arduino mega + ramps 1.4

Hi, my name is gregory , i'm italian and i'm 18 years old.
i 'm trying to create a plotter xy . i have already created x and y axes using two tema 17 and work well. Now i have to create the z axis but i don't know how build it. is better to use a stepper motor with a trapezoidal screw or a servo motor without the screw? i have already bought an arduino mega and ramps 1.4 . i want only draw with a pen so which program is better? grbl don't support very well ramps 1.4 .
sorry for my english .

Take a look at this one, for example : [www.youmagine.com]

How do you generate the gcode for the pen plotter?
If you use "Inkscape" with a plugin to generate gcode ( there are many ) you can use Marlin as firmware. It works great with Arc moves.
I've used it with a laser engraver, it's the same thing.

You should use a stepper to lift the pen. Maybe just add a rubber wheel on the shaft that moves the pen up/down.

I changed idea , i can use a laser with marlinkimbra and inkscape , i have seen this module . [it.aliexpress.com] It can work well for cut paper or to write on wood?