Lost steps in Z on a 15L?

Lathe
1

It’s been a few months since I last used my 15L and I am now finding that steps get lost while rapiding in Z, especially in the last 60% of travel. I’m using Mobil Vactra #2 in the auto lubricator and have cycled lube several times over the course of a week as well as manually applied lube to the way wipers with the spindle off but am still seeing the problem with lost steps. I use flood coolant so it’s possible that enough of that has evaporated on sliding surfaces or ball nuts/screws to cause excess friction.

Does anyone have a suggestion on how to resolve the situation?

2

Check (and mark) the coupling to the Z motor to be sure it’s not slipping?

3

And wiggle your motor electrical connections.

4

Thanks - I’ll check the motor coupling and wire connections, but suspect there is gunk on the ball screw or ball nut.

5

Well, the wire connections all seem OK, the Z-axis ball screw looks very clean, and the ways and ball screws seem to be well lubricated so I think that none of those three items are issues. I’m now wondering if the Z-axis drive may be at fault. No steps get lost so long as Z is not moved too fast, say 45 ipm, so I’m just letting things alone pending new info or problems.

BTW, I couldn’t inspect the Z-axis stepper coupling as the enclosure prevents ready access to its cover.

6

I ended up replacing both the X and Z axis drive belts on my 15L they had become stretched

7

My belts seemed to be reasonably tight still. It sounds like the Z stepper is running free when it starts to lose steps; that’s why I’m thinking there may be a problem with the drive unit.

8

Gotta pull the cover. Forget which pulley, but there are 3 or 4 socket head cap screws, those tighten a set of cone washers that engage the shaft. Gently see if they are snug. I believe they provide some measure of safety for crashes so not too tight. The other thing is you can adjust rapid speeds in the admin. I set mine to max and had problems too. Doesn’t like it. Find the max by trial and error, reduce a little. Not really worth the half second you might save. Tough on the machine especially if your moving heavy ass turret.