Wanted to post my basic design for a moving gantry mill/router that I'm planning on building over the next year or so.
Base/mill table is a 36x64x6" granite surface plate, linears are 35mm NSK's and the spindle is a 120 lb, 16 HP (I'll need to derate for single phase) Colombo with 7 ft-lbs torque. Projected work envelope is 41x19.5x~14.
Other materials are 6", .25" wall square tubing, .5" and 1" plate. Other than the granite, spindle and linears I'm completely open to using different materials, those are just what's available at reasonable prices around here.
Haven't put too much into linear motion control yet. Probably do ball screws for gantry and Z and end up with R&P for the long axis.
Primarily plan to cut aluminum, but other nonferous, composite and plastics will see time on the machine as well. Would be able to do light steel work occasionally. This won't likely be a production machine, more for prototyping and short runs of my designs.
I've already got the spindle and am planning on picking up the surface plate soon, the linears are automationoverstock and seem like a steal, so I'd like to stick with them. The rest of the design is wide open. Plan to weld the 2 6" square tubes together and weld on the 1/2" strips for the rails to sit on. Will probably need to do epoxy leveling for the gantry as I don't have any other way to make them flat (and I can use the base as a reference surface.) The rest I plan on using a zillion bolts to hold together, so I can modify the design easily later on.
Fabrication of the plates will be some multi-setup work on my CNC converted RF30. (about 7x18 travels.)
Rails will be held to the surface plate by core drilling and epoxying in threaded inserts. Work holding will be similar. Right now the plan is to get some 4140 prehard rod, core drill 1" holes on a 4x4" grid (with a small drain hole at the bottom of each) epoxy in the rod, then drill/mill in place 5/8" dowel pin holes on top of thread milled 1/2"-13's.
Thoughts? Any glaring issues? I haven't done any simulations yet, but will, and I'm sure some of the design will change when I do.