Saturday, November 01, 2014

Tinkering with Tinkercad

When I first started out as an architect, personal computers were just hitting the practice; small offices were just starting to give CAD (computer aided drafting/design) a try. Now, we have 3D modeling in the cloud. It's rather astonishing.

Even more astonishing, modern CAD software now outputs to 3D printers. I made this little test house to see how to link and embed a model made from geometric primitives in Tinkercad. I then exported the model as an .stl file and printed it.

Tuesday, September 23, 2014

STEAM Engine

Our rallying cry for the new Science and Innovation Center has been STEAM (Science, Technology, Engineering, Art, and Math), and now the class has had the chance to stand at the confluence of a few of those subjects. Our physics teacher, Jon, has asked us to print out a few parts for a Stirling Cycle Engine - a highly efficient, closed-loop engine.

The class arranged the parts on the build plate in two sets - the first set pictured here; parts were downloaded from Thingiverse. You can clearly see the cylinder body along with other parts - the Stirling uses a "displacer" as well as a piston; the top of the displacer is the larger disk opposite the cylinder body on the build plate.

The Stirling uses the difference in temperature between the gases in the chamber and a pair of plates, which are the aluminum parts mentioned in the video - there is a hot plate (on the bottom) and a cold plate (on the top); a variety of energy sources can be used to create the temperature differential. Once the flywheel is set in motion, very little energy is needed to keep the engine running.

The whole thing makes more sense if you download and study the assembly drawings. We'll release and clean the parts and give them to Jon's class. Can't wait to see the thing in action.

Sunday, April 20, 2014

MakerBot Replicator 2

A couple of years ago, MakerBot took a turn from making 3D printer kits and printers that looked like kits, to "mature products". It introduced the Replicator 2 in 2012, as their first real attempt to make a salable consumer product - for about $2200. The Replicator 2 got rave reviews and seemed to spark the market for "pro-sumer" devices, as the number of competitors seems to have swollen in the meantime. And this new class of devices has now found their way into homes and schools everywhere.

This year, MakerBot introduced their latest "5th generation" products, and the price for the Replicator 2 dropped to $1899 - too cheap to ignore. So I went to the Microsoft Store and grabbed one. Set it up, pushed some buttons, and it's very easy to get started - really impressive how easy it is to get started. I printed a couple sets of the nuts and bolts on the provided SD card. Piece of cake.

But there are nuances and issues. My idea is to teach a technology class as an art (architecture) class, so I tested the printer by printing a model of the house, and the steep, curvy contours of the landscape made a giant mess - the extruder never stops extruding, and drags a thread of plastic every time it has to "cross a valley", thus filling the valley. After the printer finished, I had to go back and clear out these threads, leaving lots of funny edges and bumps.

There is also an on-going balancing act going on in the hobbyist community between getting the plastic to adhere to the build plate during the printing process, and releasing the printed object when finished. It involves: blue painter's tape, kapton tape, isopropyl alcohol, acetone, hair spray, glue sticks and other household cleaners and chemicals - or some combination thereof. The basic process I've started with is to lay down blue painter's tape on the build plate (made of acrylic), and clean it with the alcohol between renderings.

The other battle going on is a search for a solution to the curling of the plastic as it cools. The nuts and bolts are about 3/4" in diameter, and I had no problem printing them directly on the build plate. When I first tried a larger print (4-in square base) without the tape, the plastic peeled up at the corners, and began rocking back and forth as the extruder crossed the area. The tape does not prevent the curling, but seems to keep the print job in place, holding the edges steady to get a better render.

I've also found that by turning the model in the software, you can get the extruder to cross the "valleys" in different ways, so it's worth checking the "print preview" to see which position gives the cleanest render.

Any way, there is much more "art" to this process than it might seem. Regardless, it's an amazing technology.

Saturday, March 15, 2014

A Week of Science

Science is awesome. Scientists are awesome. I've been binge-watching Neil dGrasse Tyson YouTubes since Sunday.

On Sunday, Dr. Neil deGrasse Tyson hosted the re-launch of Cosmos, a beautiful re-visioning of Carl Sagan's 35-year-old original; both open on a sea cliff near Carmel, CA, so there's kind of a local connection. Dr. Tyson flew around in a little capsule that reminded me of a cross between Flight of the Navigator and Count Dooku's solar sailer from Star Wars (I don't recall seeing the outside of Sagan's ship): fantastic imagery and story-telling. Can't wait for episode 2. Way better than Downton.

On Monday, Dr. Randy Schekman, cell biologist and Nobel laureate, gave this year's Brizendine Visiting Scholars talk about protein secretions in yeast cells. Nerdy? You bet, but not unfathomable. Dr. Schekman traced the path of proteins thru a series of organelles inside a cell, and described the process he explored using yeast cells. I asked my co-worked what he thought, and he said, "He lost me." Hmm. Not a real nerd.

On Wednesday, Dr. Dan Siegel, psychiatrist and professor at UCLA and founder of the Mindsight Institute, spoke about being an adolescent. Speaking as he was to an audience full of adolescents, he carefully crafted a description of the adolescent brain and the changes in development of the various structures inside it. He used a kind acronym of "essence":

  • emotional spark, social engagement, novelty, and creative exploration

to frame the areas of brain growth that are happening - not as nerdy, but illuminating for students and teachers alike.