"Building stuff requires planning, trying, and yes, failing, then trying again. These are incredibly important mindsets for today's world"

Karen Cator, chief executive of Digital Promise

I've been so impressed how quickly our SEP classes picked up the ins and outs of Tinkercad! None of my 28 learners had ever used it or any other CAD (computer assisted drawing) application and given their ages (9-10 year olds), a testament to their open curious minds and Tinkercad's intuitiveness. And that Tinkercad is so compatible with various platforms and project intentions (Scratch, Minecraft,  Catch) for both 3D printing and 3D file export, it was inspiring to see how kids developed their interests to make their project planning their own. For those interested in 3D printing, they prepared individual projects using the SEP medal demo template. As I opened the first class, your Tinkercad design planning for a 3D print job is very different from a project design solely for exporting a 3D file to another platform (such as Minecraft). 3D printing requires very exact designing and given the state of 3D printing (emerging), simple and small scale designing is your best bet and no guarantee of a successful print job, even with careful planning. For example, I tested the SEP medal demo for class use and successfully printed a job using it on an Ultimaker2 3D printer. However, sending this same project file to the UVa Mechanical Engineering Afinia printer, it failed, warping. When you teach emerging technology like 3D printing, though, the failures are often more instructive than the successes! And we'll spend the next session discussing the important differences between these 2 printers:

The Ultimaker2 read my g-code file in a way that allowed it's programming to re-size it to an optimal size (6 x 7 mm) to ensure a successful print. The Afinia printer did not have that capability and printed exactly the size designed (81 x 81 mm).

The Ultimaker2 print bed is "enclosed", meaning it has a protective covering surrounding the print bed that keeps the temperature uniform during the build. The Afinia printer does not have an enclosure surrounding the print bed, and therefore, it is sensitive to temperature differences between the extruder, the build area, and the surrounding room temperature. This will cause warping, where the project curls up and eventually gets in the way of the extruder to block printing progress.

The Ultimaker2 reads the 3D print job from g-code; the Afinia printer reads the job directly from the .stl file. How the 2 printers approached the job itself was very different, and I suspect the g-code may help a printer define the optimal extrusion sequencing. The Ultimaker2 printed the project in quadrants after defining the first layer project circumference, whereas the Afinia printed each layer following the entire project circumference. Researching user feedback about warping, I learned that the more weight the extruded material has, the less likely warping occurs. So, printing in quadrants "cements" each layer of a section while the extruded material is still warm, whereas printing layers following the entire project outline leaves time between layers so that it cools unevenly, hence, sides can warp before the next layer passes back over from the extruder depositing filament that is warmer than the first layer.

I've submitted a re-sized SEP Medal demo project to the Mechanical Engineering team to see if changing the size of the job helps reduce warping? So, our 3D printing lesson plan now includes scientific inquiry, full of dependent and independent variables, and hypotheses, ultimately a more valuable learning experience than clicking "print>ok" and retrieving the perfect print in 2 hours.

Next, I tested the 7Tech 3D printing pen we'll use in class so kids can "be" the extruder, and apply some of the design principles they've learned in Tinkercad, such as breaking complex and/or delicate projects into separate components assembled post print. In this case, the class project is to create a snowflake that stands on its own. There's a lot out there both by checking user reviews on Amazon, and social media like Reddit for ideas about using 3D printing pens to teach 3D design principles. First try, my 7Tech pen allowed me to design this without any issues:

Our class projects will involve teams of 2 kids with an instructor creating a 2 element snowflake:

1. Draw the snowflake on a graph paper template on a horizontal plane
2. Draw the stand
3. Make the project vertical by assembling the 2 parts, using the pen to stick the snowflake to the stand.
4. From a video taken by the instructor of the snowflake being drawn, the partner in the team not drawing will create "g-code", x-y-z coordinate instructions that describe how the design occurred.

Then, the partners will switch; the g-coder will become the drawer, so each gets a chance to experience the steps an actual 3D printer has to go through, start to finish, to build a 3D print job.

Stay tuned for more project pictures!