12
User Manual
Arduino Materia 101
Before you start printing with your
Arduino Materia 101, it is important to
understand how you arrive at a finished
object. This allows you not only to know
what you need to do to give form and
substance to your ideas, but to identify
any constraints and limitations of the
technology used by the printer.
In the table (Fig.1, page 17) the steps required
make successful 3D print are summarized.
mOdel
It all starts with creating or downloading
a three-dimensional model of the object
that you want to print. The creation is
done through one of the many modeling
programs available over the internet as
freeware, shareware or software for a fee.
There are many and each of them has
different characteristics. In this respect it is
worth noting that you can have different
modeling requirements and this is reflected
in the variety of applications. Some are
more suited to mechanical design, artistic
modeling, and others for architectural design.
Remember that 3D modeling is primarily
used to create objects that either a machine
can make or for 3d rendering of a 2D
animation or picture. In the first case, the
object is designed to be made in the physical
world and should therefore be subject to
certain limitations that are taken for granted
in the “real world”. For example that a cube
needs 6 sides to be a cube. In the latter,
the aim is to create an image or animation,
nothing more: the model might then be
flawless as a image, but might be physically
impossible to print.
When you choose the program that you want
to use for your models, you must ensure
that it is able to create a file suitable for the
production of a physical object (especially
3D printing). The programs that are made
for rendering and animation might not be
suitable for making 3d printed objects.
dOWnlOading frOm
internet
The net offers many ready-made 3D models,
but there is a difference between the models
that “look good” and those that “print well”.
A good indicator of an object that is
printable is if it is offered in the STL-
format (sites that share or sell printable
objects often use this format).
If there is no STL-file, it is likely that
the intended use of the object is
something besides 3d printing and
the results can not be guaranteed.
frOm a 3d mOdel tO
a Printing file
The real “secret” of three-dimensional
printing is the transformation of the
three-dimensional object into a sequence
of two-dimensional slices that, through
overlapping, reconstruct the object. Imagine
a series of slices of bread: The stack rebuilds
the loaf from which they were cut from.
In the case of 3D-printing every slice may
consist of two-dimensional shapes not
connected together, because it is their
addition to the layers below and above
that will amount to a finished object.
Thanks to this breakdown, the objects can be
as complex as desired. The printer will draw
one layer after another without overlap. A
layer shaped like a square or a doodle have
the same difficulty for the printer.
The postprocessing-program takes a bunch
of parameters and applies them in the
process of cutting the 3d model into 2d
slices. This process is simply called “slicing”
and programs that do this are called “slicers”.
To be able to this in a proper manner the
slicer needs a mesh of surfaces shaped like
triangles in 3d space. The mesh has to be
closed and not have any surfaces missing.
The triangle faces should be correctly
oriented, not confusing the “insides” with
the “outsides”. Sometimes the model is
incorrectly made. If it is a small issue, for
example a missing triangle, the program
might be able to fix the issue. Otherwise,
the resulting errors might prevent the
correct reproduction of the object.
a gOOd stl,
a gOOd slicing,
a gOOd Print
The STL file is the starting point for the
entire procedure, so anything you do
not want to print should be removed
from the file (hidden objects, etc.).
The 3D drawing must be a solid, not what
only appears to be a solid. Similarly, the
design must be as clean and precise as
possible. Articles must have an inside and
an outside that are well defined so that the
surfaces perfectly match each other without
leaving holes. Most 3D design software gives
you the possibility to carry out an analysis
of borders to check for holes.
The 3D drawing must be oriented in such
a way as to have a face adjacent to the
XY plane of your drawing software. In
other words, the design should not “float
in a vacuum”, otherwise the machine