Spindle PID setup

[Robertspark]

I have swapped out my spindle motor on a denford Orac lathe for a 750W AC servo with drive from ASDA

I was looking for a servo that matched roughly the AC motor that was being swapped out and also was of a similar frame size so that it could be fettled to fit the mounted bracket / holes of of the old motor being replaced which was a 1/2HP (0.37kW)
https://www.deltaacdrives.com/wp-conten ... Manual.pdf

I was looking for a servo drive I could just feed with 230V single phase and didn't need another power supply for, hence the ADSA-A2 was what I needed / wanted.

I came up lucky on one on ebay being sold complete never used with a sundry breakout board and all the associated wiring etc that has helped at the same time I was looking.

It is HTD 5M belt driven with a 2:1 ratio as the original motor had a listed spindle speed of 2000 rpm which I didn't want to exceed. (I could not see how they achieved that speed though from the old drive with the pulley ratio the old motor was running but who am I to question)
The servo is rated at 3000rpm and has a maximum speed of 5000rpm.

I used a couple of tapelock bushes for the tapelock HTD pulleys as I could get one to match the spindle size of the lathe to replace the old ribbed belt.

I've since added a hollowshaft spindle encoder to the lathe spindle to replace the optical index as I found one as a cheap option that fitted over the spindle.
One of these but with I think 1000ppr / 500ppr (I forget).

guess you've been through the denford forum for all the technical info: http://denfordata.com/bb//viewforum.php?f=33

[drumsticksplinter]

Hi Robertspark,

Thanks for your advice on the servo and drives. This is definitely something I will consider in the future, but I think for now I need to make the best of what I have and actually start using the machine.I fear if I take on another element to retrofit, the machine will just be in a pile of parts and cables again, as it has for the last 2 years or so

There doesn't actually seem anything wrong with the DC drive, just a question of how reliable it will be for rigid tapping, something I need to test before I discard the old control and motor. I have now got it wired to reverse, it just uses a relay to switch over the contacts, this was original to its wiring from Denford, I have just added another relay to make UCCNC easier to activate the spindle go relay and the reverse relay simultaneously to get reverse, bit of a strange way of doing it, but it works. I did actually do a retrofit of a Bridgeport MDI a few years back, which originally used only a single servo drive between 3 motors, by means of relays it just connected the relevant motor to the drive to move each axis in turn. I guess servo drives were more expensive back when it was built...

[drumsticksplinter]

Has anyone got any pointers for the tapping cycle in UCCNC please?

I'm using Fusion 360 and the latest UCCNC post processor, which outputs this for my tapping cycle:

Code: Select all

M5
(Move to tool change position)
G53 X0. Y0.
M0 (Pause program for tool change)
T2 M6 (right hand tap D=5.)
S500 M3
G61
G54
M8
G43 H2
G0 X25. Y-25.
Z45.
Z35.
G33.1 Z0. K0.8
G80
Z45.
M9
M5
G53 Z0.
M30

However, it gets to the line G33.1 Z0. K0.8, spindle running CW and just stays there, its like its waiting for the spindle index to start tapping. I have my spindle encoder setup and PID tuned (mostly). Does UCCNC look for the encoder index pulse, or does it just read the A,B pulses?

Thanks,

[dezsoe]

Yes, it needs the index, A and B signals.

[drumsticksplinter]

Ahhh, I'll double check this then. I hadn't paid too much attention to the index pulse as I thought I'd read it was unsupported with the spindle encoder? Perhaps I have a setting wrong maybe, will check Thanks