If you use slaved servos, cross connect the following error outputs to the other drive's error input. If they get too much out of sync they could easily pull your machine out of alignment. I've thought of using slaved servos myself, and would make a supervisory circuit that would disable the drives if they get out of synchronization. If you aim for a decent acceleration, the forces of these motors acting asynchronously will be quite large.
Another solution might be to make a deliberate weakened connection of the gantry to the pads driven by the spindles. Like a mechanical fuse that will let go if the forces is above a certain point.
How do you do when milling in the center of a queue, will there be a following steady on the lathe slide to support it?
In your first drawing the slides looked like rods only supported at the ends, but the last drawing show them connected to the base structure along the full length. |