3D-Printing consists in melting plastic at ~200°C inside the extruder (PLA, ABS, PETG, and many more but I strongly recommend PLA) :
Here you can see that the glass under the object is warmed up at 60°C. The extruder is at 200°C inside and it's isolated from outside so it only shows 82.2°C (in white above the object).
The extruder is moved on X axis, while the object moves on the Y axis (on this particular machine called RepRap Prusa i3 reWork) to deposit the melted plastic layer by layer, starting from the glass at 0.2mm per layer with a 0.3mm extruder diameter. This is customizable : extruders are from 0.1mm to 1mm, layer height must be between 0.1mm to ~0.85mm, so YES precision is important, but quite easy to achieve in fact, with patience and good components.
When each layer is completed, the extruder is raised on Z axis, by the "layer height" amount of mm.
I have two powerfull wind turbines blowing fresh air on the object, which I started to use right from the start by instinct : two fixed and powerfull fans are better than having a small fan on the extruder itself adding weight on a mobile (and important) part: the extruder.
I saw my first RepRap in Paris at the /tmp/lab then I built mine at the end of 2012. Starting exactly in January 2013 to 3D-print on my own "RepRap Mendel".
Then I upgraded, a unique thing with this hardware, to a new version : the RepRap Prusa i3 ReWork from the french company Emotion-tech who I know from the begining of their adventure ! Thanks to them for their support.
You can find more informations all around Internet like :
Wikipedia Definition of 3D-Printing
There's a lot of websites about it. See the /LINKS page.
Here a last example of a Pan-Tilt machine I made in 2016 for a party organizator, it can carry 2,5Kg of hardware oriented on 2 axis, controlled by a simple arduino Uno and a motor shield.
