Rigid Tapping Trouble <resolved, wrong encoder>

[cnckeith]

right on! now lets see some video!

[suntravel]

old video, but same settings posted above, M3 with 2000 rpm



I never broke a tap with Centroid rigid tapping, nothing I could say with hand tapping

Uwe

[cncsnw]

I see you have Parameter 69 ("Duration for Min. Rigid Tapping RPM") set to 0.2 seconds. It was the 3.0 seconds value that was giving PFMDave trouble.

It would help if CNC12 provided a more meaningful error message -- preferably at parse time -- when the settings in Parameters 68, 69 and 82 combine to require a deceleration distance that exceeds the requested hole depth.

[PFM Dave]

Suntravel,

The video is very smooth. May I ask how you went about tuning the Rigid Tapping Configuration? Your setup is quite different than the "base" settings. CNCSNW provided some insight to how all the settings interact but your settings are well for lack of a better term all set very fast. I do realize these are set to each machine, mine is heavy and slow, yours appears to be lighter and well nimble. I guess what I am asking is did you trim these settings down say 10% at a shot until you had malfunctions or what procedure did you follow. By example I am sure my spindle decel time is well over .1 seconds.

Thanks in advance for your insight.

PFM Dave

[suntravel]

First thing is to setup the spindle drive to the fastest possible acceleration / deceleration. Maybe you will need an external brake chopper.
Second setting the gain parameters in the spindle drive to keep rpm stable under changing loads.

Then you can start to setup the CNC12 parameters for a faster rigid tapping.

Related reading:

https://www.centroidcnc.com/dealersuppo ... ds/304.pdf

Uwe

[cncsnw]

TB304 says that Parameter 37 is the time to decelerate from maximum speed to the speed in Parameter 68.
That is not correct.
Parameter 37 is the time to decelerate from maximum speed to zero speed.

I am also skeptical of the TB304 description of Parameter 241. Since it is described as a "rotational step size", and since Parameter 240 establishes the total length of the acceleration ramp, I have been let to believe P241 determines how many steps, of what size, are used to accelerate through the distance given by P240. TB304 implies that P241 determines the total acceleration distance.

[cnckeith]

TB304 says that Parameter 37 is the time to decelerate from maximum speed to the speed in Parameter 68.
That is not correct.
Parameter 37 is the time to decelerate from maximum speed to zero speed.

are you sure from max? sound like in the manual it is from programmed tapping speed?

[cnckeith]

1-28-25 i updated the Acorn Rigid Tapping Guide. TB304
https://www.centroidcnc.com/dealersuppo ... ds/304.pdf

[suntravel]

#37 is the time from tapping speed to 0, not from the max possible spindle speed.

Measured this with a sound spectrum analyzer while testing. Set to 0.2 = 0.2sec from 2000rpm tapping to 0

That needs to set up the spindle driver to 0.1s deceleration /1000rpm

Uwe

[cncsnw]

If P37 is the time to decelerate from the tapping RPM of any given tapping cycle, to zero, then that is a significant change from earlier software implementations.

That also implies that you would need to change the value in P37 every time you tapped holes using a different spindle RPM.

I suggest you ask a programmer who is familiar with the source code, to see what the implementation really is.

I do not think it is a good idea to require the operator to change P37 just because they are tapping with a different tool at a different RPM.