Remember Arc Lost position

[cncdrive]

Andrew,

I think we could save the arc lost position and make a function for the plugins and macros to read the 6-axis coordinates of the latest arc lost position.
I mean that the motion controller can register the arc lost position very precisely and make it available for the API and then we could make it available for the macros and the plugins.

However we currently working on the THC related outputs you asked for and the current g-code line highlighting on the toolpath which you guys asked about, will finish these first and will make a test release then...

[Robertspark]

Brilliant! I can see other uses for this such as an embroidery machine the runs out of thread.... cnc welder... etc

[Robertspark]

Yup, basically enable the thc, and toggle the arcOK... dros and line saved.

I would suggest some #vars... that way they can be called directly by macros or plugins... but I'll accept any solution really.

[shad]

Thank you Balazs!
It's will be very helpful, because this will solve big parts of the problems during cutting.

Also I think in this case we need one more future - Arc Lost delay (settable 0-5 second).
It often happens that an arc is lost on the end of cut, especially when overburn future used or when the cutter is turned off for a few milliseconds before cutting end for prevent divot forming. It's normal situation and CNC control does not have to stop XY motion.

Just when arc will lost, first - UCCNC has to catch current position, store position in the API and start ArcLostDelay timer. When delay time will ended, UCCNC stop XY motion.
I hope you understand me

Thank you!

[Robertspark]

When running overburn on sheetcam, can you not turn off thc at the same time as issuing m11 to turn off the plasma, and then continue the overburn.

I have my overburn set at 10mm for example (although deceleration has already started from 4500mm/sec), and I add a code snippet in 10mm before end of cut to issue an m11.

[beefy]

When running overburn on sheetcam, can you not turn off thc at the same time as issuing m11 to turn off the plasma, and then continue the overburn.

I have my overburn set at 10mm for example (although deceleration has already started from 4500mm/sec), and I add a code snippet in 10mm before end of cut to issue an m11.

Rob, that's pretty much along the lines of what I'd do too. I love the code snippets (and everything else in Sheetcam).

Of course this assumes the user has Sheetcam and for what it costs and the features it gives I can't understand why anyone doing plasma would not buy Sheetcam. I couldn't live without it.

Andrew,
I'm all for new useful features but if the same thing can be achieved in cam software like Sheetcam, should we be asking Cncdrive to try and do it in UCcnc ?? Apologies if I'm misunderstanding what you are asking for.

Keith.

[Robertspark]

Andrew, the only negative I see with the neuron is that you've only got one digital input which is the thc on/off.

Given the torch on/off is Ethernet controller, there is some latency there, hence your overburn is likely to be slightly inconsistent (we are obviously talking milliseconds here)

For the feature you asked for, you will need a cam software with overburn built in. I do not profess to know all cam software, but without overburn in cam that function is going to be limited in use is it not?
Hence you should be using a snippet (or whatever other cam software calls it) to I sent the THCOff and m11 which ignores the arc Ok signal and continues the motion as required.

Does anyone have any recommendations of what overburn they run and why? Do you go to the point of calculating your deceleration distance from say 60% feedrate and that is the optimum overburn (too technical, law of diminishing returns??)

[shad]

Rob, Keith, you do not understand me.
I mean, to add delay between two events: UCCNC will have arc lost signal and then Feedhold (or stop) of the XY motion (because ArcOK signal will be lost). I hope you understand me if you have many time of the Cut.
This task only for UCCNC. Not for CAM.
I am talk about regular THC like Proma.
If we talk about the Neuron - now I have 10 msec for send Torch ON/OFF and ArcOK command to/from the controller. To be honest it's less then denounce time for hardware IO. And it' works fine.

[beefy]

It often happens that an arc is lost on the end of cut, especially when overburn future used or when the cutter is turned off for a few milliseconds before cutting end for prevent divot forming. It's normal situation and CNC control does not have to stop XY motion.

Just when arc will lost, first - UCCNC has to catch current position, store position in the API and start ArcLostDelay timer. When delay time will ended, UCCNC stop XY motion.

Hi Andrew,

I'm guessing I'm not fully understanding what it is you want to achieve.

When you say, "arc is lost on the end of cut", do you mean accidentally or deliberately.

Example for divot prevention you turn off the torch (deliberately) a short distance during before the cut path ends. Therefore you are turning off the torch DURING motion and you do not want the loss of Arc OK to stop motion. That is completely achievable with cam by inserting M206 (THC Off) just before the torch is turned off. Then any THC Up/Down signals are ignored and loss of Arc OK will not stop motion.

The same with an overburn situation, this is a deliberate action, and you can put M206 in the code just before the overburn path starts.

Are there also any non-deliberate situations you are thinking of ??

As for stopping XY motion, because you are talking about the end of a cut, the motion will stop regardless (at the end of the cut path). So yes, I'm confused why you would need UCcnc to stop motion when this ArcLostDelay timer has timed out.

Also, because you are talking about the end of a cut I am confused why you would want to catch the current position.

Keith

[Robertspark]

Example for divot prevention you turn off the torch (deliberately) a short distance during before the cut path ends. Therefore you are turning off the torch DURING motion and you do not want the loss of Arc OK to stop motion. That is completely achievable with cam by inserting M206 (THC Off)

+M11 (provided you fired the plasma with M3 M10)

just before the torch is turned off. Then any THC Up/Down signals are ignored and loss of Arc OK will not stop motion.

...no I am not getting it either .... The Proma will work with that combination above too (although the proma is very slow!!! .... I need to sell my old one...!)

I only know of sheetcam for plasma, I don't know if / how well cambam does plasma or any other small user plasma software (read: not expensive).