THC always hits THC Velocity Lock

Great to get you going.

You need to determine the maximum velocity your motor is capable of without loosing steps

You then need to determine the maximum accelleration your motor is capable of without loosing steps. I have found this is much more critical. It is when accelerating that the load is on the motor. When you get to speed, the load falls to about 30% of that used when accellerating (motor/driver dependent).

You need to test this in the real world as I found simple oscillating back and forth does not test it out.
I also found that when a motor gets hot, that is the time that it will start to loose steps.

You also need to heed the comments here and adjust

Thankyou - watching my Z axis stepper go back and forth during cutting is a thing of BEAUTY.
Now that everything is 'basically working' we'll tune and tweak it. Since my duty cycle is only one part at a time - pushing temp. on motors or drivers is not an issue. That said the dynamics is very important for 'accurate' parts, corners, etc. Nice catch on the STEP GEN values. Thanks.

Hi, I read many many post to setup my baby-cnc-plasma (thank you all! Great help!.
(Sorry to write here but it's the same problem as the first author, so I thought not to open a new thread.)

After setting up many things on a completely diy cnc machine, after cutting some test part, I'm now trying to cut some actual parts for a project and I have the same problems of THC blocked. (I swapped to shielded nozzles and the shield is critically near the metal to respect the cutting height... so I want the THC to work well.. I don't want to brake the new 400 USD torch for crashing into the metal... )

I read all this thread: I have a "max speed" in LinuxCNC config panel of 1999 and I was trying to cut at 2200 (2mm thick part), so I increased the MAX_VELOCITY X and Y in the .ini in my config dir and I reopened LinuxCNC, but the "max speed" parameter in the config panel has not changed.

I saw there are 2 MAX_VELOCITY parameters for every axis...

So my question is: which of the two MAX_VELOCITY (the first one or the second one) do I have to increase? and in which file? I changed these in my plasmac_06.ini (plasmac_06 machine) but it seems it's not changing the "max speed".

The .ini file was generated by the pncconf (than I used the python for installing plasmaC) I use a 7i96 and a THCAD-10.

Thank you for the reply,
Alberto.

jazzkramer wrote:

I read all this thread: I have a "max speed" in LinuxCNC config panel of 1999 and I was trying to cut at 2200 (2mm thick part), so I increased the MAX_VELOCITY X and Y in the .ini in my config dir and I reopened LinuxCNC, but the "max speed" parameter in the config panel has not changed.

Max_setup_speed is for the Z axis only, how fast it can move during the fast probing section and while correcting during cuts.

jazzkramer wrote:

I saw there are 2 MAX_VELOCITY parameters for every axis...

Both, for each axis and joint. Just beware the AXIS stuff must be twice the JOINT stuff for plasma.

Thank you very much tommylight for the explication
Tomorrow I will change both (paying attention to the AXIS stuff must be twice the JOINT )
and test again
Thanks,
Alberto.

I tried, it works, thanks, ...even if now I have another problem and new doubts. I will search the forum and open a new thread if I don't find an an answer.