An overview of additive manufacturing or 3D printing.

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Additive Manufacturing
(Session I)
Oct, 2022
By
Vinu B Krishnan, PhD
Design, Materials and Technical Consultant / Mentor

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Overview of Session I
 Additive Manufacturing - Overview
 Industries, Parts & Process
 Types with demonstration videos
 Powder Metallurgy
 HIP (Hot Isostatic Pressing)
 Design for Additive Manufacturing
 Generative Design

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Additive Manufacturing (AM)
 Additive rather than traditional “subtractive”
manufacturing
 3D model is sliced into many 2D layers
 Each layer deposited and fused onto previous
layer to build up a part
 Materials include polymers, ceramics, and
metals
 Traditionally impossible geometries
 Economical for small batches and custom
parts

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Additive Manufacturing

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Industries using AM

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Parts Manufactured using AM

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Support Structure

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The Seven Types
 VAT Photopolymerisation – large bath of liquid photopolymer
resin is selectively cured with a UV light
 Material Jetting – drops of liquid polymer are dispensed
individually and cured with a UV light
 Binder Jetting – powdered material is selectively coated in
binding liquid
 Material Extrusion – or FDM (fused deposition modelling), “hot
glue gun” method commonly seen in hobby printers
 Sheet Lamination – layers are cut from sheets and bound
together using ultrasonic welding
 Directed Energy Deposition – 4 or 5 axis arm deposits material
via wire or powder feed (powderfed fusion) with a laser or
electron beam heat source, similar to automated welding
 Powder Bed Fusion – powder layers are selectively sintered or
melted with a laser or electron beam, commonly called PBF,
DMLS, EBM, SLM, LBM and SLS.
Powder bed fusion (PBF), Direct Metal Laser Sintering (DMLS), Electron Beam melting (EBM),
Selective Laser Melting (SLM), Laser Beam Melting (LBM), Selective Laser Sintering (SLS),

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Directed Energy Deposition

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Selective Laser Sintering (SLS)
Direct Metal Laser Sintering (DMLS)
 SLS and DMLS use a
bed of small particles
 High-power laser
traces one layer on the
surface of the powder
bed fusing the particles
 Alloys include
 Cobalt Chrome
 Stainless Steels
 Nickel Alloys
 Titanium Alloys
 Aluminium Alloys
 Copper Alloys

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Powder Metallurgy (PM)
 Powder metallurgy (PM) is a term covering
a wide range of ways in which materials or
components are made from metal powders
 Hot isostatic pressing (HIP)
 Metal Injection Moulding (MIM)
 Press & sintering
 Additive Manufacturing

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Powder Metallurgy (PM)
 HIP process is typically used for the manufacturing of
massive near net shape parts of several hundred
kilograms
 AM process is more suitable for smaller parts of a
few kilos and it offers an improved capacity to
produce complex metal parts thanks to a greater
design freedom
 Metal Injection Moulding (MIM) and press & sintering
technologies also offer the possibility to produce net
shape parts but they are recommended for large
series of small parts

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HIP (Hot Isostatic Pressing)
 Hot isostatic pressing (HIP) combines high
temperature (up to 2200°C) and a gas
pressure (200–500 MPa), which is uniformly
applied to the powder compact in all
directions

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Advantages of Metal AM
 Increased design freedom versus conventional casting and
machining
 Light weight structures, where material used only where it needs
to be, without other constraints
 New functions such as complex internal channels or several
parts built in one
 Net shape process meaning less raw material consumption,
reducing the number of assembly operations such as welding,
brazing.
 No tools needed, unlike other conventional metallurgy
processes which require moulds and metal forming or removal
tools
 Short production cycle time: complex parts can be produced
layer by layer in a few hours in additive machines

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Limitations of Metal AM
 Part size:
 limited to powder bed size, for standard powder bed systems.
 Direct energy deposition can build large or massive parts, but the
processes are very slow and costly
 Production series: recommended for the production of parts in small
series production
 But progresses are made to increase machine productivity and thus the
production of larger series. For small sized parts, series up to 25000
parts/year are already possible.
 Part design: in the case of powder bed technology, removable support
structures are needed when the overhang angle is below 45°.
 Material choice: though many alloys are available, non weldable metals
cannot be processed by additive manufacturing and difficult-to-weld alloys
require specific approaches.
 Material properties: parts made by additive manufacturing tend to show
anisotropy in the Z axis (construction direction).
 Besides, though densities of 99.9% can be reached, there can be some
residual internal porosities.
 Mechanical properties are usually superior to cast parts but in general
inferior to wrought parts.

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Design for Additive Manufacturing
(DfAM)
 At a basic level, DfAM addresses
fundamental manufacturing considerations
and answers questions, such as “will it print?”
 At an intermediate level, you start to
consider ways to improve the functional
performance of the system by taking
advantage of some unique capabilities of AM
 At an advanced level, you focus on
managing the complexities of moving a
product from the proof-of-concept phase to
full-scale production

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Part Consolidation
 AM opens the door to manufacturing more
complex topologies than would be possible
using traditional means
 It is often feasible (and highly cost-effective)
to simplify assemblies by combining multiple
components into one part

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Architected Materials

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Generative Design
 Generative design is a design methodology
that uses computational algorithms to
generate high-performance geometry based
on specific requirements