A43D new H-Bots 3D printer

Hi,
i need a more bigger printing surface than my solidoodle.
So i decide to make a H-Bots who have A4 format for printing surface
(21cm/29cm)
So i naming this A43D.
Download all file in the same directory, open "Imprimante.scad" (printer in French) or other part.
you can test some mod with "Parametres.scad"
It is my first project with openscad, so, i don't know all possibility.
If you have some sugestion, your welcome.