Last time, we demonstrated that even an unassuming appliance like
a printer can be turned into a fun
fighting robot. Just as most anything
can be turned into a robot, most
anyone can make a robot with the
right mix of confidence and
An important and perhaps
sometimes neglected building block of
robotics knowledge is familiarity with
basic materials. We’ve drawn upon
our knowledge and experience with
materials in every robotics project
we’ve worked on, and knowing the
difference between 6061 and 7075
has not only made us sound like
nerds, but it has also improved our
designs and enriched our robotics
To help those looking to increase
their fluency in robotics fundamentals,
provide a useful refresher, or simply
prepare for that inevitable Jeopardy!
category on aluminum alloys, this
month we’ll provide an overview of
some of our favorite building materials
and where to find them.
You can build a robot out of
pretty much anything, but if you find
yourself debating between general
categories like wood or plastic or
metal, this is the article for you.
Having a more granular understanding
of the materials available to you helps
you make smarter design decisions
and better robots.
Perhaps it’s due to our history in
combat robotics, but our preferred
category of material from which to
make a robot is metal. Far from a
monolithic bore, the metal family is
varied, exciting, and perhaps a little
intimidating to the uninitiated.
A metal robot sounds cool, but
what do I use? Isn’t aluminum for
soda cans and wrapping up baked
goods? If it makes for good robot
boxers, should I go with steel? Or
something more exotic, like titanium?
These questions and more might
make the initial selection of a material
seem overwhelming, but a few
guiding principles can help you make
a smart selection that’s right for your
With many robotics projects, two
concerns always seem to loom larger
than the others — weight and cost.
Just like a dedicated Biggest Loser
contestant, most competitive robots
must fastidiously keep their weight
down to acceptable levels. Most
projects are also on a tight budget,
making cost an important factor.
At first blush, these concerns
may seem to rule out metallic
designs in some circumstances.
Plastic is lighter and cheaper, right?
Perhaps, but those are not
necessarily the only questions you
should be asking. For a robotics
project, a better property to look at
than weight alone is the strength to
weight ratio. A piece of plastic may
weigh less than the same size piece
of metal, but the metal piece will
have a better strength to weight ratio.
With that better ratio, it means
you can use a thinner piece of
aluminum rather than a piece of
plastic for your robot floor without
sacrificing strength. By using less
material, you save on costs because
most materials are priced by weight.
Other guiding questions that will
help you select the best material for
your robotics application are
machinability, strength, and cool
factor to name a few.
These questions can’t be asked in
a vacuum — the answers will depend
on what part of the project you’re
using the material for.
With these questions in mind, we
are ready to take a look at some of
our favorite materials that we’ve used
in various robotics projects.
First and foremost, our favorite
material to work with is aluminum.
Sure, they make soda cans and foil
out of it, but if it’s good enough for
by Bryce Woolley and Evan Woolley
Twin brothers hack whatever’s put in front of them, then tell you about it.
ALUMINUM — A GREAT GENERAL-PURPOSE METAL.
ALUMINUM — IT'S SO BENDABLE.
SERVO 10.2013 69
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