Page 19 - Electric Drives and Electromechanical Systems

Chapter 1 Electromechanical systems 11

FIG. 1.5 The implementation of the Fused Filament Fabrication and Polymerisation additive manufacturing
processes. (A) Fused Filament Fabrication: the nozzle mechanism draws material from a reel, and after melting,
deposits it on the built table. The build table is lowered to allow the next slice to be deposited. (B)
Polymerisation: the object is printed using a photopolymer resin. The laser is used to solidify the resin to form the
printed layer, after a layer is printed, the build platform is lowered to allow the next layer to be printed.

converted to a standard additive manufacturing file format - usually an STL (stereo-
lithography) file, the file defines series of closed polygons that correspond to the
different layers that are to be printed. Once the required manufacturing data has been
generated it is down loaded to the process machine. Finally, the additive manufacturing
machine builds the model layer by layer. The layer thickness dictates the final quality
and depends on the machine and process. For Fused Deposition Modelling a layer
thickness of 0.254 mm is typical, Polymerisation can generate layers of thickness in the
range of 0.05e0.1 mm. After printing, the object may require additional cooling and
curing periods prior to cleaning or machining to finalise the production process.
The advantages of the additive manufacturing process give the designer significant
design flexibility. Additive manufacturing allows objects to be printed in one single
process. As the constraints of subtractive machining are removed, together with the
production of specialist tooling, very complex shapes to be produced. Additive
manufacturing will bring significant benefits to many areas, for example in medicine
where prosthetic parts can be fully customised to the patient and their individual
requirements, at substantially reduced cost (Bose et al, 2013).
Additive manufacturing has significant cost benefits, including reduction of material
used, the additive manufacturing process use the same amount on material as in the object
produced, with zero scrap. As the design is in electronic format, it can be transmitted to a
remote machine, this reducing transport costs and allowing, in particular, when spare parts
for ships or aircraft are required at a remote location (Chekurov et al., 2018).