Threading op (Lathe) - Stepper stuttering

[martyscncgarage]

Not quite sure what you need for the intercon program? I'm assuming what I have attached for that one is not what you need?

You didn't post the intercon file generated when you used CNC12 to create a threading cycle.

Marty

The file "conversational thread test v1.cnc" is the one generated from using CNC12 CAM to create the threading cycle. If there's an additional file from this somewhere other than the .cnc , I'm not aware of how to find it.

Intercon creates an ICN file that should be located in the c:\icn_lath directory
You uploaded the created G code file when you POST from Intercon

[cnc_smith]

Dan (brassmanwithaplan),

Looking at the 3 g-code programs you sent and your max rate of 50 inch per minute (IPM) on your machine that is where some of the problem is.
For threading take the RPM times the pitch of the thread that will give you the inches per minute the cross slide will be moving. PRM x pitch of thread = IPM

1) "conversational thread test v1.cnc" program generated by Intercon the RPM is 500 with a thread pitch of .125 so the inches per minute is 500 x.125 = 62.5 IPM. This is faster than you machine can travel so that is why the thread looked worst than the other 2 programs.

2) "1.4-20 UNC test 1.nc". The RPM is 500 and the pitch is .049213 This is 24.6 IPM

3) "rpm test.nc". The RPM is 250 and the pitch is .049213. This is 12.3 IPM.

In the parameters in the CNC12 you need to change Parameter 240 to 0.050 and parameter 241 60.0000. From the main screen F1 (Setup), F3 (Config), the password is 137 if you have the Wizard set for password required, F3 (Parms). Use the F8 key to page down to get to parameters 240 and to 241. After interning the above values press F10 to save and the ESC to go back to the main screen. If this does not correct the threading problem then someone that is more familiar with the setting for the steppers can help.

[brassmanwithaplan]

Dan (brassmanwithaplan),

Looking at the 3 g-code programs you sent and your max rate of 50 inch per minute (IPM) on your machine that is where some of the problem is.
For threading take the RPM times the pitch of the thread that will give you the inches per minute the cross slide will be moving. PRM x pitch of thread = IPM

1) "conversational thread test v1.cnc" program generated by Intercon the RPM is 500 with a thread pitch of .125 so the inches per minute is 500 x.125 = 62.5 IPM. This is faster than you machine can travel so that is why the thread looked worst than the other 2 programs.

2) "1.4-20 UNC test 1.nc". The RPM is 500 and the pitch is .049213 This is 24.6 IPM

3) "rpm test.nc". The RPM is 250 and the pitch is .049213. This is 12.3 IPM.

In the parameters in the CNC12 you need to change Parameter 240 to 0.050 and parameter 241 60.0000. From the main screen F1 (Setup), F3 (Config), the password is 137 if you have the Wizard set for password required, F3 (Parms). Use the F8 key to page down to get to parameters 240 and to 241. After interning the above values press F10 to save and the ESC to go back to the main screen. If this does not correct the threading problem then someone that is more familiar with the setting for the steppers can help.

I changed the parameters as you mentioned and saved them, then tried several of the tests cutting air. Unfortunately the problem persists.

I've also attached the correct files for the conversational threading.

Dan

[brassmanwithaplan]

Updated report as of today (Since parameter changes)

[martyscncgarage]

Can you please take a video and post it to youtube and SHARE a link here?

[brassmanwithaplan]

Can you please take a video and post it to youtube and SHARE a link here?

Here's a short clip, firstly showing the general jog movement, then I start a new program which I've also attached, with a finer thread and slower rpm.
It's mainly to show that it appears smooth yet hopefuly you can hear the difference between jogging and the program trying to run the thread.
I've reverted to using fusion as there is no difference between that and using conversational in CNC12, and I use fusion as my main output.



It causes a lot of juddery vibration and I'm concerned i'll cause damage to the stepper for instance.

-Dan.

[brassmanwithaplan]

Also, I have just updated to CNC12 v4.5 and tested the same program just on the off chance it was conflicting. Same result. no change or improvement (Not that I was expecting a magic fix!)

cnckeith will be happy I've updated

[martyscncgarage]

You aren't going to hurt the stepper!
Have you tried to do a thread yet?
Get a piece of PVC or Delrin and try it.
Post pictures of your results.

You seem to have a lot of lash in Z though that should be taken up ahead of the thread.
What kind of stepper drivers do you have? What is the motor voltage. What is the make and model number of the stepper motors?
I see you have steps/rev set at 1600, you might change the dipswitches on the stepper drivers and try at least 2000.
Also no limit switches no soft limits set.

Marty

[martyscncgarage]

You aren't going to hurt the stepper!
Have you tried to do a thread yet?
Get a piece of PVC or Delrin and try it.
Post pictures of your results.

You seem to have a lot of lash in Z though that should be taken up ahead of the thread.
What kind of stepper drivers do you have? What is the motor voltage. What is the make and model number of the stepper motors?
I see you have steps/rev set at 1600, you might change the dipswitches on the stepper drivers and try at least 2000.
Also no limit switches, no soft limits set. Though you just have to turn the diameter, measure etc.

Marty

[brassmanwithaplan]

You aren't going to hurt the stepper!
Have you tried to do a thread yet?
Get a piece of PVC or Delrin and try it.
Post pictures of your results.

You seem to have a lot of lash in Z though that should be taken up ahead of the thread.
What kind of stepper drivers do you have? What is the motor voltage. What is the make and model number of the stepper motors?
I see you have steps/rev set at 1600, you might change the dipswitches on the stepper drivers and try at least 2000.
Also no limit switches, no soft limits set. Though you just have to turn the diameter, measure etc.

Marty

NEMA 24 + M542T drivers,

Nothing fancy yet. I'd planned to convert on a budget then gradually exchange/upgrade parts as I go when the concept machine was sucessful for my needs (Which is is apart from threading)

The test cuts I made one that was good (It fit a threaded hole) although the finish wasn't great and the machine was still making the added vibration and juddery noises, but that could be other things.
One test created a double peak, i.e the timing of the thread start must has messed up somewhere.
And the other tests some of which stalled, although that is probably due to a high rpm mistake, so the stepper couldnt keep up with the acceleration etc.

I'll do a updated program and run some delrin or brass tomorrow and post the result, with program files and report.

-Dan