Tech Briefs Magazine - December 2021 - 19

hybrid manufacturing process, as well as
some real-life manufacturing application
examples in which the DED process
is already in use and providing manufacturers
with key benefits.
Application Examples
The subsequent DED applications are
broken out by market segments including
Aerospace, Automotive, and Medical.
Aerospace. Aerospace manufacturers
have been using the DED process for
several decades to perform blade
repair. Repair processes continue to
expand as DED technology improves.
What's new is the usage of the DED
process to build the parts themselves.
Cost savings are achieved due to a better
buy-to-fly ratio, especially for expensive
and difficult-to-machine alloys
where there is a significant reduction of
both the cost of the raw material re -
quired and the amount of material to
machine out afterward.
DED adds flexibility to the manufacturing
process by easily enabling design
variations. For example, DED processes
can be used to build part variants on
demand and requires minimal tooling,
so there is a reduction in the number of
components used in the manufacturing
process. With the DED process, it is also
possible to build parts with composite
and functional graded materials.
Automotive. The tooling used by the
automotive industry is one obvious segment
where an automated DED process
can advantageously replace a manual one.
Car manufacturers have already experimented
with extending the life of tooling
(to last three times longer) by rebuilding
wear sections with a harder alloy. Cost savings
can also be found by modifying existing
expensive tooling to produce new
parts. For special car models, it is possible
to add material on existing standard parts,
avoiding the need to have a new setup to
produce those parts. Finally, fast tooling
repair can keep the assembly line in production
and avoid costly and counterproductive
downtime.
Medical. Because each human body is
different and unique, customized parts are
required when making implants or fixtures
for medical applications. Medical manufacturers
recognized this quickly and took
advantage of various possibilities offered by
the powder bed additive processes. The
DED process can also help here to produce
better parts by coating some areas with a
dissimilar material to prevent wear or by
reinforcing highly stressed areas.
Tech Briefs, December 2021
Cov
As seen on the various aerospace, automotive,
and medical application images
featured here, the additive pro cess is not
generally being done on a flat area of the
part. The DED process provides benefits
when building models of any shape,
compared to the Powder Bed Fusion
process where the build occurs layer by
layer. DED can also be applied to more
complex geometry and without designing,
building, and removing supports
that are required in Powder Bed Fusion.
Implementing the DED
Process
First, it is important to confirm that
your CAM software has the needed functionality
for additive and hybrid processing.
A second important factor is to
establish on which type of equipment the
DED process will be performed. Ma -
chine tool manufacturers have started to
offer additional equipment enabling the
DED process. These machine tools are
expensive and often have additional
devices such as lasers, powder delivery
systems, etc. for the additive process.
Other machines are focused exclusively
on additive processes.
CAM Software and Hybrid. Selecting reliable
CAM software is critical to success
and the following questions need to be
addressed. Is the software capable of
working within a hybrid process? Are you
able to create machining and additive
operations in the same programming
environment? Are the operations limited
to planar slices or can 3D sections be
used for build layers? How does the software
keep track of the stock between different
types of operations? The stock
tracking is very important if performing
multiple operations in the same setup
and/or additional operations. The stock
model should also be capable of being
used for toolpath generation and for collision
check with the tool assembly,
machine components, etc.
5-Axis. As mentioned in the previous
application examples, the DED process
will most likely not happen on flat surfaces.
Since the best conditions for the
build process are normal to the base surface,
5-axis trajectories are beneficial
when applying material on shaped components.
Another reason why 5-axis is
key is that the additive device might
need to be tilted to avoid existing features
or to access challenging areas.
While smoothness of the 5-axis motion
is a big factor in the machining perfor -
mance and surface quality of a part, it is
also critical for DED. CAM software plays
a significant role in the 5-axis path generTrimming
die repair (chipped edge): The deposition occurs in 5-axis, to stay as normal as possible
to the substrate. Considering the initial and damaged part geometry, the CAM system adds material
only where it's required. Subsequent pre-finishing and finishing operations take place on the
same hybrid system.
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Tech Briefs Magazine - December 2021

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