ADDITIVE MANUFACTURING - THE PATH TOWARD INDIVIDUAL PRODUCTION - www.technologieland-hessen.de - Technologieland Hessen
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ADDITIVE
MANUFACTURING
THE PATH TOWARD
INDIVIDUAL
PRODUCTION
www.technologieland-hessen.de
CONTENT 2
Foreword . ................................. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction: Additive Manufacturing – potentials within the context of the 4th
industrial revolution – the vision .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2. Additive Technologies and Manufacturing Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.1 Fundamental Principles and Procedures .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2 Data Generation and the Additive Manufacturing Process Chain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
2.3 Process Chains integrating Additive Manufacturing Processes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
3. The Creation of Added Value with Additive Manufacturing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
3.1 Market Assessment .. ............... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
3.2 Qualitative Economic Feasibility Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
3.3 Application Scenarios and Industries .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
3.4 3D Print Service Providers and Content Platforms .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
3.5 Legal Issues in the context of Additive Manufacturing .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
4. Additive Fertigung:
Additive Manufacturing: Selected success stories, potentials and projects from Hessen . . . . . . . . . . . . 62
4.1 Mittelhessen University of Applied Sciences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
4.2 Kegelmann Technik GmbH .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
4.3 EDAG Engineering GmbH .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
4.4 Heraeus Additive Manufacturing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
4.5 FKM Sintertechnik GmbH ..... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
4.6 sauer product GmbH ............. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
4.7 IETEC Orthopädische Einlagen GmbH Produktions KG .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
4.8 Philipps University of Marburg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
4.9 Technische Universität Darmstadt .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
4.10 Fraunhofer LBF . ....................... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
4.11 Hochschule für Gestaltung Offenbach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
4.12 FRAME ONE ............................. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
4.13 University of Kassel ................. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
4.14 Tatcraft GmbH . ........................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
4.15 Fraunhofer IGD . ....................... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
4.16 Fiberthree GmbH . ................... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
4.17 Continental Engineering Services GmbH .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
5. Overview
5.1 Hessian Companies and Research Institutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
5.2 Literature ................................... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
Legal Notice ............................. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
3
FOREWORD
W e a re e xp e c t i ng num e r o us
n e w b u s i ne s s i de as r e l at i ng
to a d d i ti ve m a nuf ac t ur i ng . I n t he
hi g h - te c h s ta te o f H e s s e n, yo u w i l l
fin d a ti g h t c om p e t e nc e ne t w o r k. “
Tarek Al-Wazir
Hessian Minister of Economics, Energy,
Transport and Housing
4
With additive manufacturing processes, single-unit pro- Since the arrival of the first additive manufacturing tech-
duction can be achieved at prices which can already nologies in the mid-90s, several pioneers of innovation
compete with classic mass production: the hearing aid in Hessen have made a name for themselves. For years,
adjusted to an individual ear canal, replacement parts for one of the world’s leading fairs in this area has been held
vintage cars – these are a few examples of where additive in the trade-fair city of Frankfurt. Large Hessen material
manufacturing has already established itself. It is particu- manufacturers are currently entering the market.
larly suitable for products with complex geometry. Its
big advantage is the efficiency of resources. Unlike with We hope that this brochure gives you some food for
material cutting, material is not removed until only the thought for innovative plans and new business ideas. And
desired shape remains. With 3D printing, the material is we would be delighted if you should allow us to support
only applied where it is required. This means that there you in implementing your ideas.
is no excess.
Yours,
This technology is developing at great speed and still
shows a great deal of promise. It isn’t just system manu-
facturers who are benefiting from the high sales figures,
but also material producers and service providers. Big
opportunities are presenting themselves to new players. Tarek Al-Wazir
Hessian Minister of Economics, Energy,
Transport and Housing
5
1. INTRODUCTION:
DDITIVE MANUFACTURING – POTENTIALS
A
WITHIN THE CONTEXT OF THE 4TH
INDUSTRIAL REVOLUTION – THE VISION
The development of additive manufacturing procedures manufacture – which can be customised well into the
(AM for short) in the 1980s made important contributions production process. The digital factories will no longer
to the groundwork for the next, the fourth, industrial rev- only be located in the Far East; instead, they will consist
olution. While the first industrial revolution in the second of regional decentralised production units which make
half of the 18th century refers to the transfer of manual it possible to offer ‘individual items from the assembly
activities into mechanised processes using water and line’ at prices comparable with mass-produced items.
steam power, the second industrial revolution made it
possible to mass-produce with divided responsibilities Products, machinery and transport boxes are linked with
at electrically operated assembly lines. The third big the web via microchips. The Internet of Things will allow
development leap for industrial processes was the use the self-organisation of intelligent production procedures
of information technologies to automate production. The and increase productivity by up to 50 percent. In addition,
intelligent organisation of decentralised production units the storage of raw material information in the product
by linking information and production technology via the will promote recyclability and enable closed material
Internet of Things will offer the foundation for the fourth cycles. Here, experts estimate a medium-term energy and
industrial revolution where experts see great potential resource savings potential of around 20 to 25 percent.
for the German economy among the global competition.
The additive manufacturing process is expected to play a
It is expected that in the future, customers will be able crucial role in the context of the fourth industrial revolution.
to purchase a product via internet portals which can The generative nature of these technologies complete-
access, modify and archive data for components as well ly revises the previous understanding of conventional
as monitor the status of a production order. The manu- material-cutting techniques such as milling, drilling or
facturing process with decentralised production units turning. Here, it is not just a case of saving resources
will be carried out in an effective location according to and avoiding production waste; it is possible to produce
the spatial location of the customer and the equipment product parts with the kind of complex geometries which
available at the production units. The products themselves would not be possible at all if conventional methods such
will not be sent around the globe, just the data for their as casting were used.
6
Experts assume that generative manufacturing will first But the Western world is not alone in striving for a greater
establish itself as an addition to the existing production use of additive manufacturing processes: Asian countries
processes. Already today though, the large number of are also positioning themselves with the provision of
small-scale company foundations brought about by the financial backing. In China and Singapore, three-figure
further development of additive manufacturing processes million amounts have been set aside to prepare the local
is striking. Operating mini factories with new business industry for the transformation process into the age of
models and unique products has been made possible the Internet of Things. China is already conjecturing a
by 3D printing entrepreneurs in almost all larger cities. turnover of 1.12 billion US dollars gained in 2016 in the
These entrepreneurs were also able to find the necessary 3D printer and additive manufacturing market. The China
capital on the internet and social media using Crowd- Industry Information Institute has forecast an amount of
funding campaigns (Cf. Horsch, Florian: 3D-Druck für 7.68 billion US dollars for the Chinese AM market in the
alle – Der Do-it-yourself-Guide. [3D Printing for Everyone year 2020, which would correspond to around a third of
– The Do-It-Yourself Guide] Munich, Vienna: Carl Hanser the global overall market.
Verlag, 2014).
The generative manufacturing market is still manageable.
“There will be plenty of niches”, says internet visionary It is seen as fact for a few application areas and industry
Chris Anderson as he looks to the future of 3D printing. sectors that there will be a transformation process to involve
“We will just be seeing more of everything: more innova- a stronger use of additive manufacturing technologies.
tion in more locations from more people concentrating The speed of the transformation process is influenced
on smaller niches. As a whole, all these new products by numerous factors. Above all, the often necessary ex-
will reinvent the industrial economy, often with just a pense of post-treating components produced in additive
few thousand pieces each time, but these will be exactly manufacturing processes makes even more development
the right products for the increasingly demanding con- efforts necessary. But more and more system manufac-
sumer.” (Source: Anderson, C.: Makers. Das Internet der turers are designing the processes and their material
Dinge: die nächste industrielle Revolution. [The Internet logistics for mass production. The products and areas
of Things: The Next Industrial Revolution] Munich, Vienna: of application most suited for additive manufacture are
Carl Hanser Verlag, 2013) currently the subject of intensive discussions. Whether we
will in retrospect attribute the character of an industrial
This development also appears attractive to countries revolution to the change remains to be seen. The market
which have permitted an enormous reduction of industrial developments over the last five years, however, allow us
production to make room for the service sector over the to suspect a large potential, above all for German and
last few decades. Additive manufacturing technologies Hessian companies. For this reason, the following chapters
are recognised and perceived as the key for the re-in- will describe in more detail the essential technological
dustrialisation of national economies. boundary conditions of additive manufacturing processes
and their potential for the various industrial sectors.
In his State of the Nation speech in February 2013, former
US president Barack Obama described additive manufac-
turing as the foundation for a new growth in US production.
In total, the White House set aside a billion US dollars
to promote the American economy and established a
network of support institutions for this. With the research
programme Horizon 2020, the European Commission
wishes to support the expansion of additive manufactur-
ing in Europe and strengthen it with innovations in this
area. While primarily American companies dominate the
areas of extrusion processes and filament printing, the
metal systems necessary for industrial production in the
automotive and aerospace sectors are mainly dominat-
ed by German system manufacturers such as EOS, SLM
Solutions and Trumpf. The takeover of Swedish system
manufacturer Arcam and the German technology platform
Laser Concept by American engine manufacturer GE
Aviation in 2016 shows what a high importance additive
manufacturing has gained for the USA.
7
2. ADDITIVE TECHNOLOGIES AND
MANUFACTURING PROCESSES
In the science-fiction saga Star Trek, the ‘replicator’ is is formed by so-called additive manufacturing principles
a system which can make components and weapons, which, unlike conventional production processes, do not
food and drink out of individual atoms, in a seemingly remove material (as with turning, drilling, sawing, milling)
arbitrary manner. Marshall Burns named his idea of the or reshape materials (as with bending, drawing); rather,
digital home factory in 1987 ‘Fabber’ – a small decentral- this approach generates the structures respectively. Thus,
ised manufacturing unit which was meant to make the the term additive (sometimes generative) manufacturing
vision of the production of individual parts into reality. has established itself in the specialist literature. Due to
Since then, over 20 years have gone by and the further the highly increasing use and commercialisation into the
development of production technology, software and consumer area, the name ‘3D printing’ has now become
materials have made the future scenario ever more real- the blanket term for the various process principles.
istic (Peters 2011). The foundation for the development
8
2.1 FUNDAMENTAL PRINCIPLES AND PROCEDURES
The additive manufacturing processes and system types A selection of the individual technologies is generally
common today can be subdivided into five additive manu- based on the materials which can be used, the precision
facturing principles according to the materials used. Here, which can be achieved, the potential mechanical quality,
we assume different semi-finished products with various the maximum system construction space, along with the
starting materials and operating principles which effect cost framework. Given the current market dynamics, the
the layered structure of the components. In this way, the conditions are in a constant state of flux.
variety of systems used today can be subdivided into
the process groups stereolithography, laser sintering/
laser melting, binder jet printing, fused layer modelling
or layer laminate manufacturing.
Classification of additive manufacturing procedures
Solid Liquid
Wire Powder Film / sheet Liquid bath
PHYSICAL BASIC PRINCIPLE / TECHNOLOGY
Melting and Melting and Bonding Cutting and Photo-
hardening hardening via binder joining polymerisation
Material extrusion Powder-bed-based Binder jet printing Sheet / film Material
bonding lamination printing
AM PROCEDURE
Fused layer Laser Laser beam Binder jet Layer Stereo-
modelling sintering melting printing laminating lithography
Plastic Plastic, Metal Gypsum, sand, Paper, Resin /
metal alloy ceramic alloy starch, plastic, PVC film, thermosetting
metal wood plastic
Division according to Dr. Ing. R. Anderl (Qualified Doctor of Engineering), Technische Universität Darmstadt, September 2017
9
1 Wiper distributes polymer
2 Laser passes over the surface
3 Construction platform lowers
4 Polymer hardened by laser
Mirror
Laser
2 Wiper 1
2.1.1 Stereolithography (SL)
4 Workpiece
Construction platform
Stereolithography (SL) was developed at the University 3 Resin container
of Texas in Austin at the beginning of the 1980s and is
(Liquid polymer)
regarded as the oldest additive manufacturing process.
At the end of 1987, 3D-Systems Inc. presented the first
system and has marketed it ever since. Stereolithography
was registered by Chuck Hall for patent as early as 1984.
Stereolithography currently achieves the greatest possible The stereolithography process
precision. As a result, it is the most important technique
for creating master forms for fine casting, polyamide and
vacuum casting. FormLabs launched the first SL desktop
system on the market in 2012. Materials
Stereolithography systems can only process liquid pho-
topolymers such as epoxy resin or acrylic resin (vinyl-based
The process polymers even less so). After hardening, these materials
possess sufficient stability and temperature resistance
Stereolithography creates component geometries based between 50-60 degrees Celsius. In the meantime, the
on 3D CAD data by means of locally hardening (curing) different resin systems are available on the market with
a light-sensitive photopolymer with the help of a laser transparent, opaque, flexible, bendable, thermal stability
beam. Photopolymer resin is first filled into a resin bath and biocompatible properties.
and the component platform is submerged below the
surface to a depth equal to the thickness of one layer A large disadvantage of the process technology is that
(usually between 50 and 100 microns). Exposing the the classic approach, including resin bath, does not allow
lines or layers of the shaped part geometry to the laser different materials to be used during a single working
hardens the photopolymer. This creates the first layer process. Resin systems in liquid form also have a significant
of the desired component. The component platform is environmental impact and, moreover, have a limited shelf
progressively lowered in steps equal to the thickness of life. The further development of the resin mainly focuses
one layer. The resin flows onto the platform from the side on improving thermal stability.
and a blade distributes the resin equally across the already
hardened structure before the next layer is exposed to
the laser. The process is repeated until the shaped part
has been completed and the desired component height Component sizes, precision, reworking
has been reached. For a few new systems, the compo-
nent does not move downwards with the construction Stereolithography can achieve the highest precision
platform during the process, but moves slowly upwards among additive manufacturing processes. This is primarily
out of the resin bath. due to the thin layers with a detailed resolution of 0.01
to 0.02 millimetres. Today’s components have very good
Thin supporting structures are required to prevent the surface qualities, they are smooth and the layer structure
subsidence of the overhanging layers in the resin bath is imperceptible. Standard systems have a construction
and to stabilise the geometry. These have to be detached space with dimensions between 250 x 250 x 250 millimetres
from the component platform after removing the com- (LxWxH) and 1000 x 800 x 500 millimetres. When it comes
ponent. The stereolithography components must then to a construction space of 2100 x 700 x 800 millimetres,
be stored under UV light in order to completely harden the manufacturers refer to a mammoth stereolithography
the material. As an alternative to the laser, some systems system. Larger components can be assembled from
utilise UV lamps and a screen. The screen only allows the multiple smaller components. Subsequent surface treat-
UV light to penetrate at the points where the resin should ment using varnishing, coating or metallising is common.
be cured. This eliminates the complex mirror unit required However, the semi-transparency of the material is lost as
to control the laser beam. a result. The surface quality can be further enhanced by
polishing or material cutting.
10Samsonite S’cure prototype in the Mammoth stereolithography system (Source: Materialise)
Application Special processes and system types
Stereolithography is highly important for model construc- PolyJet Modelling (PJM))
tion as a means of manufacturing demonstration objects.
Thanks to their very high quality, the components are Polyjet technology (also known as Multi Jet Modelling
also suitable for use as functional prototypes or master MJM) can be compared to inkjet printing. A printhead
models for fine casting and vacuum casting. However, applies layers of liquid photopolymer to the component
stereolithography components generally cannot be used platform. These layers are then immediately hardened
directly due to their low thermal stability. Process variants using UV light. In this case, the resin bath is not required.
can now also be utilised to generate nanostructures However, supporting structures also need to be printed
and microstructures. Biocompatible resin systems are to generate protruding elements. Polyjet modelling
being used more and more in dentistry and biomedical achieves very high levels of precision of 16 microns for
technology. the Z axis and 42 microns for X and Y axes. Furthermore,
it is the only system technology capable of utilising three
different materials in one process to create multi-material
applications (for example, hard-soft compounds).
Cost-effectiveness
By virtue of its history, stereolithography is the most Digital Light Processing (DLP)
frequently used additive manufacturing technology. The
prices for common stereolithography systems have fallen Digital light processing is another variant of the stereoli-
in recent years. Nevertheless, they still exceed 50,000 eu- thography process and works with UV light to harden the
ros. As a result, a number of service providers have been photopolymer layer by layer. The light first hits the surface
established. Since 2012, desktop systems and kits with of a microchip into which numerous movable micro-mirrors
lower precision have been available from 4,000 euros. are integrated. The beams of light are then reflected onto
However, the material is four times as expensive as the the areas of the construction space to be hardened, and
material used in extrusion systems such as FLM (fused serve to successively generate the component structure.
layer modelling; see chapter 2.1.3). Furthermore, as the DLP systems are very compact, comparatively affordable
excess material remains in the construction space after the and are the preferred system in jewellery manufacture or
manufacturing process, a material consumption higher biomedical technology, for example.
than the actual component volume has to be included
in the cost calculations.
Micro-Stereolithography (MSL)
Weighing only 1.5 kilograms and with the dimensions
of a milk carton, the world’s smallest stereolithography
printer was developed by Professor Jürgen Stampfl and
his team at the Technical University of Vienna in 2013.
It works with liquid resin, which is selectively hardened
through the use of LED light. The layers have a thickness
of 0.05 millimetres. The technology is regarded as having
major potential for future applications, which is why other
research institutions are also working on micro-stereoli-
thography.
11The exposure process when 3D printing high-performance
ceramics in the LCM process (Source: Lithoz)
Continuous Liquid Interface Production (CLIP)
In the spring of 2015, a new additive printing technology
Lithography-based Ceramic Manufacturing (LCM) was introduced in the USA based on photopolymerisation,
which is supposed to be 25 to 100 times faster than the
The LCM process for additive manufacturing of high-perfor- conventional process and leaves behind no visible layer
mance ceramics was developed at the Technical University structures. The additive process takes place in a resin vat,
of Vienna between 2006 and 2010 and has been mar- the base of which consists of a light- and oxygen-perme-
keted by Lithoz GmbH since 2011 as a spin-off company. able membrane. An ultraviolet beam of light illuminates
It is based on exposing a photo-sensitive resin contain- the desired cross-section of the object from underneath
ing ceramic particles. The layers of resin are hardened through the base of the bath onto a platform which is
progressively to form a plastic-ceramic blank with the slowly but continually pulled upwards out of the resin
photopolymer as a bonding agent between the ceramic bath. The introduction of oxygen prevents hardening of
particles. The bonding material is then removed through the entire surface of the construction space. A specially
pyrolysis and the ceramic particles are thermally sintered developed software controls the whole process.
and permanently melted together. During de-bonding, a
degree of shrinkage must be taken into account. Subse-
quently, the components have a density of 99.4 percent.
Silicon printing
In 2016, chemistry company Wacker first introduced a
technology for the layered construction of components
from silicon elastomers. This had not been possible
before due to the high viscosity of the material. With
the so-called Drop-on-Demand-Jetting, the material is
applied to a construction platform from a printhead drop
by drop and then cured under UV light. Layer by layer,
homogeneous part geometries with smooth surfaces
arise which have technical qualities comparable to those
of standard injection-moulded silicon parts. This process
achieves 85-90 percent of the stability generated by the
conventional process. Hollow spaces and overlays can
be achieved with water-soluble supporting materials.
Futurecraft 4D – a sole for a sports shoe manufactured
additively in the CLIP process (Source: Adidas)
Gel Dispensing Printing (GDP)
GDP is a gel-based process which was developed by
an Israeli systems builder to create particularly large
plastic components. Using an extruder, a highly viscous
acrylate-based gel is applied in layers and hardened by
way of UV light. The light source is located directly on the
printhead. The system has a construction space of 1.17
x 1.5 x 1.8 metres and achieves a construction speed of
0.33 metres per hour along the Z axis with a throughput
of up to 2 kilograms per hour.
12 ACEO 3D-Silikondruck (Quelle: Wacker)2.1.2 Selective Laser Sintering
Thanks to its ability to achieve qualities similar to the ones
of series material, selective laser sintering (SLS) is one of
the most important powder-bed processes for industrial
applications. It was developed in the mid-1980s at the
University of Texas by Joe Beaman and Carl Deckard.
Laser sintering works with powdered starting materials
which are melted using a laser. It has long been used for
The laser sintering process (Source: EOS)
mainly prototype and tool construction. In the present
day, it is also one of the most important additive manu-
facturing processes for direct component manufacture
(Direct Digital Manufacturing). At the beginning of 2014, The process
a number of key patents for selective laser sintering ex-
pired. This means that we can expect a decrease in the Selective laser sintering is based on the local sintering and
consistently high prices for components and systems melting of powdered materials through the heat generated
over the next few years. by a laser beam, utilising 3D CAD data. A roller-shaped
coating unit applies a thin, even layer of powder to the
The term selective laser melting (SLM) is now utilised when printing bed and smooths it. Exposing layers or lines of
referring to processing metal powders. As a result of the the corresponding areas results in the melting of the
use of multiple lasers in one system, a productivity increase powdered material, which by subsequently cooling and
of 100-fold up to 1,000-fold is expected in the coming hardening creates a shaped partlayer. Once the exposure
years. With the powder-based Multi-Jet Fusion large-scale of a component layer has been completed, the printing
system, PC printer manufacturer Hewlett Packard entered bed moves one layer downwards and material powder
the 3D product printing market in 2016. GE Additive also is applied again (material thickness between 0.001 and
introduced an SLM large-scale system under the name 0.2 millimetres) and the sintering process is repeated for
of A.T.L.A.S. at formnext 2017, the international additive the next layer structure. Because the solidified material
manufacturing trade fair. In 2016, the first desktop SLS composite is surrounded by loose powder, a supporting
systems appeared on the market for a purchase price of structure is not required to construct protruding elements.
5,000 to 10,000 euro. However, additional structures are required to hold the
component in position when working with high-energy
lasers. The entire printing area in most systems is heated
to a temperature below the melting point of the powdered
material used to reduce the process time. The entire
printing area has to be cooled evenly over a period of
several hours before removing the finished component
from the powder bed. Unused powder can be reused.
Mirror
Laser
2
Roller
1
4 Workpiece 1 Roller distributes polymer
Construction 2 Laser passes over the surface
platform
3 3 Construction platform lowers
Powder
4 Powder hardened by laser
Powder store or powder collecting vessel
The selective laser sintering process
13Materials
In principle, any material which can be melted and man-
ufactured as a powder is suitable for use with selective
laser sintering. Numerous plastics (for example PA 22, PA
12, PS, PEEK, thermoplastic elastomers), ceramics, metal
alloys (tool steel and stainless steel, aluminium, titanium,
cobalt-chrome, bronze, precious metals, nickel-based
alloys) and quartz sand are commercially available. The
powders are generally manufactured synthetically be-
cause of the need for an even grain size. When handling
powdered materials with grain sizes between 20 and 100
microns, the existing legal regulations regarding work
safety apply. Furthermore, experts such as representa-
tives from the Federal Institute for Occupational Safety
and Health (BAuA) strictly advise caution when handling
the powder as the ultrafine particles can enter the human
Removing the component from the powder bed
lung. As such, wearing a mask is recommended. When (Source: Evonik Industries)
processing metallic powder, a protective gas such as ni-
trogen or argon is normally used inside the compartment
to prevent oxidation.
Component size, precision, reworking
Researchers at the Fraunhofer Institute for Laser Technolo-
gy (ILT) in Aachen have succeeded in additively manufac- The construction spaces of laser sintering systems are
turing components consisting of different copper alloys currently between 150 x 200 x 150 millimetres and 1100 x
with a density of 99.9 percent by integrating a 1,000 watt 1100 x 450 millimetres. Some large systems work with up
laser system into an existing SLM system. The process also to four lasers to shorten processing time. The construction
allows objects to be manufactured out of high-strength rate for metal systems is currently between 2 and 100 cubic
zirconium oxide ceramic and aluminium oxide ceramic. centimetres per hour. Systems with up to eight lasers are
The market dynamics mean that the range of printable currently in development. Laser-sintered components
powdered metal alloys is constantly expanding. For exam- have rough surfaces as a result of the grain sizes of the
ple, Heraeus has specialised in the provision of stainless powder. As a rule, the components have a precision of
steel powder for electron beam melting (EBM) and laser +/- 0.1 millimetres, while values of +/- 0.02 millimetres
beam melting (LBM). Platinum group metals (PGM), gold have now been achieved for metal components. The
and silver alloys, refractory metals, amorphous metals, layer thicknesses can vary between 1 and 200 microns.
titanium, titanium aluminides and customer-specific alloys The usual layer thickness for metals such as stainless steel
are offered. Special developments such as inter-metal and tool steel is 20 microns or 40 microns, in the case
alloys, bioresorbable materials, gradient materials and of aluminium, it ranges from30 to 50 microns. Whereas
amorphous metals (metallic glasses) are also available. creating highly dense metal components required infil-
The manufacturer makes the optimal processing param- tration with low-melting metals up until a few years ago,
eters available for each metal powder in the context of laser beam melting (LBM) now generates highly dense
the additive manufacturing process. components (> 99.5 percent) with very good mechani-
cal characteristics. In fact, the material strength actually
exceeds that of commercially produced components in
some cases. Depending on the component geometry,
significant warpage must be factored in as a result of the
thermal influence of the laser, in particular for the LBM of
metal parts. The rough surfaces can then be smoothed
to a glossy finish using ablative processes such as mill-
ing. Before starting a new LBM process, the component
platform must generally be face milled.
14Cost-effectiveness
Because of the high system costs (average price of an
industrial system: 80,000 US dollars; Horsch, Florian:
3D-Druck für alle – Der Do-it-yourself-Guide. Munich,
Vienna: Carl Hanser Verlag, 2014) the use of laser sinter-
ing must be carefully calculated. In a single work stage,
several component geometries are usually manufactured
at the same time and the construction platform is densely
packed to make operating the system financially viable.
The costs for laser-sintered components range from a
few hundred to several thousand euros, depending on
Laser-sintered handles of the Nikon Metrology Scanner with the material used. As a result, the costs are higher than
flocking (Source: Materialise) those of other processes, which still tends to make its use
in a small-company context impracticable. With increas-
ing rates of construction, the costs will sink in the future.
Application Service providers are widely spread.
Up until a few years ago, SLS or SLM components were
primarily utilised as functional prototypes. Today, laser
sintering or laser melting can also be employed to directly Special processes and system types
manufacture customised components and small series. The
typical areas of application include biomedical technology Electron beam melting (EBM)
(such as tooth inlays, implants, hearing aids), tool and
die manufacturing (alloy die casting and fine casting, for In one process variant an electron beam is used instead
example) along with mechanical engineering, aerospace of a laser to achieve a higher power output (3 – 10 kilo-
and the manufacture of replacement parts in vehicle watt in comparison to 250-1,000 watt for SLS/SLM). This
construction. Laser sintering has also been utilised in the allows even high-strength steels to be manufactured with
design and jewellery industry for approximately a decade. a shorter processing duration. Electron beam melting
GE Aviation has set up a site with additive production enables the direct manufacturing of metallic components.
facilities in Alabama where laser sintering systems are For this reason, the Swedish systems manufacturer Arcam
used to manufacture components for aircraft engines. In AB markets its EBM systems under the brand name of
2016, the company took over the two European system ‘CAD-to-Metal’.
manufacturers Arcam and Laser Concept.
SLS extension cable ‘Double Helix CABLE’ (Source: CIRP, Design : Yusuke Goto)
15Multi-material laser beam melting
Until now, laser sintering processes could only process one
material. With a view to expanding additive production,
the generative manufacture of composite structures or
the combination of various material qualities in metallic
high-performance components would be very interesting.
For more than three years, scientists at the Fraunhofer
Desktop SLS system (Source: Sintratec) IGCV have been conducting research on the simultaneous
processing of two metal alloys in a construction process
Desktop SLS using laser beam melting (LBM). In summer 2017, the first
3D printed multi-material component was presented. The
After key patents for selective laser sintering expired, success is the result of a new kind of application method
new system manufacturers appeared in the market. Here, of an LBM system which was integrated on a software and
among other things, the market focus is on small and hardware basis. Here, a 3D multi-material component
affordable desktop solutions. One of the first mini-laser could be produced from tool steel 1.2709 and a cop-
sinter systems was introduced in 2015 and comes from per-chrome-zirconium alloy (CCZ) in an additive manner.
Polish start-up “SinterIT” from Cracow. The system has
dimensions of 66 x 62 x 40 centimetres, weighs only 40
kilograms and has a maximum construction space of 150 x Laser powder coat welding
200 x 150 millimetres. With a laser diode output of 5 watt,
layer thicknesses between 0.075 millimetres and 0.175 Laser coat welding (LMD) is a process which has been
millimetres can be achieved. With the black polyamide established for years for the application of thick metallic
powder (PA12), the companies are offering a material with layers as a wear-resistant coating or to repair a compo-
which rubbery, flexible components can be implemented. nent. It is not a laser sintering process, however, it is used
Further suppliers of affordable SLS systems are Swiss today in the context of metallic 3D product printing. Here,
company Sintratec and Italian manufacturer Sharebot. metal powder is blown into a laser beam. The high energy
output of the laser beam melts the powder and binds it
metallurgically into a permanent layer. On the basis of
HP Multi Jet Fusion 3D-CAD data, 3D metal structures can be created. The
component size is not limited when using the laser powder
The powder bed technology from Hewlett Packard is a coat welding process. The smallest structural resolution
large-scale system (construction space: 406 x 406 x 305 is 30 microns. Steel, titanium, aluminium, nickel and
millimetres) for additive product printing which was pre- cobalt alloys can be processed. Inter-metallic titanium
sented in 2016. It works with an infra-red energy source aluminides and nickel-based high-temperature materials
rather than with a laser. The plastic powder is applied are currently in development.
in layers, using an inkjet printhead, two bonding liquids
with different thermal conductivity are incorporated. One
is particularly thermally conductive and strengthens the
melting effect of the particles in the areas of the desired
component. The other liquid is applied to the edges of the
part geometry and acts as a thermal blocking layer. The
result is sharp edges, smooth surfaces and a clean print
result. Layer thicknesses of 70-80 microns are possible.
The system is first optimised for the use of a fine-grained
PA 12 powder from Evonik. With a print speed of 4,500
cubic centimetres per hour and a possible resolution of
1,200 dpi, the system is a competitor of plastic injection
moulding in small-series production.
161 Supporting and construction material
is drawn into the printhead
2 Extrusion head heats the supporting
and construction material
3 Construction platform lowers
1
4 Construction and
supporting material
is applied
2
2.1.3 Fused Layer Modelling Extrusion nozzles
Extrusion
head
Workpiece
As a result of the expiry of a number of important industrial 4
Supporting material
property rights in 2009, there has been a development
Construction
boost for so-called fused layer modelling processes. platform
Systems following this process approach are now among 3
the most important additive manufacturing techniques
for use in creative professions and private contexts. This
is due to the less complex design of the systems, the easy Roll Roll
handling and the broad range of available materials. The construction
material
supporting
material
good mechanical qualities also play a role. Because the
systems generally work with fusible filament materials, The extrusion process
the terms fused filament fabrication (FFF) and fused layer
modelling (FLM) have become prevalent. The commonly
used term fused deposition modelling (FDM) is a trade-
mark of the American company Stratasys Ltd. Besides the
filament printers, so called fused granular fabrication (FGF) The process
printers using granulate have also been established on
the market. These allow for quick 3D printing of particu- Fused layer modelling processes work with a material
larly large components. Cincinnati Inc. (USA) operates a which softens when heated. Similar to a hot glue gun,
BAAM system (Big Area Additive Manufacturing) with a the material is pressed through a heated nozzle and ap-
construction space of 6 x 2.3 x 1.8 metres. plied either in lines (for example FLM) or in droplets (for
example freeformer). A control mechanism regulates the
distribution of the layers of the material on the component
platform or on the existing structure, where the material
then cools and hardens immediately. The component
is manufactured successively by fusing the individual
layers. The print bed is lowered a fraction of a millimetre
after every layer. The layer thickness is determined by
smoothing with the nozzle. Common layer thicknesses are
between 0.025 and 1 millimetre. Undercuts and hollow
spaces are only possible to a limited degree with this
process. As such, fine supporting structures are required
to manufacture steep component geometries. On new
system types, the supporting material is simultaneously
supplied from a second coil and applied. The supporting
construction has to be removed after printing. The use
of a water-soluble or an alkaline-soluble thermoplastic
is helpful for this.
Materials
Lange Jahre waren die für das Fused Layer Modeling For
many years, the materials which could be utilised for fused
layer modelling were restricted to a few thermoplastic
materials such as ABS, polyester or polycarbonate, or
various types of wax. With the invention of bioplastics, PLA
became the new standard material. Due to the widespread
use of filament printers in creative professions, the market
reacted with new materials and composites to meet the
demand for more versatile design options. Filaments are
now available which are capable of generating wood-like
(such as LAY-Wood), ceramic (such as LAY-Ceramic) or
The extrusion process in operation
(Source: Delta Tower, Thorsten Franck)
17sandstone-like surfaces (such as LAY-Brick) or which have Application
electrically conductive, magnetic or visual properties. Fila-
ment solutions for the implementation of 3D membranes Although additive extrusion systems were primarily used
and porous filters or bendable, rubber-like objects are for manufacturing demonstration models, they are now
also available on the market. The BioFabNet project has seeing more widespread use in direct product manu-
been developing organic-based materials solutions, for facturing and in private applications. More and more
printers in the consumer sector in particular, since the companies are entering the market for systems suitable
end of 2013. Several scientists and designers have also for office use. Applications for the furniture industry and
been focusing on the development of filament solutions interior design are currently being tested as a result of the
based on waste materials and recycled goods. In autumn development of higher quality materials. DIY shops have
2014, American Mark Forged from Boston presented also expanded their range of 3D printers and services to
the world’s first carbon fibre filament printer. In 2017, include options for the creative DIY fan.
several manufacturers of metal filament also joined in to
make it possible to manufacture metal components in an
affordable manner by using filament printers.
Cost-effectiveness
The prices for filament-based printers have decreased
significantly since it has become possible to purchase
construction kits on the internet. They can now be pur-
chased from trade dealers at prices between 500 and
800 euros. Construction kits are available for less than
200 euros. However, the low-cost systems do not deliver
high precision. Higher quality systems in the consumer
sector are available at prices between 1,500 and 3,000
euros and industrial systems at a price no less than 10,000
euros. The filaments are offered for 10 to 50 euros per
kilogram in various colours.
Lay-Wood wooden filament (Source: ccproducts) Special processes and system types
BIG Fused Granular Fabrication (FGF)
Component size, precision, reworking The start-up, BLB Industries from Värnamo in Sweden
presented the first European FGF large-scale printer
The sizes of the systems available on the market range in 2016. This can process standard granulate and ad-
from just a few square centimetres to more than a square ditively produce plastic parts in a construction space
metre. Generally, the process technology is not limited with the dimensions of 1.5 x 1.1 x 1.5 metres and with a
to one construction space as the nozzle with the filament throughput of 6 kilograms per hour. The system is based
could also be moved with a robotic arm. Reworking is a on the platform concept and can be adjusted according
complex process, given that thermoplastics are generally to size. The developers state that the maximum size is 5
used. ABS surfaces, for example, can be vaporised, edged x 5 x 5 metres and the maximum production capacity 35
and smoothed with acetone. Imprecision along the Z kilograms per hour.
axis must be factored in because of the nozzle diameter,
in particular with small components. Due to different
solidification rates within the printed part, warpage has Freeformer
a negative impact on the quality of the component.
Additionally, individual layers may become de-bonded. The die casting systems manufacturer Arburg entered
the additive manufacturing market at the end of 2013
with the freeformer. As such, the mechanical engineering
company was the first manufacturer to use commercially
available material in the form of standard granulate. This
is melted in a heated plastifying cylinder and applied in
the form of plastic droplets. The patented nozzle cap
18utilises high-frequency piezo technology which enables
rapid opening and closing for up to 200 plastic droplets
per second and a precise material application. Using the
series material generates components which have 70 to
80 percent of the strength of comparable die-cast parts.
The freeformer has a construction space of 230 x 135 x
250 millimetres. Components featuring different plastics
(for example hard-soft-compounds) can also be created
with the use of a second nozzle.
High-performance PEEK plastic filament
The start-up Apium Additive Technologies from Karlsruhe
is the first company to make it possible to use filament
printing for high-performance polymers such as PEEK
(polyether ether ketone) for industrial applications with Fibre-reinforced 3D printing (Source: Mark Forged)
its system. This was not possible before because of the
special material qualities. As well as the PEEK filament with
its printing system, Apium also offers a filament solution
with carbon fibres. This means that filament printing can
also be applied in mechanical engineering and biomedical Composite 3D printing
technology for high-strength components.
The American company Markforged presented the
world’s first FLM system at the end of 2014, with which
fibre-reinforced components can be produced. The
system works with carbon fibre as well as with fibreglass
reinforcement and has a maximum construction space of
320 x 154 x 132 millimetres. The standard version costs
6,500 euros. According to developer information, the
carbon fibre-reinforced components are 40 percent more
stable than comparable components made from ABS. In
addition, they are supposed to have a significantly better
stability-to-weight ratio than those made from 6061-T6
aluminium.
3D printed implant made of PEEK
(Source: Apium Additive Technologies)
19Effect when printing with retroreflective filament
(Source: Kai Parthy)
Reflect-o-Lay
The printing filament developed by cc-Products contains
millions of the smallest reflective pigments. This allows for
the visual effect of retroreflection, which we see in high-
viz traffic clothing, for example, to be transferred to 3D
printed objects. Under normal conditions, the material
appears in its typical grey colour. But if you shine a light
onto it, the rays of light are always reflected back in the
A component printed with a metal filament precise direction they come from.
(Source: Fraunhofer IFAM Dresden)
3D printing filaments from locally produced algae
Metal filament
Over the last six years, the two Dutch designers, Eric
The XERION group, in collaboration with the Fraunhofer Klarenbeek and Maartje Dros, have developed a biocom-
IFAM in Dresden, is currently developing a process to be patible material suitable for 3D printing based on algae.
able to produce metal parts with filament printing. The In the production process, the algae are first cultivated,
plastic-based printing filament is enriched with metal pow- dried and transformed into a printable filament with other
ders; after printing, the excess plastic parts are expelled natural and locally available additives and a biopolymer.
using heat. Subsequently sintering the so-called “green The driving force behind this development was not just
compact” at a high temperature solidifies the component being able to offer an alternative to classic plastic filaments.
and retains the component thickness typical of metal, as Rather, the carbon footprint was the guiding principle,
well as the stability. Here, a significant degree of shrink- as algae absorb CO2 from the atmosphere as they grow.
age must be taken into account. The special feature of
the plan is placing the printer, the oven system and a
mechanical mill in one single unit. All three systems will
have the same controls, including recipe management.
3D printed containers from an algae-based printing filament
(Source: Eric Klarenbeek and Maartje Dros)
20Graphene-based FLM printing Laser wire coat welding
Trend researchers at Frost & Sullivan are expecting 3D An alternative system to laser powder coat welding
printing with filaments to be the next development leap in works with a conventional welding wire. Compared to
the additive manufacturing market. Graphene is a stable powder-based coat welding, working with welding wire
modification of carbon with a two-dimensional structure, offers advantages in terms of the process design, mate-
where carbon atoms are structured in a way similar to a rial utilisation, the quality of the surfaces and the simple
honeycomb. It has a high degree of rigidity and is suit- procurement of starting material. The smallest possible
able as an electrical conductor. Graphene filaments are structure resolution is currently 600 microns. Here, in prin-
expected to have application potential in electronics and ciple, all welding additives available in wire form can be
printable battery systems. processed. In summer 2017, Berlin-based Gefertec GmbH
presented a large-scale system for wire coat welding to
the market. With triple-axis processing, metal components
with a volume of up to 3 cubic metres and a maximum
mass of 3000 kilograms can be produced additively.
Large-scale system for additive wire coat welding
(Source: Gefertec GmbH, Berlin)
212.1.4 Binder jet printing 1 Roller distributes powder
2 Binding agent is applied by the printheads
Binder jetting (historically called 3D printing) was de- 3 Construction platform lowers
veloped at the start of the 1990s by Emanuel Sachs and
Michael Cima at the Massachusetts Institute of Technology 4 Powder bonded via binding agent
(MIT) in the USA with the aim of providing a technology
for use in office environments. Based on the cost struc-
ture for these areas of application, filament printers are
probably more relevant here today. Due to the possibility
5 Printheads for the
of adding colour to the printed components, binder colours black, clear,
Roller Printheads
jetting processes have been used for a vast number of 2
cyan, magenta, yellow
1
application options by private users, for example, when
producing images of people. 4 Workpiece
Construction
platform
3 Powder
Powder storage or powder collection container
3D printing process with a binding agent
As binder jetting is similar to conventional 2D printing,
the technology has proven itself quickly. In comparison
to other additive processes, binder jetting is capable of
achieving very high speeds. In addition, the components
can also be coloured with more than 16 million colours.
Unused powder in the construction space can be reused.
ColourJet printing – 3D printing system (Source: Materialise)
The process Materials
The process is similar to laser sintering and is based Materials based on starch, gypsum or sand and ceramic
on bonding particles with each other. However, unlike composites are the standard materials utilised for binder
selective laser sintering, these particles are not melted jetting. A number of systems manufacturers also supply
with a laser, but rather bonded locally through the use of powders made of various metals for use in dental medicine
a binding agent. The system utilises a printhead which is or offer mixtures for industrial applications and casting
managed by a control unit and moves in layers over the moulds. When working with ceramic or metal powders,
powder bed. It applies droplets of the adhesive substance the object undergoes a sintering process in a furnace
to the newly applied layer of powder. The binding agent after printing. The subsequent infiltration with low melt
penetrates the layer below and binds the new layer of metals fills the pores and increases the density to up to 95
powder with the existing printed geometry. Before start- percent. In order to improve the quality, the process for
ing to generate the next layer, the print bed is lowered metal powder in layer thicknesses of just 25-100 microns
by the thickness of one layer and the process begins could be optimised. It is possible to attain particularly
again. As the component is completely surrounded by high stability with hot isostatic pressing.
powder during the manufacturing process, supporting
structures are not required for protruding elements, just
as during laser sintering. The printed components can
be infiltrated with resin or wax in order to increase their
mechanical strength.
22Component size, precision, reworking Cost-effectiveness
Thanks to the mature inkjet printhead technology, binder The system prices range from between just under 20,000
jetting is one of the fastest additive processes. Systems euros to prices in the six digit range. Therefore, usage in
with a construction space of up to 4 x 2 x 1 meters are now a personal or small-business environment is largely ruled
available (systems manufacturer: voxeljet). A precision out. As a result, there are numerous service providers
of 600 dpi can be achieved. However, the components active on the market who are able to create components
always have a rough surface with visible printing lines at realistic prices.
due to the grain size of the powder used. These can be
reduced through mechanical reworking. For this reason,
current research is focusing on improving the mechan-
ical qualities of the printed components. As a result of Special processes and system types
work carried out at the Fraunhofer Institute for Structural
Durability and System Reliability (LBF) in Darmstadt, new S-Max – Industrial 3D production printer for sand and
material systems and printable inks have been improved metal
to the extent that three-dimensional printing is capable
of achieving similar mechanical strengths to die casting. ExOne is one of the most prominent providers of binder
jetting printers with large construction spaces for shaped
parts made from sand or metals. The S-Max offers a robust
Application and reliable solution for all cold-setting binder systems
in sand printing. It is suitable for almost all cast materials.
Until recently, most small systems capable of tinting with Here, large and complex shapes and cores can be man-
more than 16 million colours were primarily utilised for ufactured even quicker and more reliably. Thanks to the
rapid visualisation during the drafting process. The quiet double job box and the large construction spaces, each
production process and closed system structure make measuring1,800 x 1,000 x 700 millimetres, the S-Max
the process suitable for use in office environments. With produces each prototype requirement as well as whole
large office spaces, binder jet printers are now becoming series with efficiency and a high level of performance.
more widespread in industrial fields of application, for
example in the manufacture of sand grains for foundries.
The printers can also be used for series production. Sand
printing has already been used to manufacture architec-
tonic structures. Metal and ceramic shapes produced using
binder jet printing and subsequently sintered are used in
industrial mould construction, for example.
S-Max large-scale system for industrial binder jetting
(Source: ExOne)
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