Hello, I am wanting to build a CNC machine that would have an X axis between 8-9 feet long and Y axis about 5 feet all to accommodate the 4x8 plywood. Has anyone had any success building one of this length or similar?
Considering that 4x8 is the largest standard size (5x10 and 5x12 goes into specialty territory), you would not need a wider cut than 4ft. Therefore, your X would be about 5ft and your Y would be 8-9ft. There are a few obstacles you would encounter. Rigidity: After a certain point, a 2020 extrusion is just not enough. It starts to become "stretched" at 1000mm. 1500mm requires multiple pieces, and even then is a hassle. Motion: Now your gantry is heavy. You need many more wheels to support the weight. But do you really want to stick with wheels? Why not linear rail? The more significant issue is your drivetrain. Forget belts. You may be able to get away with a 1/2" lead screw on a 1500mm length, but you'll need a bit more to span 9ft. This would go for both ball and lead screws. An alternative would be rack and pinion.
Biggest issue would be alignment of it all with something that large if you want any kind of accuracy.
