Rigid Tapping Trouble <resolved, wrong encoder>

[cnckeith]

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.

yeah you are right that would be silly. it has to be spindle max speed to zero speed. checking on it now.

[cnckeith]

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

this whole TB needs a rework but this is acceptable and better than what we had!

[PFM Dave]

So,

I see this has turned into quite the post. I did fine tune the parameters a bit and it seems to be running quite well. In the future I will try to catch up with others tapping ant much higher RPMs and related feed rates.

Something I see on the new PDF that caught my eye was the Absolute position, on my machine it displays a negative number, yes the encoder is set to a negative -4000 pulses. In reading the new PDF I thought it mentioned a positive number, just saying not a must be situation.

Keith you asked for a video, was too large to upload so here is a youtube link. https://youtube.com/shorts/u2opF25hqw4

Again thanks to all who helped.

PFM Dave

[cncsnw]

"Abs Pos" is the raw encoder count. If your encoder counts negative during normal forward rotation, then you should expect to see a negative number there.

Presumed spindle position = Abs Pos / Parameter 34.

If both Abs Pos and Parameter 34 are negative, then the result is positive.

[cnckeith]

So,

I see this has turned into quite the post. I did fine tune the parameters a bit and it seems to be running quite well. In the future I will try to catch up with others tapping ant much higher RPMs and related feed rates.

Something I see on the new PDF that caught my eye was the Absolute position, on my machine it displays a negative number, yes the encoder is set to a negative -4000 pulses. In reading the new PDF I thought it mentioned a positive number, just saying not a must be situation.

Keith you asked for a video, was too large to upload so here is a youtube link. https://youtube.com/shorts/u2opF25hqw4

Again thanks to all who helped.

PFM Dave

thanks, youtube is the way to do (don't upload videos here we don't have the storage to host them)

video link is no good for me, please try again on the link would love to see it.

[PFM Dave]

Link should be free now

[cnckeith]

Link should be free now

success! cool isn't it?
nice. thanks for posting.

[PFM Dave]

Well yes and no... tapping .25 inch 60 -61 with a 6-32 tap had the tap break. To be honest I believe the hole had drill remnants in the tapping area. Turn 9n some air and try again...

Stay tuned..
PFM Dave

[suntravel]

Is the tap you used for closed-end holes?

Uwe

[PFM Dave]

No but it was a hand tap not a machine tap. In the previous holes it did as it should and tapped through the stock. Tapping a blind hole will be quite the challenge getting it to not bottom out and still tap to near bottom. I will fight that another day.

I will add in my air system for this tap routine to try and prevent this tap break.

Any insight on the difference between a machine tap vs hand tap would be good to know.

Any info on thread milling would also be great.

Thanks again,

PFM Dave