Page 27 - Plastics News January 2021

FeAtures

Additive manufacturing ..

Additive manufacturing is the process of applying over other types of additive manufacturing. The process
3D-printing to industrial production that allows materials is applied in industries such as heavy machinery,
to be created without joints and with minimal post- construction, mining, and aerospace to make large, low-
processing. Multiple materials can be used during this volume parts.
process, which makes it easy to create new products with
minimal waste and lower materials costs. Binder Jetting
Binder jetting additive manufacturing uses an ink-jet print
Seven process of additive manufacturing head to print a binder onto the powder which “binds” the
There are seven additive manufacturing production metal particles together into a green state. The parts are
techniques. Each vary due to materials, layering, and then removed from the powder bed and must go through a
machine technology needed. EWI specializes in all seven, debinding and sintering process (in an oven) to make the
and can help your team identify, design and implement parts fully dense and hard. Parts typically shrink 20-25%
the process that’s right for your application. during the sintering process.

Powder Bed Fusion Sheet Lamination
This type of additive manufacturing uses either a laser or This type of additive manufacturing binds sheets of
electron beam to melt and fuse material powder together material to form a part. There are two types of sheet
to develop products. Here are the differences between lamination additive manufacturing:
the two types of powder bed fusion :
Ultrasonic Additive Manufacturing – This type of sheet
Laser Powder Bed Fusion – In laser powder bed fusion, lamination uses ultrasonic vibrations to weld metal tapes
a laser is used to heat material in a powder form into together until it is able to form objects.
3D products. After a layer of powder has been indexed Friction Stir Welding – Using friction stir welding enhances
down, a new layer of powder is spread to continue the material properties as each layer is stirred. This creates
process. Ultimately, laser powder bed fusion does not diffusion and reduces the grain size for a secure bond.
require support.
Electron Beam Powder Bed Fusion – This type of powder Material Extrusion
bed fusion is used to melt particles together in specific In material extrusion, a filament or thermoplastic material
areas. The beam can be manipulated very fast, which is used to create parts. With this process, the filament (or
speeds the overall process by allowing multiple melt pools thermoplastic) is heated and then continuously layered
to occur simultaneously. through a nozzle to create the final product or part.
New materials are available that have metal filler inside
Directed Energy Deposition the plastic “rods” that are extruded. The parts then go
In directed energy deposition (DED), powder or metal wire through the debinding and sintering step like binder jetting
is used with an energy source to add material or fuse a to make metal parts.
material onto an existing part or to create a new part.
Here are the three types of directed energy deposition: Material Jetting
This additive manufacturing process New materials
Laser DED – Laser DED deposits powder onto the build are available that have metal filler inside the plastic
while being melted by the laser at the same time. “rods” that are extruded. The parts then go through the
This process can generate much faster build rates over debinding and sintering step like binder jetting to make
conventional laser powder bed fusion.
metal parts.
Arc DED – An EWI specialty that is more dynamic than other
additive manufacturing processes. Arc DED is suitable Vat Photopolymerization
for large builds. An advantage for manufacturers is that Unlike the other types of additive manufacturing, vat
existing arc-welding robots and power supplies. photopolymerization uses liquid resin. This photopolymer
resin is applied layer by layer and then a UV light hardens
Electron Beam DED – EB-DED enables the manufacturing the resin to create the final part or object.
of large parts extremely fast, which gives it an advantage

27 Januar y 2021 Plastics News