Erroneous Z axis emergency stops - how to fix?

[MarkU]

G0 moves (particularly up, but occasionally down as well) on my Taig DSLS3000 cause emergency stops (Mach3 software). Manually (via the Pg Up key) moving up at 100% speed also does this. It's worst at the top of the range, but has recently started becoming a problem at all heights. It's intermittent, but on a program with a series of slots etc it might happen every 5-10 minutes, and leaves the Z coordinates off by a couple of mm each time.

Replacing G00 Z10 with G01 Z10 F300 (mm) makes the problem go away but I would like to identify the problem and fix it. Brushed off and lubricated the ways & leadscrew, no obvious bits of junk stuck in there. I am mostly milling polycarbonate with a 1/16" cutter these days, so I am not straining the servos. No problems with X and Y.

Can anyone suggest what the problem is and how to fix it?

Thanks

Mark

[fretsman]

Hi, Mark,

I battled this when I first started up since my mill was in a garage and the temps could flucuate. This little adjustment fixed her right up but ingnore the fact that he says it's good from the factory as mine was not.

I also use the backlash compensation in Mach 3 to help with this as well.

Note, I only use backlash compensation for engraving as if you use this for larger work, it can actually "pull" the table into the cutter creating even more problems.

As found on nick carters website The Taig Lathe and Milling Machine

Adjusting the clamping shoe for the z-axis. The factor recommends that you squeeze it together with hand pressure then tighten the screws, without mounting the motor yet. This is usually fine from the factory so don't worry about it unless you need to. There used to be a screw from the front of the slide for adjustment but the factory found hand pressure was better for thsi adjustment.

[lsces]

What do you have the z axis motor speed set to MarkU? I found that Kurt's defaults were a little optimistic, and currently on the one machine here I have 1200 for Z and 1500 for X and Y
fretsman is right about things needing adjustment, and since the machines I see have been shipped across the Atlantic, I don't assume that they are 'fine from the factory' anyway. I'd only be happy with that if I was picking them up at the factory gate.
Even nowadays I'll load up a job that has run fine only the day before and I'll start getting faults, even though I do always run a 'wake-up cycle' to get the machine moving. But on the whole the machine is stable these days ... just need to make sure that the G1 speeds are low enough not to get the distortions at corners as mach3 starts moving the other axis before DSLS3000 has finished the previous move. Keeping a save height of 10mm ensures that G0 moves complete in free air