Three dimensional printing is
changing the face of science, art, history, and design. As these futuristic machines,
which can reproduce almost any physical object, become cheaper and more
accessible, creative people find new uses for them every day. Nowhere is this
more apparent than in education. Students in two Virginia school districts are
using this technology to build functional models of machines, to better
understand how they work. They’re now able to do so more quickly and cheaply
than ever before.
American Innovations in an Age of
Discovery is joint initiative
between the Joseph Henry Project for Historical Reconstruction at Princeton
University, the Smithsonian Institution, and the Laboratory School for Advanced
Manufacturing at the University of Virginia. The goals of the project are to reconstruct
important historical inventions and develop an innovative new middle school
science curriculum. The Smithsonian is creating an online database of 3D
animated artifacts called Smithsonian Invention Kits. This open source software
is being used by the Virginia students to build working reconstructions of
historical machines. The curriculum is based on Engineering in the
Modern World, a Princeton course, developed by professors Michael Littman and
David Billington. The program is
being piloted at middle schools in the Charlottesville City and the Albemarle
County Public School districts.
The goal for the students is not to simply reproduce exact replicas, but
to reinterpret and reinvent the devices with a modern twist. For example, they
may change the size or placement of parts in a device to see how that affects
its function. With 3D printing, they’re able to easily change the shape and
size of each component part, any way they can think of. Each model is designed to display and
teach a specific engineering or physics principle. Students can actually see
all the physical principals at work and understand their applications.
“We are essentially bringing the principle to life in
a clear progression. Instead of it
being just an equation on a blackboard, it becomes real for the students.”
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| This original Page Solenoid is an electric motor was invented in 1854 by Charles Page. Students use photo realistic animated designs to build working replicas of this device. Photo source: Smithsonian 3d.si.edu/invention |
The Page solenoid motor is used to
demonstrate the solenoid effect, which is the way that certain metals are
pulled into a magnetic field due to the gradient or fringing of the field. The
effect is demonstrated by switching the solenoids on and off, producing
continuous motion. Then the motor is used to perform a useful task (i.e lift a
weight, turn fan blades, etc.) Students then apply what they’ve learned and
build their own 3D printed versions of the device.
“We are essentially bringing the principle to life in a clear progression. Instead of it being just an equation on a blackboard, it becomes real for the students,” says engineer Luke Stern. For two summers, Luke worked at Princeton University, as a student researcher under Prof Littman, while perusing his engineering degree. He is now the project’s lead animator and designer. He now works from California, where he’s also starting a design business and pursuing his own research in 3D printing and engineering.
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| This is a CAD rendered reinterpretation of the Page motor, created by Luke Stern ,lead designer and animator on the American Innovations in an Age of Discovery project. The purpose of this particular model is to teach students about the solenoid principle. Picture courtesy of Luke Stern |
He uses computer aided design (CAD)
to model the devices before they can be printed. Additionally, he makes 3D
animations to be used in lectures. A few of these educational materials have
been used in various engineering courses at Princeton University.
Some of Luke’s designs are simply
reinterpretations of existing machines, but he also makes his own original devices.
So far, he has developed a 3D printable loudspeaker, a microphone, a gear pump,
a drop tower catapult, and a pendulum clock. He is currently in the process of
building a website, Princeton Concepts,where plans for all of these things
will be available. He hopes to have it online by the end of March 2016.
"To be able to replicate something that easily, which cannot only produce noise, but can sound quite good, I believe, can be very inspiring to young engineers,”
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| Many designs Luke creates are distinctive 3D printed versions of existing inventions. They are similar to their historical counterparts, but not exact replicas. An example is his Galileo Pendulum which is a scaled down version of the original clock mechanism invented by astronomer Galileo Galilei. Picture courtesy of Luke Stern |
One of Luke’s original designs, is
a speaker that is fully 3D printable. The particular challenge here was to
produce something that both sounds good and
uses parts that are made exclusively out of one plastic material. He says it’s
difficult to design something that is both easy to print on any machine and
also performs well. For example, it took several attempts to perfect the cone,
the part of the speaker which vibrates to produce the sound. He had to test
many different prototypes before he finally got it right. “For any individual
to be able to download the files and print or modify them to their own custom
version is remarkable. To be able to replicate something that easily, which
cannot only produce noise, but can sound quite good, I believe, can be very
inspiring to young engineers,” he said.
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| A fully 3D printable speaker: "One particular advantage of using 3D printing to design and manufacture the speaker is that one can very easily and quickly experiment with different cone shapes. Different shapes will give you different mechanical stiffness, which affects the frequency response of the speaker. This concept could be incorporated into a very interesting undergraduate engineering exercise," Luke says. Picture courtesy of Luke Stern |
The design
process involves plenty of trial and error. For the educational models he begins
by video conferencing with professors at Princeton and the University of
Virginia. They identity a valuable engineering concept or device they want to
develop. Next, Luke thoroughly researches the concept in order to get all the
information needed, to make a proper design. He then draws up sketches in his
notebook to visualize the best approach for a 3D printed design. Then he begins
to model parts on CAD (computer assisted design) software. He’ll sometimes
start by printing one subcomponent to make sure it’s workable. Other times, he
draws out almost every component in the assembly before prototyping it. It
depends on whether or not the device uses all 3D printable parts.
“In my designs, I try to
incorporate as many 3D printed parts as I can, because the more 3D printed
parts, the easier it will be for anyone with a printer to manufacture.” It
usually takes around eight to ten hours to print a device on his printer.
After he has the first printed
prototype, he then goes through a trouble shooting process of design changes
and reprinting, until he has a device he’s happy with. He also makes videos of
the devices and educational animations of them for University of Virginia to
use for their school curriculum program.
Animation can be a time consuming
process. “When you do photo realistic animation, the render times are
outrageous because of the ray tracing that’s required…It’s a very CPU intensive
process,” Luke said. Even with a powerful computer, it can still take about two
hours to render one second of video. But
it does depend on the complexity of the model and the video resolution. The
page solenoid motor animation on the Smithsonian website took 2-3 days to do.
He made three different versions of it.
Luke uses a variety of different
animation and CAD software to produce the animations. To draw everything, he
uses a program called Creo Parametric. This is what he used to create the photo
realistic Page motor simulation on the Smithsonian website and the videos on
his You Tube channel. He also uses Keyshot to produce photo realistic
animations. He does the final video edits in Adobe Premier Pro.
About 80-95% of each device Luke fabricates
is 3D printed, usually from a type of plastic, such as PLA (polylactic acid). It’s
possible to print with lots of different materials, including various metals
but, Luke prefers this type of plastic. “It’s cheap, ridged, true to form, and
biodegradable,” he says. The printed plastic mainly serves as physical
scaffolding for a device. Other parts that can’t be printed or made of plastic,
such as the magnet wire in the solenoid motor have to be ordered from an
outside supplier. Certain parts may also be cut with a die cutter or a laser
cutter.
The educational models usually have
a non 3D printed design component incorporated into them, which enables to
students to change something about the device. For example, they can change the
windings on the solenoid motor to see how that affects its performance. “Many
times there is also an integration of standard off the shelf mechanical
components to increase the performance of a device. For example, using standard
steel pins to reduce the friction in the Galileao Pendulum pivots. “Some of
what we do is exploring inexpensive standard components that can be easily
added to a 3D printed design.”
“You really
haven’t designed something well
unless your grandmother can make it.”
Luke wants every device
he designs, to perform well, while still being fully printable, and easy to
replicate. “A good designer or engineer doesn’t just come up with a cool device
or component in 3D, he/she should be able to make sure that device can be
properly manufactured,” he says. He strives for simplicity. Luke refers to a
famous Albert Einstein quote, “You really do not understand something well
unless you can explain it to your grandmother.” Luke says, “You really haven’t designed something well unless your grandmother
can make it.”
Below is a sampling of some of Luke's projects. His main You Tube channel is LS Concepts. For More information about American Innovations in an Age of Discovery, go to http://3d.si.edu/invention
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| CAD rendering of a 3D printable microphone |
