Year 6 So Far

Boy howdy, do I have something to blog about! Beware, there be engineering geekyness ahead.

So, I'm on my SIXTH YEAR of teaching. I don't know how that happened. So far, it's been a really busy year. I'm back to teaching just 6 periods (as opposed to 7 without a free period like last year), but I have four difficult subjects right now--Exploring Technology (8th Grade), CTE Intro (7th Grade) (3 periods), Keyboarding (8th Graders), and Intro to Engineering (9th Graders). All my classes are fairly full, and I have pretty awesome kids. There's a bunch of kids in Engineering that confuse me though. I have mostly engineering-bound kids who are nerdy and wonderful and just want to learn, and then I have a handful of lazy, slow kids who apparently thought a class with "engineering" in its title would be EASY. I often have to re-teach everything to them, one at a time. And then they STILL don't get it. Whatever.

So anyway, year 6. We have a pile of money that needed to get spent in our class fee fund (or else our principal will spend it), and I decided to go for something that I've wanted for years: a 3D printer. The day I decided I was going to buy one, I got so excited I had to tell my 9th graders. The excitement they projected at me was pretty awesome. So I spent the weekend researching, and ended up choosing the Solidoodle 3rd Generation.



Not really the most advanced, best-all-around printer, but no one else could beat the price. If I liked it, I could buy a bunch of them and really have a factory going. Besides, I'm a middle school teacher teaching the most basic, introductory engineering class ever--we did not need the latest and greatest technology, just something to whet their appetites for the high school program.

(And also to draw more kids into my program. I plan to play very, very dirty during registration season this year)

Anyway! The Solidoodle. Once I got this thing out of the box and connected to the computer, I was printing within the hour. The way it works is pretty cool.
1. Load a 3D Model (.STL format) into the printer software. The computer converts it into a giant list of coordinates, telling the extruder where to extrude filament.
2. As the print job runs, you can watch the printer's progress on the computer.
3. There's a spool of ABS plastic filament mounted to the back of the printer. That feeds into the extruder, which melts it and then pushes it out onto the print bed.
4. It builds the model from the bottom up, 1 tiny layer at a time. The print resolution (layer thickness) was set to .1mm here.

My first print was a giant failure. You can really see the layers of filament in it--for some reason, there wasn't enough heat to get the plastic layers to melt together. The next one turned out fine, though. I made a couple of boxes to figure out how the scale going from my CAD program to the printer software worked.

Then I went to thingiverse.com and found a jackolantern to print. I made FOUR attempts, and each one failed, for various reasons. In this picture, you can see the honeycomb pattern the printer uses for the center of a solid object--it saves on filament.

I determined that I could not babysit my machine and teach at the same time. Luckily, Fall Break was upon me. I took the printer home over the long weekend, and spent the entire weekend fighting with it (sorry Mom and Dad). But in the end it was very worth it, because I figured out all kinds of stuff. After many many fails, I found this Torture Test on the Solidoodle Tip Blog. I tried printing it, so see if the blogger's results matched mine. (And by the way, a torture test is just something to test a printer's capabilities--it's supposed showcase challenging print jobs)

That torture test was truly torture--it took over four hours for the dang thing to finish printing. So I designed my own torture test instead. An arch, and a bridge. Something simple, that wouldn't take long, but with some mega challenges. The printer handled the bridge okay (there were some droops), but the arch was a complete failure. Then I decided to change the print resolution from .1mm to .3mm. The printer went MUCH faster at .3mm, and it even managed to print the arch (sort of). Below you can see the resolutions side by side:

The figure on the left is the lower .3mm. The figure on the right (with the ultra crappy arch) is the .1mm. This test was encouraging. I started printing out scaled-down models of the CAD playground from my Engineering class. My students are learning CAD right now, and ultimately, they will design their own playgrounds. I really REALLY want to print out 3D models of their designs to put in the display case! Below on the left is an example of warping--the print bed is heated, so the longer the figure sits on it (sometimes hours depending on the print job), the more it warps. Dad helped me solve that problem! And on the right is the printer "bridging". This yellow thing is the tube slide for the playground.

And then I had to go through several attempts at printing the spiral slide (it required a lot of support material). Here's the finished playground:

The shop teacher happened to have some mega wood shavings in the trash, so I pilfered some for the "mulch". My kids LOVE this. They can't get enough of 3D printing! And neither can I, apparently. I didn't really have a project going on the printer yesterday, and I felt sad about it. But then I got a package in the mail:


Early on in my 3D printer research, I requested a sample from a company called Stratasys. The sample finally came, and it was a twisty-hexagon bottle with a threaded lid. Very high quality. I decided that I would use the sample as a quality control--if I could replicate it with my Solidoodle, then I made the right decision to go for an inexpensive printer. So all day today, I printed out little hexagony bottles.
1. Was a CAD error. I messed up on the thread--it was way too tight, and I couldn't get the lid on the bottle. Then I left it at my desk and some helpful child forced the lid on it. I couldn't get it off, and thus broke the bottle itself in half.
2. Was better on the threads...except I put them on backwards. So that bottle ended up with a lefty-tighty, righty-loosey lid. Whoops!
3. Got the threads right, but I still wasn't happy with the print quality.
4. Messed with some printer settings and added an enclosure to keep out cold air. This one definitely approached the quality of the Stratasys Sample.


Overall, I'm quite happy with my 3D printer, especially now that I have got so much figured out. The learning curve was brutal though!

...so for Christmas...expect to see a lot of homemade stuff this year. :)

One more thing: I'm teaching Keyboarding in my lab this year, and I am lacking a lot of the stuff that goes with it--like those fancy plastic keyboard covers. Rather than order more and have them constantly in the way, I designed my own:
Inspired by The Oatmeal.