You have a nice looking machine; you did lots of work to get where you are!
Whose machine control software are you using?
Whose drivers do you have for your stepper motors? How many volts DC does it use?
Is that single side drive? It looks like there is only one long axis drive.
Does the machine run smoothly when the drives are disengaged and you move it left-right and forward-back by hand?
There are lots of factors involved in a smooth operating machine.