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Y axis screw is jumping. Maybe about 0.002-0.003". Worse in one direction, and "appears" to be more prevalent in one location. But may be along the length of the travel. It jumps about every 1/2". Perhaps each screw revolution?
Is this likely:
1. a bad spot on the screw, or
2, a bad ball in the nut circuit, or the nut itself, or
3. a bad spot in the thrust bearing?
clay
I dont know but heres my logic:Quote:
Originally Posted by claya
probably not a bad spot on the screw since it happens every 1/2"
if you know your ball screw pitch you can figure out if its possible that its a bad spot on the thrust bearing or not by using the "happens every 1/2 inch" and the pitch of the screw, and seeing if that lines up or not..i.e. if your ballscrew turns 3 times for every 1/2" and you only see the problem once in that 3 times, then its probably not a bad spot on the thrust bearing
how did you notice this was happening?
Hi,
I also think the screw is very unlikely to cause the problem - any damage there should be easily visible and only affekt a small area.
Loosen the nut from the rest of the machine so you can rotate it freely by hand without rotating the screw. If it still jumps it is the nut - if not it is the bearing.
Christian
There is a distinctive "circle" where the end mill dwells, and then jumps. You can not only see the effect in the cut, but feel the lag & jump during most of the y-axis travel range. I just happens to be worse in a 1-2" area of the travel. Right where the vise range is.
The screw pitch is 0.4. And it looks like the dwell jumps are also 0.4 apart. Methinks it is the screw now.
Quote:
Originally Posted by acannell
I would bet it's the screw alignment to the axis or a bent screw. It could also be the bearings at one end or the other or the attachment between the motor and screw.
Ben