Hello,
I've spent some money so I guess I'm into it now.
Intro: I'm a recent mechanical engineering grad, which probably means I don't know anything AND I'm too cocky to admit it. I learned a lot about machine design in college but there's no substitute for experience...that much I've learned from experience.
Anyway, the plans:
- Welded steel frame, 2"x2"x1/8" tube
- Linear profiled rails/bearings
- Double ball screws on the X
- Nema 23s
Main goals:
- Frame rigidity, minimized vibration and flex
- Accuracy / repeatability
- Long z-axis travel
Not as important:
- Anything happening soon... it will still take me a long time before I see any woodchips flying
- Cutting speed
- Precision / resolution. I'm carving wood, not etching a circuit board.
- Cost. If (when) I run out of money, I'll slow down, save up, and get back to it when I can
Main questions:
- How perfect do my rails have to be for the bearings to slide easily/properly?
- - My plan is to have the X axis rail beds machined both at once at a local machine shop. It took me a while to find, but there's a shop nearby that has the capability to cut 3' x 4' in a single setup.
- - Is this necessary? Or can I just cut the rail beds on a manual mill one at a time?
- Are there disadvantages to having the Y axis rails on top of / underneath the gantry instead of on the front? Most machines have them on the front.
- - I put them on the top and bottom to keep the Z axis closer to the gantry...didn't want it sticking out farther than it had to.
- - I can machine both Y axis rail beds at the same time on a standard manual mill so they will be perfect relative to each other
- Are my gantry ends strong enough?
- - It's 1/4" plate right now...both the horizontal plates and the vertical ones
- - I have some 3/8" plate if it's worth the added weight
If there's anything else that seems inadequate or poorly designed, let me know!
Thanks