This week we take a slight change of pace, and we do some work with the 3D printer, and how it works, and design for it (this is also a lesson in what to do when the IT goes wrong…).
I switched it this week as one of our club members is going on holiday at the end of the standard 12 weeks we run, and I bring in my 3D printer and run some additional lessons after for some who want to continue. As this member would have missed the 3D printer session (and I have spoken to there parents about him wanting one) I thought I would switch it so they didn’t miss out.
I also found that week eight was a particularly tough bit of coding, and we’d hit a wall – so a break with a bit of fun would refresh them for week 10.
We cover in this lesson:
- How a 3D printer works
- How we design items for a 3D Printer
- How the computer turns 3D models into instructions for a 3D Printer
First thing we go over is how the 3D Printer works and safety around the 3D printer. The type of 3D printer we were using is a FDM (Fused Deposition Modelling) which is the most common, where layers of plastic are extruded through a nozzle and layer upon layer is added to the model to build it front the ground up.
We see whilst its running how the printer isn’t printing solid and how it prints a structure inside (like a beehive) to make it rigid and strong without using lots of material.
I show them the materials that the printer uses, and then how the printer pulls it in, melts it and essentially “draws” each layer onto the bed. We definitely go over safety, as this is running at 210 Degrees C when printing.
When it comes to design, we use TINKERCAD. this is a free to use web based 3D modelling software. It works with primitives (basic geometric shapes, cubes, cylinders etc) to allow the user to build models. They can change sizes and dimensions, merge shapes and also cut from shapes to create new models). What is also good is it is provided by Autodesk, and the account they class make also work on Fusion 360 etc if they progress down that path.
We go over the basics of design (and we do keep it basic) in how to modify the dimensions of a shape, how to rotate, move and change.
We then show how to merge shapes, and cut one shape from another.
The main thing I find the classes always struggle with is moving the pieces in 3 dimensional space. This happened every year! So its good to let me get used to moving items around in 3D.
I let them design what they wish, but talk to them about how to design so its easy/possible to 3D print. I show them how the 3D printer works and how overhanging elements – e.g. a model of a person with an arm sticking out – makes it hard to print.
I show them how the 3D model in the screen gets turned into instructions and how these are mapping a path from point A (the lowest point on the model) to point Z (the highest point on the model) and how each instruction shows the nozzle where to move and how much plastic to put down. It is like the LOGO turtle, but with a million times more precise instructions.
Now this week we had some issues, as the libraries internet was playing up and we had to double up on the machines so not everyone got to design what they wanted there and then however I provided the parents with the details, and they all can have a go at home and bring in their models next week, which is the beauty of using something web based and free like TINKERCAD.
This is one of my favourite lessons as it never fails to grab the attention of the class, and I sometimes forget how lucky I am to have 2 3D printers in my home, and how this is common place to me. Often, when I speak to the class and their parents its very sporadic levels of computing in the schools they attend, or the schools have the equipment but not the time or resources to allow them to be used to their potential. This class allows the children to have access and see something up close, and have something printed out that they have made to take home and enjoy, and the ability to take something virtual and make it tangible really sparks their imagination.