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In all cases laser based powder bed systems are marketed as net shaped production technologies.
In addition, ARCAM AB of Mölndal Sweden (www.arcam.com) manufacture and sell the Electron
Beam Melting (EBM) process, which replaces the laser energy source with a high power electron
beam. Although significantly faster than laser based systems, the EBM process works in thicker layer
with a lower X-Y accuracy. Hence, it is more suited to near net shaped parts.
Figure 16 – Accetabular cups used as
replacement hip sockets. Medical grade
Titanium parts manufactured directly on an
ARCAM EBM machine
Figure 15 – Stainless Steel automotive
component manufactured using the MCP
Selective Laser Melting Process
How do powder bed systems compare?
Each of these technologies has its own unique benefits, including materials flexibility, cost of
ownership, the speed of build cycle, cycle time between jobs, build envelope capacity, layer thickness,
part accuracy and repeatability, surface finish and metallurgical properties. Some processes build
within a heater chamber to reduce residual stresses, whilst other build parts onto strong base plates,
which are post process heat treated to remove build stresses. In some processes the parts can
literately be broken away from the build plate, whilst in other processes they require removal using
wire erosion. Figure 17 shows a comparison between the build envelop, layer thickness and energy
source of commercially available powder bed systems.
Manufacturer Process Model
Build Envelope
(mm)
Layer
Thickness
(μm) Energy source (Watts)
MCP Selective Laser Realizer 100 125 dia. x 100 50 50W fibre laser
Melting Realizer 250 250 x 250 x 240 50 100W fibre laser
EOS Direct Metal EOSINT M250X 250 x 150 x 185 20 - 100 250W Co2 laser
Laser Sintering EOSINT M270 250 x 250 x 200 20 - 100 200W solid state laser
M1 Cusing 120 x 120 x 120 20 – 80 100 W solid state laser
M2 Cusing 250 x 250 x 280 20 – 50 200W fibre laser
Concept
Laser Laser Cusing
M3 Linear 300 x 350 x 300 20 – 80 200W fibre laser
PM100 100 dia. x 100 50 – 120 50 or 100W fibre laser
PM100D 100 dia. x 30 20 50W fibre laser
Phenix
Systems Laser Sintering
PM250 250 dia. x 300 20 100W fibre laser
Arcam Electron Beam EMB12 250 x 250 x 180 50 – 200 3,500W electron beam
Melting A2 250 x 250 x 400 50 – 200 5,000W electron beam
Figure 17 – The build volume, layer thickness and energy source of powder bed additive layer manufacturing
processes
Copyright - Econolyst 2008 www.econolyst.co.uk
7
Direct Rapid Manufacturing of Metallic Parts – A UK Industry overview 2008
Where are the current applications for direct metallic ALM technologies?
It would be misleading to suggest that all direct metallic ALM technologies are being used for volume
direct part manufacture, as most of the parts produced are still being used as pre-production form, fit
and function prototypes. This is very much the case in aerospace where the materials and production
processes have yet to be fully validated. However, direct metallic RM has already been validated in
the medial industry for the manufacture of Orthopaedic Implants (as shown in Figure 16), maxiofacial
reconstructive implants (as shown in Figure 5) and surgical cutting guides. Direct metallic RM has also
been used in automotive and motorsport application (as shown in Figure 15) and in the manufacture of
complex tooling cavities and inserts (as shown in Figure 14)
Economics and reality
Direct metallic ALM is expensive. Machine tools range from £200K to almost £1-million, added to
material costs of £80 per Kg for 316L stainless steel up to £475 per Kg for titanium 6-4. Given the
relatively slow deposition rate of some technologies, the resulting parts can seem disproportionately
expensive when compared to cast or even machined parts. However for many users, the geometric
complexity that is possible with RM, coupled with the economics and freedom of tool-less manufacture
are compelling. It should be stressed however, that it is not possible to manufacture all geometries
using these systems. Most notably machines are limited in size. (As shown in Figure 17) Moreover,
certain geometries can cause problems such with residual stress during the build cycle, which can
result in either delaminating or more likely fouling with the powder re-coating system. In truth, operator
experience is the only current way of predicting whether a geometry will make a successful build.
Direct Metallic ALM within the UK
Given the nature and configuration of powder feed systems it is simply not possible to put an exact
　
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