I'm faced with a lot of options on this one, and simply trying to decide which route to go. Here's the problem and what I have to work with:
It's a 90's model 5' x 10' industrial duty plasma table made by Advance / Koike up in NY. It has a beefy steel gantry with steel guide tracks and drive on one side, and a non-guided support roller on the opposite side. I stripped off the old analog servo motors and replaced them with some 1150 ozin nema 42 steppers I already had. It was very easy to convert - a new motor plate for each one, and I reused the 3 to 1 timing belt reductions and rack and pinion drive. These motors will reliably do 1500 ipm on the X (more on Y) at a good acceleration rate. The problem is it's a rather heavy gantry and the further the torch carriage is from the drive side the worse the deflection is from acceleration. I've backed the acceleration way down and can make good parts on the drive side of the table, but really need to tie the other side in so I can put the acceleration back up where it should be.
So, here are the strategies I've been contemplating:
1. Add another motor and drive the far side. I think the most logical thing here would be to take the motor and drive I'm using on the Y off since it matches the other X and use it. I could then use a smaller motor on the Y since it weighs nothing compared to the whole gantry. That would give me a perfect match for the other end of the X. Obstacles - finding matching rack gear (not sure what the specs are for the stuff they used - it's cut from bigger stock than usual for it pitch), having to rigidly guide the opposite side (potential for binding?), and having to rebuild the Y
2. Add a crossshaft at both ends of the table and add some long timing belts. I'm thought of 2 scenarios here:
A. Simply add the crossshafts and belts to tie both sides together but leave the rack and pinion drive alone. The belts would merely hold it square and not actually drive it. This would be a fast, simple modification!
B. Ditch the rack and pinion and connect the motor via 3 to 1 reduction to the crossshaft. This would be a little more involved than A
I've also considered lightning up the gantry with some serious hole saw work. It's ridiculously overbuilt and could get some swiss cheese action without compromising it's strength. Also, I should point out that when it's locked stationary with the motors it takes a LOT of force on the far side to manually deflect it. So I'm really only fighting the springyness of the beam and not backlash or bearing slop. This is why I've been leaning towards option 2A - the simplest.
How would you fix this problem?