Printing Conductive and Non-Conductive Materials Simultaneously

Printing Conductive and Non-Conductive Materials Simultaneously
Printing Conductive and Non-Conductive Materials
Simultaneously on Low-End 3D Printers
Sander Klomp
Supervisors: Prof. Jelle Saldien, Cesar Vandevelde
Master's dissertation submitted in order to obtain the academic degree of Master of
Science in de Industriële Wetenschappen: Industrieel Ontwerpen
Department of Industrial System and Product Design
Chairman: Prof. Kurt Stockman
Faculty of Engineering and Architecture
Academic year 2014-2015
Printing Conductive and Non-Conductive Materials
Simultaneously on Low-End 3D Printers
Sander Klomp
Supervisors: Prof. Jelle Saldien, Cesar Vandevelde
Master's dissertation submitted in order to obtain the academic degree of Master of
Science in de Industriële Wetenschappen: Industrieel Ontwerpen
Department of Industrial System and Product Design
Chairman: Prof. Kurt Stockman
Faculty of Engineering and Architecture
Academic year 2014-2015
Foreword
This thesis is written as a Master's dissertation submitted in order to obtain the
academic degree of Master of Science in de Industriële Wetenschappen: Industrieel
Ontwerpen.
The subject of this thesis was chosen from both personal interest and the fact that
3D printing in general is a current topic, which promises for an interesting evolution
in the future.
At the beginning of this thesis I had little knowledge about 3D printing. However, I
have been able to achieve a result I am very satisfied with.
I would like to thank my supervisors from the University, Cesar Vandevelde and Jelle
Saldien for giving me the opportunity to work on this project. Their valuable insights
and directions gave me needful guidance to complete the research and write this
thesis.
I would also like to thank Maarten Vanhoucke, researcher at the Industrial Design
Center in Kortrijk to share his knowledge and the best available information about 3D
printing and electronics.
Last but not least I want to thank Gianni Franci for sharing the design files of his dual
extruder system and to guide me through the process of installing and modifying it.
The author gives permission to make this master dissertation available for
consultation and to copy parts of this master dissertation for personal use. In the
case of any other use, the copyright terms have to be respected, in particular with
regard to the obligation to state expressly the source when quoting results from this
master dissertation.
Sander Klomp
Kortrijk, June 2015
Abstract
This thesis explores the possibilities of printing conductive and non-conductive
materials simultaneously on low-end 3D printers with the intention of demonstrating
the potential and to stimulate further use of the technique.
3D printing has evolved in the past decades from being a sophisticated process
requiring expensive machinery used only by larger companies to a considerable
number of relatively cheap open source projects allowing for the technique to be
used by a much wider audience. Today the average person can buy a 3D printer,
draw a part in CAD or download one from the Internet and start printing it on his
desktop 3D printer in the comfort of his home. With the coming of new printable
materials the opportunities grow and the whole concept of manufacturing and
customization changes. The development of printable, electrically-conductive
materials opens up a broad avenue in the possibilities of the technique, not only
does it allow the printing of sensors and circuits, it could change the whole standard
of electronic devices now being able to work in a three-dimensional space instead of
using the classic printed circuit board.
This thesis describes the process we went through upgrading two low-end 3D
printers to print two materials simultaneously. Afterwards we describe how this
technique can be used for printing conductive and non-conductive materials
simultaneously and we give a few demonstrations of the possibilities.
Extended Abstract
(See next pages)
Printing Conductive and Non-Conductive Materials
Simultaneously on Low-end 3D Printers
Sander Klomp
Department of Industrial System and
Product Design,
Ghent University, Campus Kortrijk
Marksesteenweg 58, 8500 Kortrijk,
Belgium
[email protected]
Cesar Vandevelde
Department of Industrial System and
Product Design,
Ghent University, Campus Kortrijk
Marksesteenweg 58, 8500 Kortrijk,
Belgium
[email protected]
Abstract—3D printing has evolved in the past decades from
being a sophisticated process requiring expensive machinery used
only by larger companies to a considerable number of relatively
cheap open source projects allowing for the technique to be used
by a much wider audience. Today the average person can buy a
3D printer, draw a part in CAD software or download one from
the Internet and start printing it on his desktop 3D printer in the
comfort of his home. With the coming of new printable materials
the opportunities grow and the whole concept of manufacturing
and customization changes. The development of printable,
electrically-conductive materials opens up a broad avenue in the
possibilities of the technique, not only does it allow the printing of
sensors and circuits, it could change the whole standard of
electronic devices now being able to work in a three-dimensional
space instead of the classic printed circuit board. This research
paper explores the possibilities of simultaneously printing this
new conductive material and non-conductive materials on lowcost 3D printers.
Keywords — 3D printed electronics, additive manufacturing,
conductive material
I.
INTRODUCTION
Printed circuit structures
To many of us, a world without electronic
devices is very hard to imagine. Electronics have
changed nearly every aspect of our lives. Today,
nearly all circuits use discrete components that are
placed on a flat, two-dimensional printed circuit
board (PCB). With a big increase in popularity over
the past few decades additive manufacturing or 3D
printing could change the way we build electronic
devices in the future. Instead of using PCBs that are
mounted afterwards in the device, Printed Circuit
Structures (PCS) would look at electronics from a
new perspective. In a PCS the enclosure and
structure of the device itself would carry the circuits
and components making the usage of PCBs
unnecessary. In this approach components can be
smoothly integrated and even hidden inside the
structure. By building the electronics into the
A.
Jelle Saldien
Department of Industrial System and
Product Design,
Ghent University, Campus Kortrijk
Marksesteenweg 58, 8500 Kortrijk,
Belgium
[email protected]
structure the device would become more rigid,
eliminating the use of glue, snaps, solder, wiring or
bolts. This would also result in the ability to use
much more components in far less space, making it
possible to create smaller and less bulky devices
while not sacrificing in their functionality [1]. We
are evolving into a world where all electronic
devices become smart and communicate with each
other. With the coming of 3D printing conductive
materials it will be possible to print functional
components and sensors like 3D touch surfaces,
integrated bend or turn sensors, optimized antennas,
custom motors, speakers, solenoids and much more
that can be integrated in smart devices and
communicate through ‘the Internet of Things’ [2].
3D printing
3D Printing or Additive Manufacturing (AM) is a
rapid prototyping technique that lets users
physically create three-dimensional (3D) objects
drawn with a computer. The object is usually
modelled with computer aided design (CAD)
software and exported as a Surface Tessellation
Language (STL) file. Slicing software slices the part
in two-dimensional layers, which are sequentially
printed on top of each other to create a solid object.
As opposed to subtractive manufacturing (SM), a
technique that takes a raw metal and creates a part
by cutting or drilling sections away, additive
manufacturing is less expensive, less time
consuming and produces much less waste material.
There are a few different techniques for 3D
printing. The two techniques that are most used in
low-cost 3D printers are Fused Filament Fabrication
(FFF) and Stereo Lithography (SLA).
B.
Fused Filament Fabrication
FFF is equivalent to Fused Deposition Modelling
(FDM), a term and abbreviation that is trademarked
by Stratasys Inc [3]. The term fused filament
fabrication (FFF), was invented by the members of
the RepRap project to provide a term that would be
legally independent in its use [4]. An FFF 3D printer
extrudes a thermoplastic material through a
temperature-controlled nozzle similar to how a hot
glue gun extrudes a melted cartridge of glue. The
nozzle heats the material to a semi liquid state and
draws the outline in ultra thin layers (typically
between 0.05 mm to 0.3 mm) onto a build platform.
Then it fills the outline with a raster of material
creating a complete section of the object and
proceeds to the next layer binding it to the previous
one. The result is a plastic 3D model built up one
layer at a time. Because sometimes not all the layers
are touching the build platform a support structure
can be created which can be removed after the print
is finished. Because the printed parts are relatively
strong and durable this technique is ideal for
functional prototypes and the quick testing of shapes
and fittings [5].
1)
layers that solidify on top of each other form the 3D
object. Similar to FFF sometimes supports are
required for overhangs and holes, these can be added
either manually or automatically. After the product
is removed from the build platform the support
structure can be removed.
Fig. 2. Schematic overview of the Stereolythography process [6]
State of the art
A three-dimensional accelerometer sensor system
with microprocessor control (Fig. 3) was fabricated
using a previously developed integrated layered
manufacturing system that combines conductive ink
dispensing with SLA. The insert itself was printed
using SLA and after cleaning it rigorously, the ICs
and discrete components were inserted into their
designated cavities. Conductive silver ink was then
dispensed throughout the design to create the circuit
interconnections. After the conductive silver had
cured in a convection oven, the antenna and ground
plane were coated with the silver ink and again the
insert was placed into a convection oven for final
curing. The insert is press-fit into a helmet for the
purpose of detecting Traumatic Head Injury (THI)
when excessive acceleration to the head is measured.
Applications could include monitoring the health of
soldiers or athletes [7].
C.
Fig. 1. Schematic overview of the Fused Deposition Modeling process [4]
Stereolithography
Stereolithography (SLA) (Fig. 2) uses a laser
beam to harden the surface of a vessel of liquid resin
to create a part. Where the laser beam hits the liquid,
the hardening takes effect. When a layer is finished,
the platform that holds the object drops a fraction of
a millimetre deeper into the vessel. The different
2)
Fig. 5. Quadcopter produced almost entirely on Voxel8 Developer’s Kit [9]
Fig. 3. Accelerometer System Helmet Insert [7]
The Voxel8 Developer’s Kit (Fig. 4) is an
‘electronics 3d printer’ that combines an FFF
machine with a conductive ink dispenser. The
machine starts out printing just like any other FFF
3D printer. For placing circuits into an object, a
second nozzle is utilized, which is filled with highly
conductive silver ink. Once the circuits are printed,
the printer switches back to the FFF material. The
machine pauses when an electrical component needs
to be placed. The build platform can be removed and
components like LED’s or sensors can be placed in
place. Once placed, the machine resumes the print
job [8]. At CES 2015, the company displayed a quad
copter that was produced almost entirely in one
piece on their machine. The PLA and connective
circuits of the quad copter were 3D printed in one
go, with the electronics, battery, and motors inserted
throughout the printing process [9].
Carbomorph, a mixture of conductive Carbon
Black (CB) and polymorph is a fairly new simple,
low-cost conductive composite material able to be
printed with a low-cost FFF 3D printer. The piezoresistive nature of the conductive composite was
already used to sense mechanical flexing when
added to an existing object and was also embedded
into an ‘exo-glove’ interface device for sensing the
flexing of a hand. The material was also used to
create an embedded capacitive sensor in a smart
vessel (Fig. 6), which is able to sense the amount of
liquid placed inside. The printed sensors are simple
to interface to and require no complicated electronic
circuits or amplification and can be monitored using
existing open-source electronics and freely available
programming libraries [10]. Today Carbomorph is
finding its way to the market or people even claim
they improved the formula and try to crowd fund
their developments using Kickstarter campaigns.
Many have tried but few have succeeded. Esun,
Proto-Pasta, Makergeeks, 3dxtech and Zentoolworks
are a few examples of manufacturers of this
conductive filament.
Fig. 4. Voxel8 Developer’s Kit [8]
Fig. 6. 3D printing of capacitive ‘smart’ vessel [10].
II.
METHOD
3D printers
We decided to focus our research on printing
with low-cost FFF machines. The 3 different
printers we used were an Ultimaker Original
(UMO), an Ultimaker 2 (UM2) and a RepRap Prusa
I3. The UM2 was mainly used to print parts for
upgrading the other two printers. This section will
give an overview of the upgrades we made.
A.
Ultimaker Original (UMO)
The UMO (Fig. 7) is a Cartesian FFF 3D printer
that uses 3mm filament and can print a number of
different materials. The printer is well known in the
Maker Community to be a ‘hackable’ printer, since
it mostly uses simple laser cut or printed parts and
open source software running on an Arduino Mega
board. In 2012, the Ultimaker Original was awarded
‘Fastest and Most Accurate 3D printer available’ in
MAKE Magazine's annual 3D printing guide [11].
For our research we did some upgrades and
alterations to the printer. We installed a heated build
platform, shield windows and a dual extruder.
1)
results in a higher quality finish with materials such
as ABS and PLA. A HBP also allows users to print
without rafts, skirts and brims [13]. The heated
build platform we installed (Fig. 8) is a kit we
obtained from a vendor on EBay. It features a 3 mm
aluminium core PCB with an integrated PCB heater,
LED indicators and thermistors that allows for fast
heating (20°C to 100°C in less than 5 minutes). The
kit contains a power supply, which we installed to
provide power to both the printer and the bed. To fit
the power supply we provided the printer with some
raising feet so the supply could fit snugly in the
bottom of the printer next to its electronics. We also
replaced the 4-point levelling system of the bed
with a much easier 3-point levelling system.
Fig. 8. Heated build platform
b) Shield
Fig. 7. Ultimaker original [12]
a) Heated
build platform
A heated build platform (HBP) improves printing
quality by helping to prevent warping. When the
printed plastic cools down, it has the tendency to
shrink. Because the sides of the object cool faster
than the inside, mainly while printing in ABS,
sometimes warping occurs. Because of this warping
the corners of the part tend to come loose from the
build platform. When a HBP is installed the printed
part stays warm during the printing process
allowing the shrinking to happen more evenly. This
windows
Because we wanted to be able to print with ABS
we installed shield windows to make the printer case
more enclosed. Extruded ABS is very sensitive for
drafts in the environment surrounding it. When it
doesn’t heat up or cool down evenly problems like
warping or deformed parts might occur [14]. The
shield windows we installed (Fig. 9) were made of
laser cut 3 mm acrylic sheets with a 5mm overlap on
the sides. 8 corner pieces were designed and 3D
printed to keep the sheets in place. The design was
also shared on Thingiverse.
Fig. 9. Shield windows
Dual extruder
In order to be able to print two materials, being it
conductive
and
non-conductive
or
not,
simultaneously we added a dual extrusion system to
the Ultimaker Original. Dual extrusion is a
technique already used by professional 3D printers
to generate support structures. Since the beginning
of the RepRap project [15] people in the community
have tried to implement the technique in the lowcost machines but this has proven to be fairly
difficult. As of today only a handful of companies
offer dual extrusion on their low cost FFF printers
and these systems are still known to have quite a bit
of flaws. The most common problems the systems
have are ‘oozing’ and nozzle alignment. When a
nozzle is inactive, it stays hot and this causes the
material inside to leak out of the nozzle cluttering
the print, this phenomenon is known in the Maker
Community as ‘Oozing’ (Fig. 10). When using a
dual extrusion system both nozzles have to be at
exactly the same height. When one nozzle is lower
than the other it will scratch the print or pull it off
the build platform (Fig. 11). If one nozzle is higher
than the other two materials printed on top of each
other will not bind properly. Professional 3D
printers that use the technique have much more
control over the process because they use heated
chambers and printing materials supplied by the
same manufacturer. Ultimaker also sells an
‘experimental’ upgrade for the UMO and was
planning to develop a dual extrusion upgrade for the
UM2 as well but in a company update released on
their community forum [16] they announced they
cancelled the development of the upgrade due to
technical difficulties.
c)
Fig. 10. Oozing effect of the inactive nozzle
Fig. 11. Print being pulled loose by inactive nozzle.
We decided to use E3D’s V5 all metal hot ends
(Fig. 12) because we already used these for single
extrusion on the UMO and have had better results
with them than the standard UMO hot ends. Because
some types of filaments are only available in certain
diameters we chose to use a combination of a 3 mm
and a 1.75 mm hot ends which would allow us to
also print with these two different types of filament
diameters. The design of the dual extruder (Fig. 13)
consists of an XY-carriage 3D printed in ABS. In
this carriage both hot ends are mounted and can be
adjusted in height separately by loosening the front
mounting bracket. On the backside two 30x30x10
mm fans were mounted to cool the heat breaks, this
is necessary to keep the transition zone between the
glass transition temperature and the melting
temperature of the materials used as small as
possible in order to reduce friction problems. On
each side of the carriage there is a mounted fan duct
that holds two 40x40x10 fans to actively cool the
print area, this is particularly useful when printing
bridges or small details in PLA. The two extruder
motors were mounted on the back of the printer and
connected to the hot ends via ‘Bowden tubes’. The
Bowden tube reduces the moving mass of the
extruder resulting in faster controlled motion, less
shaking of the machine, less energy use and faster
printing. The system has one major drawback:
hysteresis. The plastic filament will compress
in any extruder, but putting pressure on such a long
length of filament will multiply the effects of this
compression, leading to springiness. The flexibility
of the PFTE tube increases this problem. It’s
possible to control this problem with software
calibration [17]. Because we are using two different
sizes of nozzles the extruder motors both need to
have their own feeding speed, the speed the extruder
motor is set to in order to push the material through
the nozzle. This was not possible with Marlin, the
standard firmware of the Ultimaker Original. We
opted for installing ‘Repetier Firmware’, another
firmware solution that made it possible to assign
different feed rates to each extruder. By installing
the new firmware some other problems appeared;
the display stopped working and the pins had to be
re-assigned in the firmware, it was not possible to
slice with ‘Cura’, Ultimaker’s standard slicing
software, anymore because the program wouldn’t
recognize the different feed rates. The solution to
this problem was using ‘Repetier Host’ a slicing
program made by the same developers of the new
firmware we installed.
Prusa I3
The Prusa I3 (Fig. 14) is the third iteration of the
Prusa mendel, which was developed as a RepRap
[15] project. This project started the 3D printer
revolution by building low-cost, self-replicating,
open-source 3D printers. It has become the most
widely used 3D printer among the global members
of the Maker Community (Fig. 15). The frame of
our model was made of a single sheet of aluminium
and uses a RAMPS 1.4 controller. It’s also a
Cartesian printer and the main difference between
this printer and both Ultimaker printers is that this
printer moves the build platform for the Ymovement where as the Ultimaker moves the print
head itself. This printer also doesn’t feature an
enclosed frame making it less ideal to print ABS.
We upgraded this printer with a dual extrusion
system.
2)
Fig. 12. E3D V5 all metal hot end [18]
Fig. 14. Prusa I3 Metal Frame [19]
Fig. 13. Dual extrusion system mounted on the UMO
Fig. 15. Diamgram of 3D printer usage [20]
a) Dondolo
Dual Extruder
While looking for other dual extrusion systems
after what we had learnt from using our design on
the UMO we came across a design shared on
Thingiverse made specificly for the Prusa I3. It
looked promising, using a similar technique as seen
in the professional Stratasys Dimension printers
[21], allowing the hot ends to pivot around an axis.
The design uses a servomotor to make the hot ends
pivot around the axis. The axis used as a pivot point
is the axis of the single stepper motor driving the
extrusion for both hot ends. The design was
originally developed for E3D’s V6 all metal hot
ends but after some minor modifications we were
able to make it work for the V5 hot ends as well. To
reduce complexity in firmware settings we decided
to use two hot ends for the same 3mm filament
diameter. For the extruder motor a stepper with high
phase resistance and inductance was needed while
still remaining a high torque. The NEMA17
42BYGHW208
stepper motor met these
requirements. To drive the stepper motor we also
upgraded the printer with a new DRV8825 stepper
driver. Because we needed a very sharp drive gear to
feed the filament we made one ourselves using a
8mm rod, which we provided with teeth on a milling
machine. Later we used a UM2 drive gear, which
proved to give better results.
Fig. 16. CAD visualisation of the Dondolo dual extrusion system
Printing Materials
1) PLA
Polylactic acid (PLA) is a biodegradable polymer
that is made from lactic acid, a natural substance
gained from corn crops making it ideal for usage in
the poorer counties of the world and a non-toxic and
renewable resource. PLA biodegrades in
approximately 60 days while other plastics can take
up to 400 years to degrade [22]. The material is
harder than ABS and has significantly less shrinking
problems. It melts at a relatively low temperature
(around 180°C to 220°C), and has a glass transition
temperature between 60-65 °C, making it a very
useful material. When printing PLA it is important
to keep the distance between the glass temperature
point and the melting point as small as possible
because the material gets sticky in this zone and
exhibits higher friction than ABS which can make it
difficult to extrude and causes more extruder jams
[23].
2) ABS
Acrylonitrile Butadiene Styrene (ABS) is a
commonly used lightweight thermoplastic that can
be used for extruding and ejection moulding. It is
less brittle and requires less force to extrude than
PLA but handles higher temperatures better.
Therefor no active cooling is required and it does a
better job at printing small parts compared to PLA.
The downside of ABS is that it has more shrinking
problems and has to be extruded at a higher
temperature: It has a glass transition temperature of
around 105 °C. Because ABS is amorphous it has no
true melting point, however 230°C is the standard
for printing [24].
3) Colorfabb XT
ColorFabb XT, a material manufactured by
Colorfabb, is the first 3D printer filament produced
from Amphora 3D Polymer, a PETG variant. It’s a
strong and tough material that handles high
temperatures well, has less shrinking problems and
does a better job at bridging than ABS. ColorFabb
XT is best printed at 240-260°C and a HBP
temperature of 75°C [25].
4) Esun Conductive filament
The first Carbomorph variant we could get our
hands on was Esun’s Conductive Filament. Esun is a
Shenzhen based 3D printing filament supplier and
one of the few suppliers of conductive filament
when we started this research. It sells the conductive
B.
filament in a 1.75 and 3 mm variants. Our first tests
were done with the 1.75 mm variant and later on we
also tested the 3 mm variant. The datasheet doesn’t
really specify its composition but claims the material
has a surface resistance of 800 Ω and a print
temperature of 220-260°C [26].
Proto-Pasta conductive PLA
Proto-Pasta Conductive PLA, manufactured by a
company called Protoplant, is a compound of
Natureworks 4043D PLA, a dispersant and
conductive carbon black. It has the same features as
regular PLA but is a bit more flexible and can be
printed at the same temperatures [27].
6) Bare Conductive Electric Paint
An east London based company called Bare
Conductive sells a product called ‘Electric Paint’.
Essentially it’s a mixture of paint and carbon,
making it electrically conductive. According to the
company the paint can act as a "paintable wire" that
can be used on paper, cement, textiles, wood and
other materials, and becomes conductive once it
dries.
7) Bronzefil
Colorfabb Copperfill is a filament produced with
a micronized copper powder, which has been
infused into a common PLA plastic. We did some
tests with printing Copperfill put unfortunately the
material is not conductive.
5)
As a comparison we measured the resistance on
all conductive materials we used.
TABLE I.
OVERVIEW TESTED CONDUCTIVE PRINTING MATERIALS
Properties
Material
Technique
Resistance
100 mm
filament
ProtoPasta
FFF
987 Ω
Esun 3mm
FFF
172 kΩ
Esun 1.75 mm
FFF
123 kΩ
Bare
Conductive
Ink
167 kΩa
Bronzefill
FFF
∞
a.
Remarks
Easy to print
Lower resistance
Difficult to print
High resistance
Difficult to print
High resistance
Cumbersome process
High resistance
Material is not
conductive
nozzles is not precise enough resulting in a lot of
prints being scratched or pulled loose because of
height difference between the nozzles. Because we
installed two different diameter sizes of nozzles in
our system, something we have never seen on any
other printer, we suspect the slicing software
confused the feed rates of the different nozzles
resulting in a lot of tests with signs of over and
under extrusion (Fig. 17). We also had a lot of
oozing issues. We tried to solve this within the
slicing software. A few options we tried were
extensive retraction distances on a tool change, this
helped a little but didn’t completely solve the
problem. In Slic3r, a slicing program we used, there
is an option to cool down the inactive nozzle after a
tool change and before the active nozzle starts
extruding, this solved the problems of oozing but
brought some new problems with it: a print takes
about five times as long to print and the nozzles
were clogged all the time, especially when using the
conductive material. With the Cura slicing engine an
ooze shield can be added. This is a thin shell that is
automatically printed around the object shielding it
from oozing nozzles. At the moment of testing the
dual extrusion system on the UMO the Esun
conductive filament was the only conductive
filament we could get our hands on. After some
basic tests this material appeared to be really
difficult to print with. The material doesn’t like to
stick to the HBP or to other materials, it has severe
oozing problems and leaves a lot of residual material
in the print head, which causes a lot of print head
jams and was also a big problem when we used the
temperature switch technique in the Slic3r software.
When printing the material together with other
materials a lot of warping occurred. After weeks of
tweaking and tuning both hardware and software
without any significant progress we abandoned this
path and decided to look for a different solution.
A 100 mm long 3mm diameter channel filled with Bare Conductive Electric Paint
III.
RESULTS
Dual extrusion on the UMO
We encountered a lot of problems while trying to
print the dual extrusion system we installed on the
UMO. Our system to control the height of the
A.
Fig. 17. A printed traffic cone showing obvious signs of over extrusion.
Fig. 18. Severe oozing problems
Fig. 19. Dual extrusion attempts on the UMO
Dual extrusion on the Prusa I3
When we came across the Dondolo dual
extrusion system on Thingiverse we immediately
noticed that a few of the major problems we were
having with our own dual extrusion design were
cleverly solved in this design. Because the inactive
nozzle pivots up on a tool change it sits a few
millimeters higher than the active nozzle so it can’t
scratch the printed part or pull it loose. While the
inactive nozzle is pivoted away it rests on a
designated ‘ooze plate’ acting as a shield so no
material can drip out of the nozzle when inactive.
B.
Fig. 20. Schematic overview of the Dondolo dual extrusion system
After installing the Dondolo Dual Extrusion
system on the Prusa I3 we immediately received a
lot better results than our attempts with the UMO.
We started off by printing calibration prints in PLA.
A problem that occurred was that the material that
rested inside of the inactive nozzle would heat up
and become very liquid, leaving a drip mark on
certain prints after a tool change. We solved this by
adding a retraction before a tool change in the slicer
software. Another problem we had was that the left
idler didn’t give enough clearance space when the
left nozzle was inactive causing the filament to be
pulled up while the right extruder was extruding.
After measuring and testing we discovered this was
caused by a deformed part that limited the
movement of the left idler. We redesigned the
rocking clamp which provided the idler with some
more clearance space when inactive and decided to
redesign the idlers themselves enhancing the spring
attachment points which allowed for more spring
tension. The next problem we were confronted with
was that when printing with the dual extrusion
system whenever a tool change occurred, meaning
that the printer switches from one extruder to the
other, it took some time (or length) before the active
nozzle printed consistently. We solved this by using
the Cura slice engine in Repetier Host, which gave
us the option to include a ‘wipe and prime tower’
(Fig. 21) in the prints. Before each printed layer the
nozzle is sent to extrude a square outside of the
printed object until the nozzle prints the material
consistently. After the square is drawn the nozzle
makes a small rapid movement over the square to
wipe the nozzle clean. When all the squares are
printed on top of each other this results in a tower
hence the name ‘wipe and prime tower’.
Fig. 21. Printing with wipe and prime tower
Dual extrusion with conductive materials
1) Controller with Makey Makey
On the Dondolo dual extrusion system we printed
a circular controller with four buttons (Fig. 22). For
the enclosure we used ABS and for the buttons we
used Esun conductive filament. For testing purposes
we hooked it up to a Makey Makey, a prototyping
board that you can hook up to anything that is
conductive and use it to control certain keys on a
computer [28].
C.
possibility of printing any shape you like with a 3D
printer the touch pads or touch surfaces can be used
in any shape. In our example the object becomes the
touch pad. We used our ‘capacitive touch sphere’ to
control integrated LED lights using an MPR121
Capacitive Touch Sensor Breakout Board and an
Arduino.
Fig. 24. 3D printed capacitive touch sphere
DISCUSSION, CONCLUSION AND FUTURE
WORK
In this paper we looked at two different
techniques to print conductive and non-conductive
materials simultaneously. Although not fully
optimized the second technique showed significantly
better results. We spend a lot more time on getting
the dual extrusion technique working than we
initially planned at the beginning of this research. It
proved to be the biggest challenge we had to face.
The first conductive filament we tried was very
difficult to print with and had a fairly high resistance
making it not useable for printing electrical circuits
yet. The second material we tried was already a big
improvement and a step in the right direction. While
the conductive materials we tested can already be
used for applications that require very little current
or for sensors we think that with further
development of the conductive printing materials
and optimized dual extrusion systems the
opportunities of printing circuit structures with FFF
machines will evolve rapidly. The results of this
research already shed a light on what the future of
printing with conductive material might offer. In a
next phase research could be done to optimize the
formula of conductive materials so they have less
resistance and can be used for printing fully
functional circuits.
IV.
Fig. 22. Our printed controller hooked up to a Makey Makey
2D Capacitive Wheelpad
We printed a capacitive wheel pad similar to the
wheel that’s used in the first generation of Apple’s
Ipods [29]. To control it we used an MPR121
Capacitive Touch Sensor Breakout Board and an
Arduino. This wheel pad could be used to control
music, light, video games and much more.
2)
Fig. 23. Printed capacitive touch wheel pad aside an existing capacitive touch
wheel pad
3)
3D Capacitive Touch Sphere
We printed half of a sphere with integrated touch
surfaces. Most capacitive touch pads we see today
are limited to a two-dimensional plane. With the
ACKNOWLEDGMENT
This research paper is made possible through the
help and support from friends, family, teachers and
fellow students but I especially would like to
dedicate my acknowledgment of gratitude toward
the following significant advisors and contributors:
[9]
M. MOLITCH-HOU, “Voxel8: 1st Electronics 3D Printer - 3D
Printing Industry,” 2015. [Online]. Available:
http://3dprintingindustry.com/2015/01/05/voxel8-unleasheselectronics-3d-printer-ces-world/. [Accessed: 11-May-2015].
[10]
S. J. Leigh, R. J. Bradley, C. P. Purssell, D. R. Billson, and D. a.
Hutchins, “A Simple, Low-Cost Conductive Composite Material for
3D Printing of Electronic Sensors,” PLoS One, vol. 7, no. 11, p.
e49365, Nov. 2012.
First and foremost, I would like to thank my
supervisors from the University, Cesar Vandevelde
and Jelle Saldien for giving me the opportunity to
work on this project. Their valuable insights and
directions gave me needful guidance to complete the
research and write this paper.
[11]
M. Frauenfelder, “Make: Ultimate Guide to 3D Printing 2014,”
Make: Magazine, 2012.
[12]
“Ultimaker Original | Ultimaker.” [Online]. Available:
https://ultimaker.com/en/products/ultimaker-original. [Accessed:
14-May-2015].
[13]
“Heated Bed - RepRapWiki.” [Online]. Available:
http://reprap.org/wiki/Heated_Bed. [Accessed: 14-May-2015].
[14]
“ABS or PLA? Choosing The Right Filament | Make:” [Online].
Available: http://makezine.com/2014/11/11/abs-or-pla-choosingthe-right-filament/. [Accessed: 14-May-2015].
Second, I would like to thank Maarten
Vanhoucke, researcher at the Industrial Design
Center in Kortrijk to share his knowledge and the
best available information about 3D printing and
electronics.
[15]
Last but not least I want to thank Gianni Franci
for sharing the design files of his dual extruder
system and to guide me through the process of
installing and modifying it.
R. Jones, P. Haufe, E. Sells, P. Iravani, V. Olliver, C. Palmer, and
A. Bowyer, “RepRap – The Replicating Rapid Prototyper,” 2009.
[16]
“Company update | Ultimaker.” [Online]. Available:
https://ultimaker.com/en/community/view/10344-companyupdate#entry90597. [Accessed: 23-May-2015].
REFERENCES
[17]
“Erik’s Bowden Extruder - RepRapWiki.” [Online]. Available:
http://reprap.org/wiki/Erik%27s_Bowden_Extruder. [Accessed: 21May-2015].
[18]
“v5 HotEnd Full Kit - 3mm Direct.” [Online]. Available: http://e3donline.com/E3D-V5-3mm-Direct-All-Metal-HotEnd?search=v5.
[Accessed: 15-May-2015].
[19]
“Prusa i3 - RepRapWiki.” [Online]. Available:
http://reprap.org/wiki/Prusa_i3. [Accessed: 21-May-2015].
[1]
K. H. Church, H. Tsang, R. Rodriguez, P. Defembaugh, R. Rumpf,
and E. Paso, “Printed Circuit Structures , the Evolution of Printed
Circuit Boards,” in Ipc Apex Expo Conference.
[2]
H. Kopetz, Real-Time Systems. 2011.
[3]
“FDM Technology, About Fused Deposition Modeling | Stratasys.”
[Online]. Available: http://www.stratasys.com/3dprinters/technologies/fdm-technology. [Accessed: 20-May-2015].
[20]
[4]
“Fused filament fabrication - RepRapWiki.” [Online]. Available:
http://reprap.org/wiki/Fused_filament_fabrication. [Accessed: 17May-2015].
J. Moilanen and V. Tere, “Manufacturing in motion: first survey on
3D printing community,” 2012.
[21]
“Fused Deposition Modelling (FDM) | Materialise.” [Online].
Available: http://www.materialise.com/glossary/fused-depositionmodelling-fdm. [Accessed: 17-May-2015].
“Dimension 1200es 3D Modeling Printers| Stratasys.” [Online].
Available: http://www.stratasys.com/3d-printers/designseries/dimension-1200es. [Accessed: 27-May-2015].
[22]
“What is Corn PLA plastic? | ecokloud.” [Online]. Available:
http://www.ecokloud.com/what-is-PLA.html. [Accessed: 27-May2015].
[23]
“PLA - RepRapWiki.” [Online]. Available:
http://reprap.org/wiki/PLA. [Accessed: 25-May-2015].
[24]
“ABS - RepRapWiki.” [Online]. Available:
http://reprap.org/wiki/ABS. [Accessed: 25-May-2015].
[25]
“ColorFabb - XT Co-Polyester Filaments produced from
AmphoraTM 3D Polymer by Eastman Chemical Company.”
[Online]. Available: http://colorfabb.com/xt-copolyester. [Accessed:
25-May-2015].
[5]
[6]
J. H. Lee, “Research: Ceramic/polymer Composite Materials
through Stereolithography,” 2001.
[7]
S. Castillo, D. Muse, F. Medina, E. Macdonald, and R. Wicker,
“Electronics Integration in Conformal Substrates Fabricated with
Additive Layered Manufacturing,” pp. 730–737.
[8]
“Voxel8 Unveils New Electronics 3D Printer At 2015 CES 3DPrint.com.” [Online]. Available:
http://3dprint.com/35085/voxel8-electronics-3d-printer/. [Accessed:
12-May-2015].
[26]
[27]
“ESUN 3D FILAMENT CONDUCTIVE BLACK ESUN.”
[Online]. Available:
http://www.esun3d.net/cpxx.aspx?id=171&TypeId=15. [Accessed:
12-May-2015].
“Conductive PLA – ProtoPlant, Makers of Proto-pasta.” [Online].
Available: http://www.proto-pasta.com/pages/conductive-pla.
[Accessed: 12-May-2015].
[28]
“Makey Makey | Buy Direct (Official Site).” [Online]. Available:
http://makeymakey.com/. [Accessed: 28-May-2015].
[29]
“Apple - Products - iPod History.” [Online]. Available:
https://www.apple.com/pr/products/ipodhistory/. [Accessed: 30May-2015].
Table of contents
1.! Introduction............................................................................................. 1!
1.1.! 3D printing ............................................................................................................ 1!
1.1.1.! Fused Filament Fabrication (FFF) ................................................................ 2!
1.1.2.! Stereo Lithography (SLA) .............................................................................. 3!
1.1.3.! Printing Materials .......................................................................................... 4!
1.2.! Electronics ............................................................................................................ 5!
1.2.1.! Current Electronics ........................................................................................ 5!
1.2.2.! Printed Circuit Structure (PCS) ..................................................................... 6!
2.! Market research...................................................................................... 7!
2.1.! Conductive material printing techniques ........................................................... 7!
2.1.1.! SLA with Manual Ink Dispensing .................................................................. 7!
2.1.2.! FFF with Automated Ink Dispensing ............................................................ 8!
2.1.3.! FFF with Conductive Filament ...................................................................... 9!
2.2.! Conductive material........................................................................................... 10!
2.2.1.! Bare Conductive Electric Paint ................................................................... 10!
2.2.2.! Esun Conductive Filament .......................................................................... 13!
2.2.3.! ProtoPlant Proto-Pasta Conductive PLA ................................................... 15!
2.2.4.! Colorfabb Copperfill .................................................................................... 16!
3.! Printer Modifications ............................................................................ 18!
3.1.! Ultimaker Original (UMO) .................................................................................. 18!
3.1.1.! Heated Build Platform ................................................................................. 19!
1.1.1.! LED Lighting ................................................................................................. 21!
3.1.2.! Dual extrusion system ................................................................................. 21!
3.2.! Prusa I3 .............................................................................................................. 32!
3.2.1.! Dondolo Dual Extruder ................................................................................ 33!
4.! Dual Extrusion ....................................................................................... 36!
4.1.! Preparing the Printer.......................................................................................... 36!
4.1.1.! Cleaning the Nozzle..................................................................................... 36!
4.1.2.! Seasoning the Hot-End................................................................................ 37!
4.1.3.! Calibrating the Printer ................................................................................. 38!
4.2.! Dual Extrusion with the UMO ............................................................................ 40!
4.3.! Dual Extrusion with the Prusa I3 ....................................................................... 44!
4.4.! Dual Extrusion Guide ......................................................................................... 50!
5.! Printing with Conductive Material ....................................................... 63!
5.1.! Esun conductive filament .................................................................................. 63!
5.1.1.! Controller with Makey Makey ..................................................................... 63!
5.2.! Proto-Pasta Conductive PLA............................................................................. 64!
5.2.1.! Capacitive Touch Wheel ............................................................................. 64!
5.2.2.! Capacitive Touch Sphere ............................................................................ 66!
6.! Conclusion ............................................................................................ 67!
7.! References ............................................................................................ 68!
8.! Appendixes ........................................................................................... 70!
Table of figures and tables
Fig. 1! Left: High-end 3D printer Stratasys Dimension [1] Right: Low-end 3D printer Ultimaker 2 [2] 1!
Fig. 2! Left: Schematic overview of the Fused Deposition Modeling process [4] right: filament used
for FFF machines [6]
2!
Fig. 3! Left: Schematic overview of the Stereolythography process [7] Right: Resin used for SLA [8] 3!
Fig. 4! Comparison of the same part printed with FFF (left) and SLA (right) [9]
3!
Fig. 5! A PCB mounted in an X-box controller [14]
5!
Fig. 6! A graphic rendition of future PCS [15]
6!
Fig. 7! Accelerometer System Helmet Insert [16]
7!
Fig. 8! Voxel8 Development Kit [17]
8!
Fig. 9! 3D Printed Interface Design [18]
9!
Fig. 10! First test setup with a single channel
10!
Fig. 11! Bare conductive paint (left) and CAD file of the test setup (right)
11!
Fig. 12! Measuring resistance on test setup
11!
Fig. 13! Table showing resistance measurements on second test setup
12!
Fig. 14! Esun conductive filament [20]
13!
Fig. 15! Test of Esun Conductive and PLA
14!
Fig. 16! Test of Esun Conductive and ColorFabb XT (warping)
14!
Fig. 17! Test cube in Proto-Paste Conductive PLA for measuring resistance
15!
Fig. 18! Protopasta Conductive PLA printing together with clear PLA
16!
Fig. 19! Protopasta Conductive PLA printed together with Colorfabb XT
16!
Fig. 20! Tests with different materials (from left to right) white PLA, Copperfill, XT and Glowfill
17!
Fig. 21! Comparison table for different conductive materials
17!
Fig. 22! Ultimaker original [24]
18!
Fig. 23! A warped print [25]
19!
Fig. 24! 3DPHK HBP installed on the UMO
20!
Fig. 25! Bottom of the UMO with the power supply and rising feet in place (left) and new IEC
connector and power switch added (right)
20!
Fig. 26! LED light strips installed on the UMO( left) and new 24V 16.7A 400W power supply (right) 21!
Fig. 27! Printed support structure on Stratasys Dimension printer [27]
22!
Fig. 28! M3 threaded inserts
23!
Fig. 29! Ultimaker 2 Print Head [2]
23!
Fig. 30! Cad file of prototype 1
24!
Fig. 31! A picture of prototype 1
24!
Fig. 32! Cad file of prototype 2
25!
Fig. 33! XY-carriage of prototype 2
25!
Fig. 34! Prototype 2 mounted on the UMO
26!
Fig. 35! Rendered exploded view of prototype 1
26!
Fig. 36! Flat pattern of the heat shield
27!
Fig. 37! Heat shield in 0,5 mm bent aluminium
27!
Fig. 38! Backside of our second prototype
28!
Fig. 39! Airtripper’s Bowden Extruder V3
29!
Fig. 40! Left: oozing problem while printing with the dual extruder system on the UMO, right: the print
getting pulled loose by the inactive nozzle
31!
Fig. 41! Prusa I3 Metal Frame [30]
32!
Fig. 42! CAD drawing of the Dondolo dual extrusion system by Gianni Franci [31]
33!
Fig. 43! Schematic overview of the Dondolo Dual Extruder
34!
Fig. 44! Left: Self-made drive gear right: UM2 drive gear
35!
Fig. 45! Comparison teeth marks from selfmade drive gear (left) and UM2 drive gear (right)
35!
Fig. 46! A piece of nylon filament we used to clean a dirty nozzle (black is Esun conductive)
36!
Fig. 47! PLA jam problem solved after seasoning the hot end
37!
Fig. 48! Flowchart for calibrating steps/mm
38!
Fig. 49! Flowchart for fine-tuning steps/mm
39!
Fig. 50! A part used for fine tuning steps/mm
39!
Fig. 51! A number of test-cubes used for calibration on the UMO
41!
Fig. 52! Calibration prints on the UMO
41!
Fig. 53! Over extrusion on the UMO
42!
Fig. 54! Over extruded traffic cone printed on the UMO
42!
Fig. 55! Oozing problem of Esun Conductive Filament
43!
Fig. 56! The Dondolo Dual Extruder installed and running on the Prusa I3
45!
Fig. 57! Side view of the installed Dondolo Dual Extrusion System
45!
Fig. 58! A view of the cable chain and the PCB cooling fan
46!
Fig. 59! Dual Extrusion Calibration test when not calibrated properly
46!
Fig. 60! Several calibration tests for trying to get the XY allignment just right
47!
Fig. 61! Dual Extrusion Calibration in PLA(left) and ABS (right) when properly calibrated
47!
Fig. 62! A drip mark on a PLA print (left) and a calibration print (right)
47!
Fig. 63! Difference in clearance between right and left idler
48!
Fig. 64! The redesigned dondolo extruder
48!
Fig. 65! Prusa I3 printing a traffic cone with a wipe and prime tower and an ooze shield
49!
Fig. 66! First model the part in Solidworks you want in one type of material
50!
Fig. 67! Next model the part you want to print in the other material. Remember not to merge it with
the other object
50!
Fig. 68! This is your part with different solid bodies for each material
51!
Fig. 69! Right click on a solid body you want in a different material and select delete/keep bodies 51!
Fig. 70! Select all bodies you want to delete and click OK
52!
Fig. 71! Now you are left with the pieces in one material
52!
Fig. 72! Save this part as an STL
53!
Fig. 73! In the delete body feature select the pieces in the other material
53!
Fig. 74! Now you are left with the piece in the other material
54!
Fig. 75! Save the other part as an STL giving it a different name
54!
Fig. 76! Open Repetier Host and adjust the printer settings. The X and Y offset can be found using a
calibration piece
55!
Fig. 77! Click the + button to add the STL files
56!
Fig. 78! Select both STL files and click ‘open’
56!
Fig. 79! With the STL files imported click on the settings button of the first object
57!
Fig. 80! Adjust the assigned extruder and set both objects in the same object group to merge them
57!
Fig. 81! Press the rotate button to oriëntate the object correctly
58!
Fig. 82! Oriëntate the object and double check the assigned extruders
58!
Fig. 83! In the slicer tab select the slicer engine you want to use. We like CuraEngine. Click on
configuration
59!
Fig. 84! Adjust the settings accordingly. These are the settings that gave us the best results.
60!
Fig. 85! In the filament tab make an entry for each different filament you are using
60!
Fig. 86! Adjust the settings in the slicer tab and click ‘Slice with CuraEngine’
61!
Fig. 87! Connect the printer and press print or save the Gcode file to an SD card
62!
Fig. 89! The combined STL file of the controller
63!
Fig. 90! Controller in ABS and Esun Conductive Filament
63!
Fig. 91! Proto-Pasta and clear PLA printing on the Prusa I3
64!
Fig. 92! The STL file of the buttons
64!
Fig. 93! The prusa I3 prining the capacitive touch wheel
65!
Fig. 94! Testing the capacitie touch wheel
65!
Fig. 95! Combined STL file of the capacitive sphere
66!
Fig. 96! Picture of the capacitive sphere controlling LED’s
66!
List of abbreviations and symbols
3D
Three-dimensional
ABS
Acrylonitrile Butadiene Styrene
AM
Additive Manufacturing
FFF
Fused Filament Fabrication
HBP
Heated Build Plate
PCB
Printed Circuit Board
PCS
Printed Circuit Structure
PLA
Polylactic Acid
SLA
Stereo Lithography
SMT Surface-Mount Technology
SMD Surface-Mount Device
STL
Surface Tessellation Language
UM2 Ultimaker 2
UMO Ultimaker Original
1. Introduction
1.1. 3D printing
3D Printing or Additive Manufacturing (AM) is a rapid prototyping technique that lets
users physically create three-dimensional (3D) objects drawn with a computer. The
object is usually modelled with a computer aided design (CAD) software package
and exported as a Surface Tessellation Language (STL) file. Slicing software slices
the part in two-dimensional layers, which are sequentially printed on top of each
other to create a solid object. As opposed to subtractive manufacturing (SM), a
technique that takes a raw metal and creates a part by cutting or drilling sections
away, additive manufacturing is less expensive, less time consuming and produces
much less waste material.
There are a few different techniques for 3D printing. Because this research focuses
on 3D printing on low-end machines we are going to describe the two techniques
that are most used in these cheaper machines: Fused Filament Fabrication (FFF) and
Stereo Lithography (SLA).
Fig. 1
Left: High-end 3D printer Stratasys Dimension [1] Right: Low-end 3D printer Ultimaker 2 [2]
1
1.1.1. Fused Filament Fabrication (FFF)
FFF is equivalent to Fused Deposition Modelling (FDM), a term and abbreviation that
is trademarked by Stratasys Inc [3]. The term fused filament fabrication (FFF), was
invented by the members of the RepRap project to provide a term that would be
legally independent in its use [4]. An FFF 3D printer extrudes a thermoplastic filament
through a temperature-controlled nozzle similar to how a hot glue gun extrudes a
melted glue-cartridge (Fig. 2). The nozzle heats the material to a semi liquid state
and draws the outline in ultra thin layers (typically between 0.05 mm to 0.3 mm) onto
a build platform. It then fills the outline with a raster of material creating a complete
section of the object and proceeds to the next layer, binding it to the previous one.
The result is a plastic 3D model built up one layer at a time. Because sometimes not
all the layers are touching the build platform a support structure can be created
which can be removed after the print is finished. Because the printed parts are
relatively strong and durable this technique is ideal for functional prototypes and the
quick testing of shapes and fittings [5].
Fig. 2
Left: Schematic overview of the Fused Deposition Modeling process [4] right: filament used
for FFF machines [6]
2
1.1.2. Stereo Lithography (SLA)
Stereo Lithography (SLA) uses a laser beam to harden the surface of vessel of liquid
resin to create a part (Fig. 3). Where the laser beam hits the liquid, the hardening
takes effect. When a layer is finished, the platform that holds the object drops a
fraction of a millimetre deeper into the vessel. The different layers that solidify on
top of each other form the 3D object. Similar to FFF sometimes support structures
are required for overhangs and holes, these can be added either manually or
automatically in the slicing software. After the product is removed from the build
platform the support structure can be removed. SLA has a higher print resolution,
builds quicker and can print more complex structures but the machines and the resin
are much more expensive than using FFF.
Fig. 3
Left: Schematic overview of the Stereolythography process [7] Right: Resin used for SLA [8]
Fig. 4
Comparison of the same part printed with FFF (left) and SLA (right) [9]
3
1.1.3. Printing Materials
A)
PLA
Polylactic acid (PLA) is a biodegradable polymer that is made from lactic acid, a
natural substance gained from corn crops making it ideal for usage in the poorer
counties of the world and a non-toxic and renewable resource. PLA biodegrades in
approximately 60 days while other plastics can take up to 400 years to degrade [10].
The material is harder than ABS and has significantly less shrinking problems. It
melts at a relatively low temperature (around 180°C to 220°C), and has a glass
transition temperature between 60-65 °C, making it a very useful material. When
printing PLA it is important to keep the distance between the glass temperature point
and the melting point as small as possible because the material gets sticky in this
zone and exhibits higher friction than ABS which can make it difficult to extrude and
causes more extruder jams [11].
B)
ABS
Acrylonitrile Butadiene Styrene (ABS) is a commonly used lightweight thermoplastic
that can be used for extruding and ejection moulding. It is less brittle and requires
less force to extrude than PLA but handles higher temperatures better. Therefor no
active cooling is required and it does a better job at printing small parts compared to
PLA. The downside of ABS is that it has more shrinking problems and has to be
extruded at a higher temperature: It has a glass transition temperature of around
105 °C. Because ABS is amorphous it has no true melting point, however 230°C is
the standard for printing [12].
C)
Colorfabb XT
ColorFabb XT, a material manufactured by Colorfabb, is the first 3D printer filament
produced from Amphora 3D Polymer, a PETG variant. It’s a strong and tough
material that handles high temperatures well and has less shrinking problems and
does a better job at bridging better than ABS. ColorFabb XT is best printed at 240260°C and a HBP temperature of 75°C [13].
4
1.2. Electronics
1.2.1. Current Electronics
Today most electronic devices consist of some type of enclosure with one or more
printed circuit boards (PCBs) mounted inside (Fig. 5). Onto these PCBs the
necessary components to make the device functional are mounted using surfacemount technology (SMT) or through hole soldering. The shape and size of the
enclosure depends heavily on the shape and size of the PCB and its components.
This limits the designer in shaping the device because he has to bear in mind the
space needed to fit the PCB.
Fig. 5
A PCB mounted in an X-box controller [14]
5
1.2.2. Printed Circuit Structure (PCS)
With a big increase in popularity over the past few decades additive manufacturing
or 3D printing could change the way we build electronic devices in the future. Instead
of using PCBs that are mounted afterwards in the device Printed Circuit Structure
(PCS) would look at electronics from a completely different angle. In a PCS the
enclosure and structure of the device itself would carry the circuits and components
making the usage of PCBs unnecessary. In this approach components can be
smoothly integrated and even hidden inside the structure. This also makes reverse
engineering much more difficult. By building the electronics into the structure the
device would become more rigid, eliminating the use of glue, snaps, solder, wiring or
bolts. This would also result in the ability to use much more components in far less
space, making it possible to create smaller and less bulky devices while not
sacrificing in its functionality. It would also open up new possibilities by making it
possible to print functional components and sensors like 3D touch surfaces,
integrated bend or turn sensors, optimized antennas, custom motors, speakers,
solenoids and much more [15].
Fig. 6
A graphic rendition of future PCS [15]
6
2. Market research
2.1. Conductive material printing techniques
Although PCSs are still at a very early stage numerous researchers have attempted
to fabricate 3D and conformal electronics using different types of 3D printing
techniques. This section gives an overview of the techniques already used.
2.1.1. SLA with Manual Ink Dispensing
An SLA machine is used to print the structure and afterwards the components are
placed and the traces are filled with conductive silver ink. This technique was used
by S. Castillo et al to create a three-dimensional accelerometer sensor system with
microprocessor control [16].
Fig. 7
Accelerometer System Helmet Insert [16]
7
2.1.2. FFF with Automated Ink Dispensing
This technique features a machine that has two types of material dispensing
systems. A nozzle that uses the FFF technique to build the structure and an
automatic ink dispenser that provides the traces of the circuit. None such a machine
is available on the market but at this moment a company called Voxel8 is in the final
stages of developing such a machine [17].
Fig. 8
Voxel8 Development Kit [17]
8
2.1.3. FFF with Conductive Filament
This technique uses a standard FFF 3D printer to print with a new type of material
called ‘Carbomorph’. Carbomorph, a mixture of conductive Carbon Black (CB) and
polymorph, was invented by S. J. Leigh et al and used to make a flex sensor, 2D
capacitive touch buttons and a smart vessel which tracks the liquid inside [18].
Fig. 9
3D Printed Interface Design [18]
Because the focus of our research was to explore a technique that can be used on
low-end 3D printers we decided to mainly focus on the last technique.
9
2.2. Conductive material
While looking for conductive material to print with we noticed that because this
technique is so new the market supply is limited. We mainly wanted to focus on
printing with FFF but also explored some other approaches as well.
2.2.1. Bare Conductive Electric Paint
An east London based company called Bare Conductive sells a product called
‘Electric Paint’. Essentially it’s a mixture of paint and carbon, making it electrically
conductive. According to the company the paint can act as a "paintable wire" that
can be used on paper, cement, textiles, wood and other materials, and becomes
conductive once it dries [19]. To measure its resistance we printed a test setup with
channels in different diameters. First we printed a rectangular block with a channel
running from one side to the other. Using a syringe we filled the channel with the
paint and let it dry.
Fig. 10 First test setup with a single channel
For our next test we printed a rectangular block with different channels running
through it. The hollow channels were printed with different diameters ranging from 2
mm to 6 mm in steps of 0,5 mm. Then we mixed some conductive paint with water,
making the paint more liquid. We filled the channels with the thinned paint so the
paint was covering the sides of the channels and then pored the thinned paint out.
The result was a hollow channel with conductive sides. After drying the paint in the
oven we measured the resistance of the channels (Fig. 13). We can conclude there is
10
a lot of variation in the measurements so the usage of this technique is not ideal. It
was also a messy and cumbersome process.
Fig. 11 Bare conductive paint (left) and CAD file of the test setup (right)
Fig. 12 Measuring resistance on test setup
11
Following table shows the measurements we made using our second test setup:
Diameter (mm)
Resistance
2
59,7 k!
2,5
27 k!
3
34,2 k!
3,5
111,1 k!
4
49,4 k!
4,5
53.1 k!
5
31,6 k!
5,5
80 k!
6
29,4 k!
Fig. 13 Table showing resistance measurements on second test setup
12
2.2.2. Esun Conductive Filament
The first Carbomorph variant we could get our hands on was Esun’s Conductive
Filament. Esun is a Shenzhen based 3D printing filament supplier and one of the few
suppliers of conductive filament when we started this research. It sells the
conductive filament in a 1.75 and 3 mm variants. Our first tests were done with the
1.75 mm variant and later on we also tested the 3 mm variant. The datasheet
(Appendix 1) doesn’t really specify its composition but claims the material has a
surface resistance of 800 ! and a print temperature of 220-260°C. When testing this
material on our printer we noticed it was very difficult to print with it. The problems
we were having were:
•
The material doesn’t bind to the HBP or to other materials (Fig. 15)
•
The material has severe oozing problems
•
The material leaves a lot of residual material in the print head which causes a
lot of print head jams
•
When using the material together with other materials a lot of warping
occurred (Fig. 16)
Fig. 14 Esun conductive filament [20]
13
Fig. 15 Test of Esun Conductive and PLA
Fig. 16 Test of Esun Conductive and ColorFabb XT (warping)
14
2.2.3. ProtoPlant Proto-Pasta Conductive PLA
Proto-pasta Conductive PLA, manufactured by a company called Protoplant, is a
compound of Natureworks 4043D PLA, a dispersant and conductive carbon black. It
has the same features as regular PLA but is a bit more flexible and can be printed at
the same temperatures [21].
We measured the conductivity by printing a 1cm cube on a Prusa I3 and soldering
wires on each side so could measure the resistance perpendicular to the layers and
through the layers:
•
Volume resistivity of 3D printed parts perpendicular to layers: 46 ohm-cm
•
Volume resistivity of 3D printed parts through layers (along Z axis): 84 ohmcm
Fig. 17 Test cube in Proto-Paste Conductive PLA for measuring resistance
Proto-Pasta prints very nicely together with regular PLA (Fig. 18). We also tried
printing it together with Colorfabb XT (Fig. 19) but the two materials wouldn’t bind
together.
15
Fig. 18 Protopasta Conductive PLA printing together with clear PLA
Fig. 19 Protopasta Conductive PLA printed together with Colorfabb XT
2.2.4. Colorfabb Copperfill
Colorfabb Copperfill is a filament produced with a micronized copper powder, which
has been infused into a common PLA plastic. We did some tests with printing
Copperfill put unfortunately the material is not conductive.
16
Fig. 20 Tests with different materials (from left to right) white PLA, Copperfill, XT and Glowfill
To compare the different materials we measured the resistance of 100mm filament.
For the conductive paint we printed a 3mm diameter, 100 mm long channel and filled
it with the paint for comparison.
Properties
Material
Technique
Resistance 100
mm filament
Remarks
ProtoPasta
FFF
987 !
Easy to print
Esun 3mm
FFF
172 k!
Difficult to print
Esun 1.75 mm
FFF
123 k!
Difficult to print
Bare Conductive
Ink
167 k!
Bronzefill
FFF
∞
a
Cumbersome
process
Material is not
conductive
Fig. 21 Comparison table for different conductive materials
17
3. Printer Modifications
The 3D printers that were used for this research are low-end FFF 3D printers. We
used 3 different types of printers: an Ultimaker Original (UMO), an Ultimaker 2 (UM2)
and a RepRap Prusa I3 [22]. The UM2 was mainly used to print parts for upgrading
the other two printers. This section will give an overview of the upgrades we made.
3.1. Ultimaker Original (UMO)
The UMO (Fig. 22) is the first model of a Dutch based company called Ultimaker BV.
It’s original name was Ultimaker but the company added the suffix ‘original’ when
they released their second model: the ‘Ultimaker 2’ The UMO is a Cartesian FFF 3D
printer that uses 3mm filament and can print a number of different materials. The
printer is also known to be a ‘hackable’ printer, since it mostly uses simple laser cut
or printed parts and open source software running on an Arduino Mega board. In
2012, the UMO was awarded ‘Fastest and Most Accurate 3D printer available’ in
MAKE Magazine's annual 3D printing guide [23]. For our research we did some
upgrades and alterations to the printer. We installed a heated build platform, LED
lights, shield windows and a dual extruder.
Fig. 22 Ultimaker original [24]
18
3.1.1. Heated Build Platform
A heated build platform (HBP) improves printing quality by helping to
prevent warping. When the printed plastic cools down, it has the tendency to shrink.
Because the sides of the object cool faster than the inside, mainly while printing in
ABS, sometimes warping occurs. Because of this warping the corners of the part
tend to come loose from the build platform (Fig. 23). When a HBP is installed the
printed part stays warm during the printing process allowing the shrinking to happen
more evenly. This results in a higher quality finish with materials such
as ABS and PLA. A HBP also allows users to print without rafts, skirts and brims. The
heated build platform we installed is a kit we obtained from a vendor on EBay.
Fig. 23 A warped print [25]
19
Fig. 24 3DPHK HBP installed on the UMO
The HBP features a 3 mm aluminium core PCB with an integrated PCB heater, LED
indicators and thermistors that allows for fast heating (20°C to 100°C in < 5 minutes).
The kit also provided a 24V 10A 240W DC power supply, which we installed to
provide power to both the printer and the HBP. To fit the power supply we provided
the printer with some raising feet so the supply could fit snugly in the bottom of the
printer next to its electronics. To reduce components we used the new power supply
to also provide power to the printer itself. We also replaced the 4-point levelling
system of the HBP with a much easier to use 3-point leveling system.
Fig. 25 Bottom of the UMO with the power supply and rising feet in place (left) and new IEC
connector and power switch added (right)
20
1.1.1.
LED Lighting
Sometimes it’s hard to see how the printer is because of bad light conditions. In
order to prevent this we provided the printer with LED light strips. We attached 3
white LED strips to the inside of the front panel of the printer, 12 LED’s at the sides
and 18 LED’s at the bottom. When attaching this to the power supply we noticed the
supply couldn’t handle this and the LED’s would start blinking when the heated build
platform was active. It appeared that the power supply include in the heated build
platform kit wasn’t powerful enough to power the build platform, the LED’s and the
heaters at once. Therefore we installed a more powerful 24V 16.7A 400W DC power
supply that could handle feeding all of the components without a problem.
Fig. 26 LED light strips installed on the UMO( left) and new 24V 16.7A 400W power supply (right)
3.1.2. Dual extrusion system
In order to be able to print two materials, being it conductive and non-conductive or
just two different colours or materials, simultaneously we added a dual extrusion
system to the UMO. This was not an easy task because the dual extrusion technique
itself is still pretty new and few companies have managed to make it work on these
low-cost machines. Professional 3D printers use the technique to generate support
structures but they have much more control because they use heated chambers and
all their printing materials come from the same manufacturer. Ultimaker sells an
‘experimental’ upgrade for the UMO and was planning to develop a dual extrusion
upgrade for the UM2 as well but in a company update released on their community
forum [26] they announced they cancelled the development of the upgrade due to
technical difficulties.
21
Fig. 27 Printed support structure on Stratasys Dimension printer [27]
The hot ends we used were E3D’s V5 all metal hot ends. Because some types of
filaments are only available in certain diameters we chose to use a combination of a
2.85 and a 1.75 mm hot ends which would allow us to also print with these two
different types of filament diameters.
Our first prototype was inspired by the print head used by the UM2 (Fig. 29), a printer
we obtained great results with. While the UM2 is sold with only one nozzle the print
head is also equipped to hold 2 nozzles. The design of the dual extruder consists of
a XY-carriage 3d printed in ABS. In this carriage both hot ends are mounted and can
be adjusted in height separately by loosening the front mounting bracket. On the
backside two 30x30x10 mm fans were mounted to cool the heat breaks, this is
necessary because there is a short transition zone between the glass transition
temperature and the melting temperature of the materials used. On the bottom of
the print head is a bended aluminium plate which acts as a heat break between the
hot end and the cooled part and on each side the plate was bend to act as a fan duct,
holding two 40x40x10 fans to actively cool the print area, this is particularly useful
when printing bridges or small details in PLA. For connecting the different parts
together we used M3 threaded inserts (Fig. 28).
22
Fig. 28 M3 threaded inserts
In our second prototype we opted to also print the fan ducts because it was too
complicated to bend the aluminium plate the way we wanted.
Fig. 29 Ultimaker 2 Print Head [2]
23
Fig. 30 Cad file of prototype 1
Fig. 31 A picture of prototype 1
24
Fig. 32 Cad file of prototype 2
Fig. 33 XY-carriage of prototype 2
25
Fig. 34 Prototype 2 mounted on the UMO
Fig. 35 Rendered exploded view of prototype 1
26
Fig. 36 Flat pattern of the heat shield
Fig. 37 Heat shield in 0,5 mm bent aluminium
27
Fig. 38 Backside of our second prototype
The two extruder motors were mounted on the back of the printer and connected to
the hot ends via ‘Bowden tubes’. Because the extruder motors are not attached to
the print head the moving mass of the head is reduced, hereby allowing the head to
make faster controlled motions. As a result the machine will shake less, use less
energy and print faster. The system has one major disadvantage: hysteresis. By
putting pressure on such a long length of filament a lot more compression occurs,
leading to a dynamic lag between the input and output of the tube. The flexibility of
the Bowden tube increases the problem. It’s possible to control this problem with
software calibration [28]. For the feeding of the 3mm filament head we used the
original feeding mechanism of the UMO and for the 1.75mm filament head we used
a design we found on Thingiverse called Airtripper’s Bowden Extruder V3 (Fig. 39)
uploaded by the user ‘Airtripper’ [29].
28
Fig. 39 Airtripper’s Bowden Extruder V3
Because we are using two different sizes of nozzles the extruder motors both need
to have their own feeding speed, the speed the extruder motor is set to in order to
push the material through the nozzle. Unfortunately this was not possible with Marlin,
the standard firmware of the UMO. Here for we opted for installing ‘Repetier
Firmware’, another firmware solution that made it possible to assign different feed
rates to each extruder. By installing the new firmware some other problems
appeared; the display stopped working and the pins had to be re-assigned in the
firmware, it was not possible to slice with ‘Cura’, Ultimaker’s standard slicing
software, anymore because the program wouldn’t recognize the different feed rates.
The solution for this was using ‘Repetier Host’ a slicing program made by the same
developers of the new firmware we installed.
These are the changes that needed to be made in the UIconfig.h file of Repetier
Firmware in order to make the UMO display work (also see Appendix 4-7):
29
#define UI_DISPLAY_TYPE 1
#else // Direct display connections
#define UI_DISPLAY_RS_PIN
20
#define UI_DISPLAY_RW_PIN
-1
#define UI_DISPLAY_ENABLE_PIN
17
#define UI_DISPLAY_D0_PIN
59
#define UI_DISPLAY_D1_PIN
64
#define UI_DISPLAY_D2_PIN
44
#define UI_DISPLAY_D3_PIN
66
#define UI_DISPLAY_D4_PIN
16
#define UI_DISPLAY_D5_PIN
21
#define UI_DISPLAY_D6_PIN
5
#define UI_DISPLAY_D7_PIN
6
#define UI_DELAYPERCHAR
320
30
With the hardware installed and all software and firmware problems solved some
new problems occurred, it appeared to be very difficult to install both nozzles at
exactly the same height and aligning the HBP accordingly. Also, when printing, a lot
of ‘oozing’ occurred, when one hot end is inactive it stays hot resulting in material
dripping out of the nozzle and cluttering the print (Fig. 40). Additionally, because
both nozzles were at the same height, the inactive nozzle would scratch the print
while printing or even pulling it loose from the HBP. After weeks of frustration trying
to solve the problems by tweaking the software and hardware we abandoned this
path and decided to look for a different solution.
Fig. 40 Left: oozing problem while printing with the dual extruder system on the UMO, right: the
print getting pulled loose by the inactive nozzle
31
3.2. Prusa I3
The Prusa I3 (Fig. 41) is the third iteration of the Prusa mendel, which was developed
as part of the RepRap [22] project. This project started the 3D printer revolution by
building low-cost, self-replicating, open-source 3d printers. It has become the most
widely used 3D printer among the global members of the Maker Community. The
frame of our model was made of a single sheet of aluminium and uses a RAMPS 1.4
controller. It’s also a Cartesian printer and the main difference between this printer
and the UMO is that this printer moves the build platform for the Y-movement where
as the UMO moves the print head itself. This printer also doesn’t feature an enclosed
frame making it less ideal to print ABS. We upgraded this printer with a dual
extrusion system.
Fig. 41 Prusa I3 Metal Frame [30]
32
3.2.1. Dondolo Dual Extruder
While looking for other dual extrusion systems after our failed attempt on the UMO
we came across a design shared on Thingiverse called ‘Dondolo V1.0b’ [31]. It was
uploaded by user Gianni Franci and made specifically for the Prusa I3. It looked
promising, using a similar technique as seen in the more expensive Stratasys
Dimension printers, allowing the hot ends to pivot around an axis. This not only
solves the problem of the nozzle scraping the print but also reduces oozing due to
the inactive nozzle being blocked by an ‘anti-oozing’ plate. The design uses an RC
servo to make the hot ends pivot around the axis. The axis used as a pivot point is
the axis of the single stepper motor driving the extrusion for both hot ends. The
design was originally made for E3D’s V6 all metal hot ends but after some minor
modifications we were able to make it work for the V5 hot ends as well. To reduce
complexity in firmware settings we decided to use two hot ends for the same
filament diameter; 2,85 mm. For the extruder motor a stepper with high phase
resistance and inductance was needed while still remaining a high torque. The
NEMA17 42BYGHW208 (Appendix 2) stepper motor met these requirements.
Fig. 42 CAD drawing of the Dondolo dual extrusion system by Gianni Franci [31]
33
Fig. 43 Schematic overview of the Dondolo Dual Extruder
For driving the filament through the extruder we needed a drive gear with sharp teeth.
We made one ourselves (Fig. 44) from an 8mm rod that we machined. The teeth we
carved using an M5 thread tap on a milling machine. Later on we noticed this gear
was not driving the filament consistently so we used the gear from the UM2, which
also has sharp teeth and extruded more consistently (Fig. 45).
34
Fig. 44 Left: Self-made drive gear right: UM2 drive gear
Fig. 45 Comparison teeth marks from selfmade drive gear (left) and UM2 drive gear (right)
35
4. Dual Extrusion
Before we could begin printing with conductive materials it was important the dual
extrusion system worked properly. As mentioned before printing with a dual extruder
setup is easier said than done. Because you now have two extruders, which have to
be at precisely the same distance from the build platform, levelling the build platform
is a bit more complicated. If one extruder head is too high it will not properly attach
the extruded material to the build platform or to the previous layers. Two extruders
also mean double the chance of a nozzle being clogged. When printing a part with
two different materials both nozzles have to work perfectly or the print will be ruined.
4.1. Preparing the Printer
4.1.1. Cleaning the Nozzle
We found a good way to clean out dirty nozzles along the way. Nylon filament
worked particularly well for this job. We heat the nozzle to 240°C. Feed some nylon
filament through the nozzle. Let the nozzle cool down to 130°C and gently pull out
the nylon filament. When you do this right you can see the shape of the nozzle and a
very thin piece of wire that was in the top end (Fig. 46). Repeat this process until all
the other material is gone and you just pull out clean nylon.
Fig. 46 A piece of nylon filament we used to clean a dirty nozzle (black is Esun conductive)
36
4.1.2. Seasoning the Hot-End
For some reason our printer (UMO with E3D all metal hot end V5) had problems with
printing PLA. This problem also occurred before installing the heated bed so this
couldn’t be the cause of the problem. We went online looking for answers and found
that a lot of people were having the same problem with this E3D all-metal setup. We
tried a lot of different things: higher temperatures, lower temperatures, retraction
settings, updated the firmware, bed leveling. Shortening the retraction made it a little
better but the result wasn’t as it should be yet. On a few forums people suggested
‘seasoning’ the hot end; dipping the filament in some olive oil (or other oil) and then
pushing it through the nozzle. This creates a small film inside of the nozzle so the
PLA gets through easily. At first we thought this was a joke but after thinking about it
this actually made sense because PLA is made of corn. In the kitchen when
something is cooked oil i also used for not sticking it to the pan. So we tried
‘seasoning’ the hot end and our PLA jam problem is solved.
Fig. 47 PLA jam problem solved after seasoning the hot end
37
4.1.3. Calibrating the Printer
Before we started printing with two extruders we decided to first test each extruder
individually. For calibrating the steps/mm on each extruder we used Triffid Hunter's
Calibration Guide (Fig. 48 & Fig. 49) [32]. This is the code that needs to bee changed
in the configuration.h file of Repetier Firmware to change the steps/mm:
#define EXT0_STEPS_PER_MM 836
#define EXT1_STEPS_PER_MM 135
As you can see, after calibration, extruder 1, which feeds the 3mm filament, was set
to 836 steps/mm and extruder 2, which feeds the 1.75mm filament was set to 135
steps/mm.
Fig. 48 Flowchart for calibrating steps/mm
38
Fig. 49 Flowchart for fine-tuning steps/mm
Fig. 50 A part used for fine tuning steps/mm
39
4.2. Dual Extrusion with the UMO
We encountered a lot of problems while trying to print the dual extrusion system we
installed on the UMO. Our system to control the height of the nozzles is not precise
enough resulting in a lot of prints being scratched or pulled loose because of height
difference between the nozzles. Because we installed two different diameter sizes of
nozzles in our system, something we have never seen on any other printer, we
suspect the slicing software confused the feed rates of the different nozzles
resulting in a lot of tests with signs of over and under extrusion. We also had a lot of
oozing issues. We tried to solve this within the slicing software. A few options we
tried were extensive retraction distances on a tool change, this helped a little but
didn’t completely solve the problem. In Slic3r, a slicing program we used, there is an
option to cool down the inactive nozzle after a tool change and before the active
nozzle starts extruding, this solved the problems of oozing but brought some new
problems with it: a print takes about five times as long to print and the nozzles were
clogged all the time, especially when using the conductive material. With the Cura
slicing engine an ooze shield can be added. This is a thin shell that is automatically
printed around the object shielding it from oozing nozzles. At the moment of testing
the dual extrusion system on the UMO the Esun conductive filament was the only
conductive filament we could get our hands on. After some basic tests this material
appeared to be really difficult to print with. The material doesn’t like to stick to the
HBP or to other materials, it has severe oozing problems and leaves a lot of residual
material in the print head, which causes a lot of print head jams and was also a big
problem when we used the temperature switch technique in the Slic3r software.
When printing the material together with other materials a lot of warping occurred.
After weeks of tweaking and tuning both hardware and software without any
significant progress we abandoned this path and decided to look for a different
solution.
40
Fig. 51 A number of test-cubes used for calibration on the UMO
Fig. 52 Calibration prints on the UMO
41
Fig. 53 Over extrusion on the UMO
Fig. 54 Over extruded traffic cone printed on the UMO
42
Fig. 55 Oozing problem of Esun Conductive Filament
43
4.3. Dual Extrusion with the Prusa I3
After installing the Dondolo Dual Extrusion system on the Prusa I3 (Fig. 56) we
immediately received a lot better results than our attempts with the UMO. We started
off by printing with PLA. We found a design on Thingiverse that was better suited for
calibrating the distance between the two nozzles: ‘the ‘Dual Extrusion Calibration
Print’ uploaded by walter [33]. A problem that occurred was that the material that
rested inside of the inactive nozzle would heat up and become very liquid, leaving a
drip mark on certain prints (Fig. 62). We solved this by adding a 10mm retraction
before a tool change in the slicer software. Another problem we had was that the left
idler didn’t give enough clearance space when the left nozzle was inactive causing
the filament to be pulled up while the right extruder was extruding (Fig. 63). After
measuring and testing we discovered this was caused by a deformed part that
limited the movement of the left idler. We decided to reprint all of the extruder setup
parts. We redesigned the rocking clamp which provided the idler with some more
clearance space when inactive and decided to redesign the idlers themselves
enhancing the spring attachment points which allowed for more spring tension (Fig.
64). We also opted to use M3 bolts to hold the spring instead of the original printed
fixations. The next problem we were confronted with was that when printing with the
dual extrusion system whenever a tool change occurred, meaning that the printer
switches from one extruder to the other, it took some time (or length) before the
active nozzle printed consistently. We solved this by using the Cura slice engine in
Repetier Host, which gave us the option to include a ‘wipe and prime tower’ in the
prints. Before each printed layer the nozzle is sent to extrude a square outside of the
printed object until the nozzle prints the material consistently. After the square is
drawn the nozzle makes a small rapid movement over the square to wipe the nozzle
clean. When all the squares are printed on top of each other this results in a tower
hence the name ‘wipe and prime tower’. Cura engine also gives the option to include
an ‘ooze shield’. This is a thin layer that’s printed around the object before printing
the object’s layer providing a shield for possible oozing that might occur (Fig. 65).
44
Fig. 56 The Dondolo Dual Extruder installed and running on the Prusa I3
Fig. 57 Side view of the installed Dondolo Dual Extrusion System
45
Fig. 58 A view of the cable chain and the PCB cooling fan
Fig. 59 Dual Extrusion Calibration test when not calibrated properly
46
Fig. 60 Several calibration tests for trying to get the XY allignment just right
Fig. 61 Dual Extrusion Calibration in PLA(left) and ABS (right) when properly calibrated
Fig. 62 A drip mark on a PLA print (left) and a calibration print (right)
47
Fig. 63 Difference in clearance between right and left idler
Fig. 64 The redesigned dondolo extruder
48
Fig. 65 Prusa I3 printing a traffic cone with a wipe and prime tower and an ooze shield
49
4.4. Dual Extrusion Guide
This section will be a guide for using dual extrusion with Solidworks and Repetier
Host.
Fig. 66 First model the part in Solidworks you want in one type of material
Fig. 67 Next model the part you want to print in the other material. Remember not to merge it with
the other object
50
Fig. 68 This is your part with different solid bodies for each material
Fig. 69 Right click on a solid body you want in a different material and select delete/keep bodies
51
Fig. 70 Select all bodies you want to delete and click OK
Fig. 71 Now you are left with the pieces in one material
52
Fig. 72 Save this part as an STL
Fig. 73 In the delete body feature select the pieces in the other material
53
Fig. 74 Now you are left with the piece in the other material
Fig. 75 Save the other part as an STL giving it a different name
54
Fig. 76 Open Repetier Host and adjust the printer settings. The X and Y offset can be found using a
calibration piece
55
Fig. 77 Click the + button to add the STL files
Fig. 78 Select both STL files and click ‘open’
56
Fig. 79 With the STL files imported click on the settings button of the first object
Fig. 80 Adjust the assigned extruder and set both objects in the same object group to merge them
57
Fig. 81 Press the rotate button to oriëntate the object correctly
Fig. 82 Oriëntate the object and double check the assigned extruders
58
Fig. 83 In the slicer tab select the slicer engine you want to use. We like CuraEngine. Click on
configuration
59
Fig. 84 Adjust the settings accordingly. These are the settings that gave us the best results.
Fig. 85 In the filament tab make an entry for each different filament you are using
60
Fig. 86 Adjust the settings in the slicer tab and click ‘Slice with CuraEngine’
61
In the preview tab you can see the estimated time and filament length required
Fig. 87 Connect the printer and press print or save the Gcode file to an SD card
62
5. Printing with Conductive Material
5.1. Esun conductive filament
5.1.1. Controller with Makey Makey
With the dual extrusion system up and running on the Prusa I3 we could finally start
3D printing with conductive material. We started off with printing a small controller,
which we hooked up to a Makey Makey to control the arrow keys of a PC. The case
of the controller was printed in ABS and the buttons were printed with the Esun
Conductive Filament. It was not a clean print but it worked.
Fig. 89 The combined STL file of the controller
Fig. 90 Controller in ABS and Esun Conductive Filament
63
5.2. Proto-Pasta Conductive PLA
We had much better results printing with the Proto-Pasta Conductive PLA. It binded
really good with regular PLA so it was much easier to print.
Fig. 91 Proto-Pasta and clear PLA printing on the Prusa I3
5.2.1. Capacitive Touch Wheel
We printed a capacitive wheel pad similar to the wheel that’s used in the first
generation of Apple’s Ipods. To control it we used an MPR121 Capacitive Touch
Sensor Breakout Board and an Arduino. This wheel pad could be used to control
music, light, video games and much more.
Fig. 92 The STL file of the buttons
64
Fig. 93 The prusa I3 prining the capacitive touch wheel
Fig. 94 Testing the capacitie touch wheel
65
5.2.2. Capacitive Touch Sphere
We printed half of a sphere with integrated touch surfaces. Most capacitive touch
pads we see today are limited to a two-dimensional plane. With the possibility of
printing any shape you like with a 3D printer the touch pads or touch surfaces can be
used in any shape. In our example the object becomes the touch pad. We used our
‘capacitive touch sphere’ to control integrated LED lights using an MPR121
Capacitive Touch Sensor Breakout Board and an Arduino.
Fig. 95 Combined STL file of the capacitive sphere
Fig. 96 Picture of the capacitive sphere controlling LED’s
66
6. Conclusion
In this thesis we looked at two different techniques to print conductive and nonconductive materials simultaneously. Although not fully optimized the second
technique showed significantly better results. We spend a lot more time on getting
the dual extrusion technique working than we initially planned at the beginning of
this research. It proved to be the biggest challenge we had to face. The first
conductive filament we tried was very difficult to print with and had a fairly high
resistance making it not useable for printing electrical circuits yet. The next material
we tried was already a big improvement and a step in the right direction. While the
conductive materials we tested can already be used for applications that require very
little current or for sensors we think that with further development of the conductive
printing materials and optimized dual extrusion systems the opportunities of printing
circuit structures with FFF machines will evolve rapidly. The results of this research
already shed a light on what the future of printing with conductive material might
offer. In a next phase research could be done to optimize the formula of conductive
materials so they have less resistance and can be used for printing fully functional
circuits.
67
7. References
[1]
“Dimension 1200es 3D Modeling Printers| Stratasys.” [Online]. Available:
http://www.stratasys.com/3d-printers/design-series/dimension-1200es. [Accessed: 27-May-2015].
[2]
“Ultimaker 2 | Ultimaker.” [Online]. Available: https://ultimaker.com/en/products/ultimaker-2family/ultimaker-2. [Accessed: 31-May-2015].
[3]
“FDM Technology, About Fused Deposition Modeling | Stratasys.” [Online]. Available:
http://www.stratasys.com/3d-printers/technologies/fdm-technology. [Accessed: 20-May-2015].
[4]
“Fused filament fabrication - RepRapWiki.” [Online]. Available:
http://reprap.org/wiki/Fused_filament_fabrication. [Accessed: 17-May-2015].
[5]
“Fused Deposition Modelling (FDM) | Materialise.” [Online]. Available:
http://www.materialise.com/glossary/fused-deposition-modelling-fdm. [Accessed: 17-May-2015].
[6]
“Complete Guide to 3D Printers.”
[7]
J. H. Lee, “Research: Ceramic/polymer Composite Materials through Stereolithography,” 2001.
[8]
“3ders.org - Formlabs announcing new print material: clear resin | 3D Printer & 3D Printing News.”
[Online]. Available: http://www.3ders.org/articles/20130517-formlabs-announcing-new-print-materialclear-resin.html. [Accessed: 31-May-2015].
[9]
“New 3-D Printers that Don’t Suck | WIRED.” [Online]. Available: http://www.wired.com/2012/07/3-dprinters-that-dont-suck/. [Accessed: 31-May-2015].
[10]
“What is Corn PLA plastic? | ecokloud.” [Online]. Available: http://www.ecokloud.com/what-isPLA.html. [Accessed: 27-May-2015].
[11]
“PLA - RepRapWiki.” [Online]. Available: http://reprap.org/wiki/PLA. [Accessed: 25-May-2015].
[12]
“ABS - RepRapWiki.” [Online]. Available: http://reprap.org/wiki/ABS. [Accessed: 25-May-2015].
[13]
“ColorFabb - XT Co-Polyester Filaments produced from AmphoraTM 3D Polymer by Eastman Chemical
Company.” [Online]. Available: http://colorfabb.com/xt-copolyester. [Accessed: 25-May-2015].
[14]
“Xbox 360 Wireless Controller Logic Board Replacement - iFixit.” [Online]. Available:
https://www.ifixit.com/Guide/Xbox+360+Wireless+Controller+Logic+Board+Replacement/3316.
[Accessed: 23-May-2015].
[15]
K. H. Church, H. Tsang, R. Rodriguez, P. Defembaugh, R. Rumpf, and E. Paso, “Printed Circuit
Structures , the Evolution of Printed Circuit Boards,” in Ipc Apex Expo Conference.
[16]
S. Castillo, D. Muse, F. Medina, E. Macdonald, and R. Wicker, “Electronics Integration in Conformal
Substrates Fabricated with Additive Layered Manufacturing,” pp. 730–737.
[17]
“Voxel8 Unveils New Electronics 3D Printer At 2015 CES - 3DPrint.com.” [Online]. Available:
http://3dprint.com/35085/voxel8-electronics-3d-printer/. [Accessed: 12-May-2015].
[18]
S. J. Leigh, R. J. Bradley, C. P. Purssell, D. R. Billson, and D. a. Hutchins, “A Simple, Low-Cost
Conductive Composite Material for 3D Printing of Electronic Sensors,” PLoS One, vol. 7, no. 11, p.
e49365, Nov. 2012.
68
[19]
“It’s electrifying: the paint that becomes conductive when it dries | Business | The Guardian.” [Online].
Available: http://www.theguardian.com/technology/2014/apr/27/electric-paint-bare-conductivepaintable-wire. [Accessed: 24-May-2015].
[20]
“ESUN 3D FILAMENT CONDUCTIVE BLACK ESUN.” [Online]. Available:
http://www.esun3d.net/cpxx.aspx?id=171&TypeId=15. [Accessed: 12-May-2015].
[21]
“Conductive PLA – ProtoPlant, Makers of Proto-pasta.” [Online]. Available: http://www.protopasta.com/pages/conductive-pla. [Accessed: 12-May-2015].
[22]
R. Jones, P. Haufe, E. Sells, P. Iravani, V. Olliver, C. Palmer, and A. Bowyer, “RepRap – The
Replicating Rapid Prototyper,” 2009.
[23]
M. Frauenfelder, “Make: Ultimate Guide to 3D Printing 2014,” Make: Magazine, 2012.
[24]
“Ultimaker Original | Ultimaker.” [Online]. Available: https://ultimaker.com/en/products/ultimakeroriginal. [Accessed: 14-May-2015].
[25]
“3D Printing With Nylon - 2print3d.” [Online]. Available: http://www.2print3d.com/2013/11/30/3dprinting-nylon/. [Accessed: 23-May-2015].
[26]
“Company update | Ultimaker.” [Online]. Available: https://ultimaker.com/en/community/view/10344company-update#entry90597. [Accessed: 23-May-2015].
[27]
“3D Printer Maker Stratasys Expands Automated Support-Removal Process for Polycarbonate Material
(NASDAQ:SSYS).” [Online]. Available:
http://investors.stratasys.com/releasedetail.cfm?ReleaseID=627524. [Accessed: 22-May-2015].
[28]
“Erik’s Bowden Extruder - RepRapWiki.” [Online]. Available:
http://reprap.org/wiki/Erik%27s_Bowden_Extruder. [Accessed: 21-May-2015].
[29]
“Airtripper’s Bowden Extruder V3 by Airtripper - Thingiverse.” [Online]. Available:
http://www.thingiverse.com/thing:35404. [Accessed: 23-May-2015].
[30]
“Prusa i3 - RepRapWiki.” [Online]. Available: http://reprap.org/wiki/Prusa_i3. [Accessed: 21-May2015].
[31]
“Dondolo v1.0b by franci - Thingiverse.” [Online]. Available:
http://www.thingiverse.com/thing:673816. [Accessed: 23-May-2015].
[32]
“Triffid Hunter’s Calibration Guide - RepRapWiki.” [Online]. Available:
http://reprap.org/wiki/Triffid_Hunter%27s_Calibration_Guide. [Accessed: 24-May-2015].
[33]
“Dual Extruder Calibration Print by walter - Thingiverse.” [Online]. Available:
http://www.thingiverse.com/thing:533814. [Accessed: 25-May-2015].
69
Appendix 1
Tel: 86-755-26031978
electric property
thermal property
mechanical
property
physical
property
ASTM D-256
3.2 mm
1.8 Mpa
notch impact strength
heat distortion
temperature
flammability
ASTM D-257
HB
100
354
2400
85-90
45
50
1
1.5
1.2
800
220-260℃
Better nature, better life! www.brightcn.net
surface resistivity
UL 94
ASTM D-648
ASTM D-790
ASTM D-790
ASTM D-638
Elongation at Break
flexural modulus
Tensile Strength
ASTM D-638
Tensile Strength
ASTM D-1238
ASTM D-792
Data
Black
3mm,1.75mm
0.5kg/roll
Test Standard
ASTM D-955
230oC/2.16k
g
Test
Conditon
Shinking rate
Melt Flow Index
Print Tem.
[email protected]
Data Sheet of Esun 3D Conductive Filament
Shenzhen Esun Industrial Co., Ltd.
Relative Density
Color
Diameter
Packing
Item
Contact: Kevin Yang
Fax: 86-755-26031982
Ohm
℃
J/m
Mpa
Mpa
%
Mpa
%
g/10min
g/cm3
Unit
8. Appendixes
Esun conductive filament datasheet
70
http://www.openimpulse.com
42BYGHW208 Stepper Motor Datasheet
Model
Step
Angle (
° )
42BYGHW208
1.8
Motor
Length
L(mm)
34
Rate
Voltage (V)
Rate
Current (A)
Phase
Resistance ( Ω)
Phase
Inductance
(mH)
Holding
Torque (g.cm)
12
0.4
30
37
2800
Lead
Wire
(NO.)
4
Rotor
Inertia (g.
cm2)
34
Detent
Torque
(g.cm)
200
Motor
Weight (kg)
0.2
http://www.openimpulse.com
Appendix 2
NEMA17 42BYGHW208 Datasheet
71
Appendix 3
NEMA17 42BYGH4803 datasheet
72
Class B
100Mohm
Holding Torque
Pull-in Rate
Insulation Class
Dielectric Strength
Insulation Resistance
Operation Temp Range
8
9
10
11
12
13
N/A
0.34Kg(Max)
Lead Wire
MFG of Terminal
Weight
20
21
Life
Stepping Accuracy
Rotor Inertia
Detent Torque
-20 ~ +40° C
19
18
17
16
15
Storage Temp Range
5.5Kg.cm
Current Per Phase
7
14
4.8
1.5A
Inductance Per Phase
6
± 20%
2.8 ± 10%
Resistance Per Phase
4
5
1.8° ± 5%
Step Angle
No.of Step per Revolution
NO of Phase
3
4.2V
2
Rated Voltage
500VDC
SPECIFICATION CONDITION
1
2
ITEM
4.5
C
GRN
A
B
21.0
D
BLU
24.0± 0.5
2.0
48.0Max
750
NO.
4-M3
Sara
9/2
9/2
42BYGH4803
Q.A.
MFG APPR.
ENG APPR.
Ma Yunlei
DRAWN
CHECKED
AWG22
deep4.0min
Weight(kg): 0.34
DWG.NO.
1504
Kysan Electronics
SCALE: 1.5 : 1
SIZE
A4
Revision
Update
UNIT: mm
31.0± 0.1
42.3Max
Rev.
01
31.0± 0.1
SHEET 1 OF 1
REV
01
Date
9/2
42.3Max
Ø22.0
Ø5.0
Appendix 4
Repetier Firmware changes in configuration.h for UMO
73
Appendix 5
Repetier Firmware display changes in Uiconfig.h
74
Appendix 6
Repetier Firmware display changes in Uiconfig.h
75
Appendix 7
Repetier Firmware controller keys changes in Uiconfig.h
76
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