I have the FLA100 kit from
Store: FLA100-00 : Fine Line Automation
The x-axis seems to get some whipping with the screw rod. Not sure what I did wrong and how to stop it. I would appreciate any help on this problem.
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I looked at the design a little bit. It appears although there are thrust bearings near the stepper motor, the other end is left floating. It is a rather simplistic, low-cost design, which is what it was intended to be, but not a good design in my opinion for the length of travel.
It could be improved by using an angular contact bearing at the floating end support (or another thrust bearing on the outside but it doesn't look as if there is a radial bearing in the end support block), and belleville disc spring washer(s) (stacking more than one in convex/concave arrangement would give more force when they are flattened), and two nuts (one to pull on the screw and compress the disc spring washer, and one to lock the other in place) on the very end. This would "stretch" the screw (not really stretch, but put it in tension) and inhibit the whipping.
It could also just be that things are not in allignment, inducing the whip.