Cut Parameters

rodw wrote:

tommylight wrote:

On big machines with more amps and cutting thicker materials it would be nice to switch the torch off just before the end of the cut as that would lessen the divot made by the start and the end of the arc at the same place.

To me that does not make sense. With thick material, the lower side kerf can trail behind the top side by 5mm. I thought the torch off delay (or an overcut) was to allow the lower side to catch up to the end point which implies it should still be at cut height.

For cutting mild steel, the kerf will have to be about 5 to 15 degrees before the torch, not behind. That messed up with mu head when i first found out, but it proved to be very real. Then again, i cut under 10mm, so Stefan might be a much better source of info on that.
Most of the other materials will lag behind, but for mild steel i am very certain it has be be in front of the torch, that is when you get clean cuts with very little or no slag.

OK, at this stage I am leaning towards:

Remove "Torch Off Delay" completely from PlasmaC. From what I have read, using this parameter is only going to increase the size of "dings". Basically when you tell the torch to turn off you really want it off now. Plus it seems that air plasma already has a very short afterburn that varies from machine to machine.

"Pause At End Of Cut" seems like it may be a good parameter to add to "Cut Parameters". Basically the torch turns off and motion pauses for the "Pause At End Of Cut" time, then the Z axis rises to the "Safe Height". It would also be easy enough to add this into the GCode parser so that it is automatically applied if it is set in the current material. This then makes it easy for hand coders or guys using CAM that doesn't support it. If the value is left at zero then it would have no affect.

That seems ok.
Thank you.

I think the end result will be:

Remove "Torch Of Delay"

Add "Pause At End Of Cut" to the Cut Parameters of the Run Panel which also means it appears in the material file if you use one.

"Pause At End Of Cut" will be a part of the plasmac component so it will be automatically applied to every cut.

There is no need for anything in the GCode file to use this feature, so also no need for anything in a post processor if you use one.

Well, there weren't any no votes so I have the "Pause At End" of cut working as described and am ready to push it.

1. motion stops at end of cut
2. torch off signal
3. dwell for "Pause At End" seconds
4. Z axis rises

All done in the component so no GCode required.

Before I went to push it I had another read through of this thread and this post from Rod got me second guessing myself so I had a look around and found this thread on CNCzone

After reading Jim Colts responses I am thinking I have it wrong and 2 and 3 above should be reversed.

Or are both methods practical.

After reading the links I agree with your assessment, 2 and 3 should be reversed.

One thought for having both functionality might be allowing the machine to cool a bit after high amperage cuts.

thefabricator03 wrote:

snowgoer540 wrote:

After reading the links I agree with your assessment, 2 and 3 should be reversed.

I agree that the 2 and 3 should be swapped.

I have not had time over the last week to do any testing Phil, but I have a lot of work lined up for my machine so I will do some testing of these settings over the next week or so. Ive got to cut a sheet of 20mm,16mm,10mm and 8mm so I will get to see how it affects the cut for the different thicknesses.

Stefan, this will be different to what you have in the update I sent you for testing so I will need to do a new one for you. I did a "clean up" on my computers over the last couple of weeks and I inadvertently deleted too much.
Can you send me your config again and I will patch it with the new stuff.

rodw wrote:

Yeh, i'm pretty sure that is how it should be too. I think also that implies that the delay needs to be tied to the material file. We don't want to have global settings for a thing that varies.

Yes, I agree.