Implant .STL Won't Convert to GCode

[Roxy]

Of course opinions are going to vary. But I would do this in OpenScad.

height=30;
n_boxes_in_x=5;
n_boxes_in_y=7;
size_of_box=30;
wall_thickness=3;

cube([n_boxes_in_x*size_of_box+wall_thickness,n_boxes_in_y*size_of_box,wall_thickness]);

for(i=[0:n_boxes_in_x]) {
    translate([i*size_of_box,0,0]) cube([wall_thickness,n_boxes_in_y*size_of_box+wall_thickness,height]);
}

for(i=[0:n_boxes_in_y]) {
    translate([0,i*size_of_box,0]) cube([n_boxes_in_x*size_of_box+wall_thickness,wall_thickness,height]);
}

And guess what??? Its going to slice just fine because OpenScad doesn't have that bad behavior!