Our 3D printer is basically just a smart glue gun that uses a computer to carefully drool melted plastic in very precise layers. 
Ours started out as a big box of 3D printed pieces, bolts and motors and assorted parts (and two bags of Gummy Bears!) and was built over the Holidays last year. If you want to sound really nerdy…The technology it uses to build 3D prints is called Fused Deposition Modelling and takes a string of plastic filament, heats it up and squeezes it through a tiny hole called an extruder…here’s the one from our printer.  Notice the big fan on the front to cool the melted filament as it comes out and the white sensor that tells the printer how far from the bed (the heated square plate that whatever you’re printing is printed on).

The extruder is attached to a moving head that lays down layer after layer of the plastic, slowly building the 3D model it’s been given on an SD card or straight from the USB port of a connected computer.

Here it is having printed the Dragon I brought in to show you…of course ours was printed in silver filament and was MUCH cooler! 😉

3d print Flexi Rexi…great simple print that shows how to print one part that has hinges and can move!

Printing Basics

First SAFETY!

Don’t touch the printer while it’s moving…you can get your fingers caught…I’ve done it and it hurt…both me AND the printer!

Don’t touch the nozzle…that sucker is HOT enough to melt plastic…and BBQ your fingers!

PRINTING ON THE PRUSA

Find and download what you want to print…you’re looking for .STL files…of which you’ll find many at Thingiverse.com

Import the .STL file into PRUSA Control software…it’s icon is an orange 3d printer… printing a dragon.

Set the various print options…

MATERIAL

There are all sorts of different types of printer filament (printers use ink 3d printers use filament…it’s like a long strand of glue from a hot glue gun)…but we’re sticking with PLA because it’s cheap and it doesn’t smell horrible when we print it!

AllThat3d.com has a great page on all the different filments and what they’re best for if you want more info…there are some really neat ones too!

INFILL

Infill density is just how much support your print needs…have a look at this…the more you use the longer the print takes…so think about what the best balance for your print is going to be.

BRIM

See the puddle around the octopus’ arms below?…that’s a brim or sidewalk…and it just prints extra material to make sure that the actual print sticks to the printing plate properly and doesn’t pop up and screw up your print.

SUPPORT

A frozen Minion?!…Nope!  A Model with overhanging parts that need supports

Remember that the 3d Printer just spits out melted plastic…if you don’t have supports it’ll just droop or drop!  Supports are 3d printed scaffolding for any overhanging parts like minion’s arms and fingers and his goggles that stick out from his face.  Don’t leave them hanging! Make sure you click on supports if you’ve got any parts that aren’t supported by the rest of the model.

Support can be from the print plate…like the minions arms and fingers and from the model itself…like parts of his goggles and the strap around his head.