I saw an idea a while back, that might work for you. Gary is right about stiffness being important, so here's an idea for keeping down the price.
A garage or shop already has 6 surfaces (4 walls, ceiling, floor) which are built to be reasonably rigid. Attaching to those walls and ceiling might be an appropriate option.
I had my own idea, a while back, about using garage door parts (rails, drive screw, etc) to build a really big router which would hang from the ceiling. Since they're built to be linear motion components already (and can be beefed up and made of higher quality with relative ease) this should be a workable solution. By having an opening on both ends of your shop, you can have an "infinite" X axis length. Since your gantry would be hanging, you could build it as a truss for stiffness, but relatively light weight.
This should be a workable solution for you, and Z axis travel would be limited by the length of your rails, rather than the clearance available...the floor would be the absolute limit, obviously. Placing panels on "sawhorses," or some other type of support could be a workable solution, to raise it to whatever height you require.
What type of resolution do you require, and what level of accuracy? Are we talking about .001" or 1/8" accuracy? That will determine the cost of the required components.
-- Chuck Knight  |