Hybrid manufacturing combines additive and subtractive manufacturing processes within the same machine. This allows parts to be both additively created and machined in a single operation, accelerating production. Direct energy deposition is one additive method used, melting material as it is deposited through a nozzle and then CNC milled for better surface finish and tighter tolerances. Hybrid manufacturing offers benefits like faster time-to-market, ability to produce larger and more precise metal parts than powder bed fusion, and repair of components without producing new parts from scratch. Industries like aerospace and automotive are pioneering the technology.

1. Hybrid Manufacturing
Dr. Prashant S Humnabad
Sir MVIT, Bangalore, Karnataka, India

2. What is Hybrid Manufacturing?
Hybrid manufacturing, refers to the combining of additive and subtractive
manufacturing processes within the same machine.
The use of subtractive and additive technologies together is not a new concept: for
example, post-processing 3D printed parts typically involves CNC machining to
achieve higher accuracy and a smoother surface finish. However, there is also
another way of combining both methods, resulting in what is referred to as hybrid
manufacturing.

3. Hybrid manufacturing leverages the most valuable capabilities of both technologies:
the geometrical complexity of additive manufacturing and the high precision of
subtractive methods. This means that once a part can be additively created and
machined in a single operation, accelerating the production process.
The design of any hybrid component must be done with both additive and
subtractive manufacturing requirements taken into consideration.
Application of hybrid manufacturing
systems is low volume production of
metal parts.
Machines built for this purpose typically
built use a CNC milling system to which
additive capabilities are added, such as
3D printing nozzles, for example (figure).

4. Direct Energy Deposition (DED) is one additive manufacturing method that can
be used in such hybrid solutions.
DED works by melting the material by a laser or electron beam as it is
deposited through a nozzle onto the build platform. The deposited material
can then be CNC milled to achieve a better surface finish and tighter
tolerances.
Alternatively, a part can be milled first and then extra features additively built
to create more complex shapes. DED technology is an ideal option for
producing large metal parts and repairing key components.

5. US-based company Hybrid Manufacturing Technologies was the first to develop
a hybrid deposition and milling system named the AMBIT™ in 2013.
The most distinctive feature of the AMBIT system is its patented deposition
heads which can be added to any CNC machine to produce new or repair
existing parts, with an automated changeover process.
DMG MORI is another key player in the field of hybrid manufacturing. Its
LASERTEC 65 3D hybrid machine offers a 5-axis material deposition nozzle,
enabling highly complex metal parts to be produced.
US-based Optomec company offers two hybrid solutions based on its
proprietary LENS technology.
(Firstly, its series of hybrid additive machines, the newest of which (the LENS
850-R system) is suitable for large metal parts, and secondly its machine tools
series, which can be integrated into a standard CNC platform.)

6. Benefits
Lead times for metal part production can be sped up, resulting in a faster time-to-
market.
Build highly precise, dense metal parts in larger sizes than powder bed fusion processes
would allow.
Building a part in any direction without the need for support structures is possible.
Different metals can be used in the same part. For example, a hybrid system can start with
machining a block of one metal and then switch to another using additive manufacturing. Often
cladding is accomplished with this way.
Laser sintering can also be coupled with CNC milling, resulting in a hybrid powder bed
process. Matsuura Machinery Corp. is the major manufacturer of such systems, offering its LUMEX
series of “metal laser sintering hybrid manufacturing” machines.

7. By combining selective laser sintering and a machining platform which
accommodates as many as 20 tools (the LUMEX Avance-60), LUMEX systems
can produce parts without subsequent finishing. The machining spindle
featured in the systems is also capable of reaching internal structures as they
are printed, creating highly accurate parts. This wouldn’t be possible with
additive manufacturing alone, during which a part is printed first and then sent
to finishing.
According to Matsuura, this hybrid technology is particularly beneficial for the
mould-making industry, as it is capable of reducing manufacturing costs of
moulds and dies to half when compared with conventional methods. However,
other industries can also take advantages of the powder bed hybrid
technology, creating high-value components with reduced weight and
improved functionality.
Additionally, moulds with complex conformal cooling channels can be
additively manufactured and then machined with a powder-bed hybrid AM
machines, resulting in 50% faster injection mould runs whilst improving tool
life by more than 30%.

8. Applications
Aerospace and automotive industries are pioneering hybrid manufacturing technology (these
industries typically have one-off or small batches of highly complex parts undergoing frequent
iterations).
While hybrid manufacturing systems have not yet been developed specifically for medical
applications, 3D printing medical parts and subsequently machining them is already a widely used
process within the industry.
However, with the advent of hybrid manufacturing, highly precise patient-specific prosthetics
and dental implants could be produced even faster and more cost-effectively.
However, hybrid additive manufacturing is perhaps even more beneficial in the field of repair and
maintenance operations. One example is GE, which has used Hybrid Manufacturing Technologies’
hybrid system to repair turbine blades.
By hybrid manufacturing, worn-out features and damaged parts of a turbine blade can be repaired
by depositing new material on its surface and then machining it to precise tolerances.
This not only eliminates the need for producing a new part from scratch but also reduces the
number of steps required to repair a part.

9. The Road Ahead
While hybrid manufacturing is still in the early stages of development, the benefits it
could offer to the manufacturing industry are endless, from shorter lead times to
complex parts that would otherwise be impossible to create.
There is a lot of research being conducted in the field: for example, Loughborough
University is pioneering what it calls hybrid and multi-systems AM for metal and
polymer systems.
Ultimately, hybrid technologies could become an industrial game-changer, paving the
way for more sustainable, all-in-one manufacturing.