Hyundai Hit30s - Siemens 840C

[Web.eng]

G'day All,

Got a problem with a Hyundai Hit30s Lathe with a Siemens 840C control.
The machine had not been used for a while and when it was turned on again a week or so back, the memory backup battery was flat.
The tech guy apparently did a re-install of data from the machines own backup which got it up and running again but now it has an issue with thread cutting.
For some reason it seems to advance the pitch about 0.5mm each pass when thread cutting so instead of a single pitch thread you end up with a multi-pitch tapered looking thread.
Also, each time an M19 is cycled or the spindle orient button is pressed, the spindle orientate to a different position.
Anyone got any ideas?
Thanks.

Regards,
Dave.

[Tedger]

Dave
I have 2 Hit30's that run Siemans 840D. Both were bought used.When I went to for a pre-buy inspection on the older one(1999),I noticed that the switch on the spindle was replaced.Part# 6FX2001-8AA05 R6/B3126M.The shop foreman told me that they were having trouble with rigid tapping.I assume that since this switch sits atop a toothed reluctor ring,It must have something to do with position.Hope this info can help you.Also try siemans
https://support.automation.siemens.c...p6mcvepEO6rLYX
Ted

[Web.eng]

Thanks Ted,

The switch is working fine so I don't think that is a problem.
I have also noticed that the spindle does not seem to be running at the correct speed. For example I set the spindle running at 60 RPM and counted the revolutions while timing 60 seconds. the spindle only seems to be doing 50 RPM.
The machine was running fine before the battery issue.

Regards,
Dave.

[Tedger]

Dave
Is it possible some parameter was loaded wrong when the tech reloaded all the info? Maybe the spindle drive encoder? We don't have any good techs around here that I could ask,But I can check my parameters against yours if that would help.Let me know if there is anything I can do. Good Luck!
Ted

[Web.eng]

G'day Ted,

Yes, that was my guess, but to be honest, I don't know where to start looking.
Any advice appreciated though!

Regards,
Dave.