laser or electron beam to melt and deposit the
material on top of the substrate
 Two main methods
1. Metal wire as feedstock
2. Laser Engineered Net Shaping (LENS)
17
Fig 12

18. Materials in DED
 Titanium alloys
 Stainless steel
 Tool steels
 Aluminium alloys
 Refractory metals (tantalum,
tungsten, niobium)
 Superalloys (Inconel, Hastelloy)
 Nickel
 Copper
18

19. Process parameters in laser DED
19
Fig.13 Process parameters in laser DED

20. Effect of layer thickness on thickness
error
20

21. Effect of powder mass flow rate
on thickness error
21

22. Influence of powder mass flow
rate on porosity
22

23. Comparison of DED and PBF
Fig.14 Build-time comparisons for laser-based DED and PBF for a small
titanium nozzle. The material is Ti-6Al-4V.
23

24. Rapid Plasma Deposition
 Plasma-arc + wire (off-axis)
 Closed-loop process control
 Shielding box
 Working volume 1000x500x300mm3
 Aerospace/aviation applications
24
Fig.16 Rapid plasma deposition by
Norsk Titanium

25. Closed loop DED
 Closed Loop DMD is a synthesis of multiple
technologies including lasers, sensors, a Computer
Numerical Controlled (CNC) work handling stage,
CAD/CAM software and cladding metallurgy
 integrated feed-back system
 Geometry control
 Temperature control
 Microstructure control
25
Fig 15 Setup for closed loop DED

26. Binder Jetting (BJ)
 Extension of normal 2d printing to 3d
 a binder is selectively deposited onto the powder bed, bonding
these areas together to form a solid part one layer at a time.
 bonding occurs at room temperature
 Metal Binder Jetting systems typically have larger build volumes
than DMSL/SLM systems (up to 800 x 500 x 400 mm)
 Binder Jetting requires no support structures: the surrounding
powder provides to the part all the necessary support
26

27. Binder jetting
Fig.16 Schematic of binder jetting
27

28. Steps in binder jetting
 First, a recoating blade spreads a thin layer of powder over the build platform.
 Then, a carriage with inkjet nozzles (which are similar to the nozzles used in
desktop 2D printers) passes over the bed, selectively depositing droplets of a
binding agent (glue) that bond the powder particles together.

When the layer is complete, the build platform moves downwards and the
blade re-coats the surface. The process then repeats until the whole part is
complete.

After printing, the part is encapsulated in the powder and is left to cure and
gain strength. Then the part is removed from the powder bin and the unbound,
excess powder is cleaned via pressurized air.
28

29. Process parameters in binder
jetting
 Drying time
 Printing saturation
 Powder characteristics
 Layer thickness
 Binder burnout and sintering
 Sintering additives
 Infiltration of nanoparticles into porous BJ printed parts
29

30. Post processing in binder jetting
 The main drawback of metal Binder Jetting parts are their
mechanical properties, which are not suitable for high-
end applications.
 Reason : printed parts basically consist of metal particles
bound together with a polymer adhesive.
1. Infiltration
2. Sintering
30

31. Post processing in binder jetting
 Infiltration: After printing, the part is placed in a furnace, where the
binder is burnt out leaving voids. At this point, the part is
approximately 60% porous. Bronze is then used to infiltrate the
voids via capillary action, resulting in parts with low porosity and
good strength.
 Sintering: After printing is complete, the parts are placed in a high
temperature furnace, where the binder is burnt out and the
remaining metal particles are sintered (bonded) together, resulting in
parts with very low porosity.
31

32. Advancements in binder jetting
 Binder jetting additive manufacturing with a particle-free
metal ink as a binder precursor
 using metal nanoparticles ink as a binder to replace
polymer adhesives
 Metal-Organic-Decomposition (MOD) ink
 MOD ink contains an organometallic compound formed
by introducing ligands (complexing agents) to metal salts
32

33. MOD ink
 MOD ink is particle-free during printing
1. reducing the risk of clogging inkjet printhead,
2. preventing ink sedimentation and increasing ink shelf life
3. reduces surface oxidation in metal nanoparticles during storage
33

34. Sheet Lamination (SL)
 Also known as laminated object manufacturing(LOM)
 Uses metallic sheets as feedstock
 Uses localized energy source to bond a stack of precision cut
metal sheets to form a 3D object
 Most common technique-Ultrasonic additive
manufacturing(UAM)
34

35. Ultrasonic Additive
Manufacturing(UAM)
 Also known as Ultrasonic Consolidation (UC)
 low temperature additive manufacturing or 3D printing technique for
metals.
 works by scrubbing metal foils together with ultrasonic vibrations
under pressure in a continuous fashion
 No melting occurs
 metals are joined in the solid-state via disruption of surface oxide films
between the metals
35

36. Ultrasonic Additive
Manufacturing(UAM)
36
Fig.17 Schematic of ultrasonic additive manufacturing

37. Process Parameters in UAM
 Weld speed
 Sonotrode oscillation amplitude
 Weld pressure
 Anvil temperature
 Sonotrode topology
37

38. Effect of sonotrode topology on
roughness
38
Fig.19 Different sonotrode topologies (a) smooth topology
(Sa=4.97 μm) and (b) rough topology (Sa=18.87 μm)

39. Advancements in UAM
 Dissimilar material bonding
 Object embedment
Fig.20 fibre embedment using UAM
39

40. Dissimilar material bonding
 possible to create functionally graded metal laminates
 These structures avoid the brittle intermetallics that would form with
traditional thermal bonding processes and avoid the melt point
mismatch that renders many metal combinations impossible
 By varying the ratio of one metal to another through thickness
variations in the structures, material properties can be carefully
controlled and engineered throughout the entire part
 Example :to weld titanium to aluminium
 titanium acts as a heat and wear-resistant layer on the outer edges of an
aluminium component, thus prolonging the life of the base aluminium
component
40

41. Dissimilar material bonding
41
Fig.21 UAM manufactured functional graded laminate that is created
through the alternate layering of Cu (darker layer) and Al (lighter layer) foil
materials bonded in the solid state. (a) shows the laminate during UAM
and (b) shows a close-up of the final Cu/Al functionally graded laminate

42. UAM Material Combinations
42
Fig.22 A chart depicting which materials are ultrasonically weldable and
which have directly been used with the UAM process.

43. Object Embedment in UAM
 a significant level of low temperature and high plastic flow
can occur within the material during ultrasonic excitation
acoustoplastic effect
43
Fig.23 Schematic of the UAM process for object
embedment.

44. References
1. Zhang, Y., Wu, L., Guo, X., Kane, S., Deng, Y., Jung, Y.-G., … Zhang, J.
(2017). Additive Manufacturing of Metallic Materials: A Review.
Journal of Materials Engineering and Performance, 1–13.
https://doi.org/10.1007/s11665-017-2747-y
2. Shim, Do-Sik & Baek, Gyeong-Yun & Lee, Eun-Mi. (2016). Effect of
substrate preheating by induction heater on direct energy
deposition of AISI M4 powder. Materials Science and Engineering:
A. 682. 10.1016/j.msea.2016.11.029.
3. Wei, Chao & Li, Lin & Zhang, Xiaoji & Chueh, Yuan-Hui. (2018). 3D
printing of multiple metallic materials via modified selective
laser melting. CIRP Annals. 10.1016/j.cirp.2018.04.096.
44

45. References
4. Robinson, Joseph & Ashton, I & Fox, P & Jones, Eric & Sutcliffe, Chris.
(2018). Determination of the Effect of Scan Strategy on Residual Stress
in Laser Powder Bed Fusion Additive Manufacturing. Additive
Manufacturing. 23. 10.1016/j.addma.2018.07.001.
5. Buchbinder, Damien & Schleifenbaum, H & Heidrich, Sebastian & Meiners,
Wilhelm & Bültmann, Jan. (2011). High power Selective Laser Melting
(HP SLM) of aluminum parts. Physics Procedia. 12. 271-278.
10.1016/j.phpro.2011.03.035.
6. Janaki Ram, G. D., Yang, Y., & Stucker, B. E. (2006). Effect of process
parameters on bond formation during ultrasonic consolidation of
aluminum alloy 3003. Journal of Manufacturing Systems, 25(3), 221–
238.doi:10.1016/s0278-6125(07)80011-2
45

46. References
7. Friel, R. J. (2015). Power ultrasonics for additive manufacturing and
consolidating of materials. Power Ultrasonics, 313–
335.doi:10.1016/b978-1-78242-028-6.00013-2
8. Fayazfar, H., Salarian, M., Rogalsky, A., Sarker, D., Russo, P., Paserin, V., &
Toyserkani, E. (2018). A critical review of powder-based additive
manufacturing of ferrous alloys: Process parameters, microstructure
and mechanical properties. Materials & Design, 144, 98–
128.doi:10.1016/j.matdes.2018.02.018
9. Shamsaei, N., Yadollahi, A., Bian, L., & Thompson, S. M. (2015). An
overview of Direct Laser Deposition for additive manufacturing; Part
II: Mechanical behavior, process parameter optimization and control.
Additive Manufacturing, 8, 12–35.doi:10.1016/j.addma.2015.07.002
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47. References
10. Choi, J., & Chang, Y. (2005). Characteristics of laser aided direct
metal/material deposition process for tool steel. International
Journal of Machine Tools and Manufacture, 45(4-5), 597–
607.doi:10.1016/j.ijmachtools.2004.08.014
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48. THANK YOU
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