Exploring Additive Manufacture in Power Generation Devices
M. Kaner, C.P. Purssell and S.J. Leigh
School of Engineering, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL
M.Kaner@Warwick.ac.uk
Introduction
Additive Manufacturing (AM), often also referred to as 3D printing, is a
term used to describe the production of objects directly from
computer-aided designs through the selective addition of materials
layer-upon-layer, rather than through subtractive processes such as
machining from solid, moulding or casting. This approach means that
there are no significant pre-tooling requirements and designs can be
incrementally varied without re-tooling. Thus, objects can be produced
in a ‘mission-specific’ fashion, without the need for new tooling for
each design.
One area receiving increased recent attention is in the incorporation of
electrical circuitry inside components during 3D-Printing processes.
Incorporating circuits inside an object during manufacture can ensure
optimum placement to achieve the desired functionality. [1]
One useful electrical component that can be incorporated into a
component is an electrical coil. Coils are found in various
electromechanical devices from motors, generators basic inductors or
MRI machines.
As such, the production of a coil using 3D-Printing technology was
identified as a key gateway technology to the manufacture from
actuators, such as motors and solenoids to bespoke power generation
components.
Fig. 1 – An example of
how coils are used in
electric motors. [2]
This picture shows an example in which coils are used within electric
motors . The produced coil can be tested by passing a current through
the coil and measuring the magnetic field generated without it. If the
generated magnetic field is greater WITH the core than without, then it
can be confirmed than an electromagnet has been created successfully.
Results & Discussion
Coil
Previous methods such as coextruding copper conducting wire through the 3D
Printer’s nozzle were unsuccessful as there were clear geometrical limitations
with the number of turns the coil could have [1]. so a new method which is novel
to this particular application was used. A coil with a larger number of turns
gives a stronger magnetic field. In order for a coil to be operational, adjacent
turns of the copper conducting wire must not touch otherwise the coil
short circuits and is rendered non-operational. By using
Additive Manufacture a rotational print bed was used and
the wire were coextruded with a plastic such as PLA or
ABS such that they are insulated from each other and at
regularly spaced intervals. G-Code was written to ensure
optimal spacing without compromising the coil’s
structural
integrity.
Fig. 3 - Photo of
Printed Coil
Previous methods attempted to feed the copper conducting wire through the 3D
printing nozzle such that the wire is coextruded with the plastic out the nozzle. [1]
This method was unsuccessful due to limitations of how small the hole in the side
of the nozzle could be and therefore how small the diameter of the wire had to
be. The cross section of the wire turned out to be too small to overcome back
pressures of the plastic being extruded from the nozzle and so was unsuccessful.
This new method, ensures the copper wire is extruded with the plastic by feeding
the wire in after extrusion, but while the plastic is still molten. A coil with 12 turns
and ten layers was then produced. The nozzle was also redesigned in order to
ensure the wire is in the middle of the printed insulation
Iron Core
Pellets of ABS are mixed into Acetone and DCM
into a slurry before adding Iron powder. This
mixture is dried out and extruded through an
extruder many times. This process of extruding and
re-extruding is known as a ‘pass through’.
Fig. 4 - Photo of Printed Core
Aims and Objectives
• A1 – To be able to produce an electrical generation device using 3DPrinting
• O1 – To be able to print an electrical coil
• O2 – To demonstrate a working electrical coil by producing a simple
electromagnet.
Diagram of Apparatus/Methods
•
A bespoke 3D-Printing system was used in order to produce the
electrical coils.
Copper Wire
Extrusion
Head
Needle
Spindle
Nozzle
Fig. 2 – Diagram of
Apparatus/Methods,
showing the setup.
•
The system consisted of a copper wire on a spindle being fed
through a needle resting on the nozzle contained by the extrusion
head. This system was attached to the printer such that it moved
with the extrusion head. As the molten plastic is extruded, the
copper conducting wire ‘catches’ onto it and is wound around a
cylindrical print bed as it rotates.
Electromagnet
Fig. 5 –
Diagram of
Assembled
Electromagnet
Fig. 6 – Graph Showing Magnetic Field Strength
Against Arrangements of Core & Coil
Current was passed through the electromagnet and the electric field
surrounding it was measured by programming a microcontroller and placing the
coil on top of the magnetometer. It can be seen that the strength of field WITH
the core is greater than that without the core which are the results expected.
Summary and further work
3D-Printing processes are stimulating innovation in component design,
enabling the manufacture of parts that cannot be made by traditional
methods and are stimulating alternative business models and supply chain
approaches such as localised manufacture and on-demand production.
Recently, there has been increased interest in the utilisation of 3D-Printing in
the manufacture of complex functional parts, beyond simple concept
prototypes. Already at Warwick we have demonstrated the use of 3D-Printing
with advanced materials for the manufacture of products with embedded
sensing capability.
References
[1] – Bayless. J et al (2010). Wire Embedding 3D Printer. Eng. Phy. University
of British Columbia
[2] - http://www.movingmagnet.com/, Date last accessed 05/10/2015 at
12:52