OK I think I am getting the picture, first off, on a large gantry machine (12'x8' and up table). It is usuall to have either an axis motor on either side of the x travel, or a shaft or means of a coupling from one side to the other or some method to keep both sides tracking parallel. check this out if the machine has it.
Most table are built with a compliant side and a non-compliant side, that is there is one side with something like a linear bearing as well as the rack to stop the gantry from moving sideways.
The first think I would do is to try and eliminate mechanical problem first, dis-engage the x axis drive (spur gear from the rack etc) and make sure the gantry moves by hand all the way along the track, while the axis is disconnected use the control to rotate the motor at different feed rates and check for erratic rotation etc. If all checks out ok , then I would perform an alignment of the drive, if it is a DC drive with tach feedback, I would perform the alignment by disconnecting the analogue input signal and provide a separate 0v to +-10 volts variable supply to the analogue input for alignment purposes, ( I have made myself a battery box with a 5k potentiometer and two 9v batteries).
This allows control of the x axis without the need for the CNC controller and tests the motor and drive amplifier.
If after all this you still have a problem, I would consider that there may be a problem with encoder or controller motor tuning parameter.
Al
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CNC, Mechatronics Integration and Machine Design.
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
Last edited by Al_The_Man; 09-12-2004 at 08:42 PM.
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