NS3DP - Non-Sucking 3D Printer

UPDATE!
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I am working on version 2:
https://www.thingiverse.com/thing:2999284

Motivation
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I am designing a new printer from scratch and I'm sharing it here so everyone can customize and build his own version of this. The idea is to make a printer with "big" build room without being "too huge" itself, and it needs to be fast, precise and affordable.

Plan
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The non-sucking 3D printer (NS3DP) is a cartesian printer with the bed moving in Z-direction and the print head moving in XY-direction. For the electronics, I chose the RAMPS 1.4 with the graphical display/SD module. It uses E3D Titan Extruders with pancake 13Ncm steppers for a lightweight print head. As much as possible will be 3D printed parts to keep the price low - as long as it doesn't affect print quality.

Details
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The frame is made of 40mm aluminium profiles. Optional diagonals can be used to make it even more sturdy if the build volume gets big.

I decided to use