I 3D printed a 645 mask for my GX680. It's a remix of a 6x6 mask on thingiverse.
If interested you can find my files here,
I still might tweak it a bit more to make it easier to print. Some things are tight clearance wise.
I included the CAD drawing if you want to make further tweaks. Thanks to tbrun for posting the original CAD drawings, made doing the remix much easier.
If interested you can find my files here,
GX680 645 Mask by heliflier
I printed this with a .3mm nozzle and .15mm layer height and a .2mm nozzle and .1mm layer height. Both worked OK. If you over extrude, some of the cutouts will fill, these are easily cleaned up. Same with the first layer width. Some light sanding will help the slider move easier. I included the...
I still might tweak it a bit more to make it easier to print. Some things are tight clearance wise.
I included the CAD drawing if you want to make further tweaks. Thanks to tbrun for posting the original CAD drawings, made doing the remix much easier.