Hi,
I'm thinking about building a 3D milling machine from scratch. It hasn't got to the serious plan stage yet (and probably won't for a year or so for various reasons), just the figuring-out-how-to-do-things-well stage.
For a metal milling machine, everyone says structural stiffness is the biggest difficulty of home-made machines, which I get. So my question is, why does everyone (seem to) build gantry-style machines?
It looks to me like it'd be much easier to build a frame that supports the Y carriage from the top - that way the gantry frame doesn't form a big lever to apply a torque around the X carriage bearings. It's a bit hard to explain what I mean - I'm thinking of a structure something like this:
Obviously it's going to weigh a lot more and cost more to construct than a gantry, but also be much, much stiffer. At a rough guess, I'd manufacture it from 50mm square tube. Maybe having access to a power saw, MiG welder etc is an advantage I have over others!
Thoughts?
Tom