ReplicatorG software converts a digital 3-D model into G-code for
printing. Image courtesy of MakerBot Industries.
William O’Dell designs and prints RC parts for
airplanes. This is one of his custom, three-blade spinner designs. Photo courtesy of
See additional photos here or online
at www.ModelAviation.com/3Dprinting. reduce the ability to print finer details.
Another point to consider in material selection is
recyclability. A roll of filament might not seem expensive
at first, but after a few dozen prints, the costs add up. Some
innovative designers have turned to creating their own
filaments with DIY filament extruders. The extruders melt
either raw material or recycled material and then extrude the
filament into a strand ready for the printer.
Now let’s discuss software and CAD, CAM, and G-code.
This is the part where many people’s eyes glaze over with fear,
but don’t be afraid. 3-D printing has also led to simplification
in the world of 3-D digital design.
Whether you are designing your own objects or
downloading them from the Internet, you will need a 3-D
CAD software package. A few years ago, decent 3-D CAD
software could cost you hundreds or thousands of dollars and
take weeks to learn how to use. They still cost that much if
you want to design critical systems for your profession, but for
the rest of us, 3-D CAD is often free and easy to use!
Autodesk has been working hard with the 3-D printing
community to ensure that. Its latest acquisition, Tinkercad.
com, means that in a few short minutes you could design
a 3-D, ready-to-print object. Other excellent free choices
for 3-D CAD include 3DTin.com, SketchUp, OpenSCAD,
Wings 3D, Scupltris, Autodesk 123D, Blender, POV-Ray, and
FreeCAD. Of course, you can use any professional 3-D CAD
After you’ve designed your 3-D object, you need to export
it to a STL file. STL is not the only choice, but is the most
widely used format for printing stereolithographic CAD files.
Depending on the printer you are using, the next step is to
prep the STL file
for print using
software such as
will slice the file,
3-D object into
layers. It will also
generate a G-code
file which uses
and special codes
to tell the printer
what to do.
Those who have
done any CNC
laser cutting will
recognize G-code which dates back to the 1950s. After the
slicing is done you are ready to print. Click print and watch
your object come to life.
With 2-D ink printing, the type of printer, the ink, and the
paper influence the quality of the final print. A dot-matrix
printer isn’t expected to create high-quality photos, and the
same is true of 3-D printing. Use the right printer for the right
3-D printing has limitations that are a result of the size and
resolution of the printer and the characteristics of the printing
material. A low-end, hobby-grade, 3-D printer can generally
produce detailed, complex objects.
As with a dot matrix printer where you can see the dots
that make up the print, 3-D printing has a resolution as well. If
you look at the object closely enough, you can see the visible
layers of the print. The surface is not smooth. With a higher-end printer and by spending more money, you can get a better
To save a few dollars and for prints in ABS plastic, the
surface can be smoothed out with acetone. Some people
dip and brush acetone to smooth the prints. A more popular
technique involves a heated acetone vapor chamber that
slowly melts the layers into a glossy finish.
Perhaps one of FDM printing’s biggest limitations is the
amount of color variations. Single-head printers mean that
only one material can be fed through at a time. Some new
designs are begging to incorporate two, three, or even four
heads so that multiple materials can be used in a print.
Full-color printing, such as the prints from 3D Figureworks,
requires high-end, six-figure machines.
As with any creative group of people, designers have found
that limitations do not mean barriers. Many of the 3-D
printing materials can be dyed using readily available fabric
dyes. Of course, you can always paint your object, as you
would any plastic model or part.
For aeromodelers, 3-D printing opens up a world of
possibilities. A scale builder could design scale details from
original blueprints and print them out on his or her desktop.
Multicopters have developed in the same era as 3-D printing
and many multicopter designs and parts are printed on
workbenches around the world. Many of those multicopter
part designs are shared freely online and you can download
the digital files and print out your own parts. 3-D printing is
shortcutting the process from idea to flight.
When I think of the possibilities for 3-D printing, I get
excited. Imagine you are getting your airplanes ready on a
58 Model Aviation OCTOBER2013 www.ModelAviation.com