Bridgeport Manual to CNC conversion...

[Davek0974]

Ok, what sort of acceleration should i be aiming for if i have a top speed of 3500mm/min and bearing in mind this is a Bridgeport with a fairly heavy table;)

[JAZZCNC]

Ok, what sort of acceleration should i be aiming for if i have a top speed of 3500mm/min and bearing in mind this is a Bridgeport with a fairly heavy table;)

I'd up it until starts stalling motors then back it off 25%. 750s/s would be nice figure to aim for.

[Davek0974]

Ok, i'll try upping it but it would not stall - it has some fairly big AC servo's on it and a 2:1 reduction so damage would occur first i think or drive shut-down maybe.

[JAZZCNC]

Ok forgot you have servos But same applies really however instead of stalling you'll get position errors or drive trips.! . . . You'll know if OTT

[Davek0974]

Ok I'll dive in tomorrow night, thats the thing with servo's - you have to set an acceleration and top speed then tune the servo drive, it takes a fair bit of time to do each axis.

[Boyan Silyavski]

But left side corners are undercut and right side corners are overcut, from what i see. So i dont think its the acceleration. What does that tell? To me- mechanical play.

[Davek0974]

no, the corners are "dog-boned" or "T-boned" to get a square object in there.

maximum play is 0.04mm on any axis.

[Davek0974]

Instant improvement, same code as before, same feeds etc just the increased acceleration in motor tuning.

Nice corners, no sign of rounding at all.

At least it now works up to 1000mm/min feed rates, no idea how much beyond that as i have no job that needs it.

[JAZZCNC]

But left side corners are undercut and right side corners are overcut, from what i see. So i dont think its the acceleration. What does that tell? To me- mechanical play.

That tells me you know nothing.! . .

[AndyGuid]

Cutter was 2mm at 23000rpm, 1000mm/min, X&Y speed set at 3500mm/min and 350mm/s/s in motor tuning.
Attachment 19724

Instant improvement, same code as before, same feeds etc just the increased acceleration in motor tuning.
Nice corners, no sign of rounding at all.
At least it now works up to 1000mm/min feed rates, no idea how much beyond that as i have no job that needs it.

Just to clarify please, that the only difference between the Before and After results above was an increase in acceleration in motor tuning?

That's quite amazing!

P.S. Apologies that the first damn image (Attachment 19724) keeps appearing and then disappearing from automatic display!!!