No underspeed with temporary material

What version are you on? There were issues with adaptive feed that have been resolved.  A simple update may fix your problem.

That is not really helpful, need to know the QtPlasmaC version in the window's header.

For what it's worth, I ran your G-Code on v2.10-009.071, it runs fine.

I added a feature in 2.10 that changes the "VEL:" label to show when a reduction is present. In this case, the line read "VEL@60%: 1020"

It should be fixed in that version:

forum.linuxcnc.org/plasmac/53657-holes-3...iour?start=20#308841

But probably you should try updating.

I will try to make some time to have a play with your CAM code.

You should be careful what you wish for, I'm known for breaking software and finding bugs in these parts It's kind of how I got my start into the LinuxCNC project.  Phill probably still has nightmares haha but maybe I made up for it in the later years. 

Feedback:

1.  I'm not keen on the idea of uploading my dxf files to a random website (no offense intended).  Probably has to do with my line of work for my day job, but even still I can imagine there would be customers that would be upset about that if they consider their work proprietary or NDA, etc. (dead horse beat).  That said, I can see the convenience aspect as well.  Nothing to install, just internet connection.  I still prefer local software.  Don't worry I have plenty of benign dxfs to upload.  

2.  There are two types of countries:  Those who use the metric system, and those who have been to the moon (I know, I know, you guys are right, the metric system is easier, but I still prefer the dinosaur units over here).  So the attached dxf file is one that I exported in imperial units.  I am not sure what your software made of it, but it doesn't seem right since the size in the bottom says 46.59mm x 9.37mm.  I'm fairly certain it's 46.69in x 9.37in.  Seems like you have at least some plan to handle units as the lead in/out section says "units".

3.  The zoom is a bit wonky.  The movement is very small with my mouse wheel.  It "feels" like when you get zoomed too far in in CAD and the mouse wheel is less effective.

4.  In the Prepare section, the "Apply" buttons are a little confusing to me.  It seems intended to just click the top most apply, but the other ones (except detect chains) seem to do nothing, and then 3 of them are greyed out? 

5.  In Program, it wasn't immediately apparent to me where I go to add a tool.  Of course these are all in the metric system, but I accepted the defaults to have a play.  The kerf was hilariously large so I went back and made it smaller, but it still seemed ... off.  

6.  In tools, I am not sure a rapid speed is necessary.  Normally these would just be G0 which dont require a speed since it's driven by the machine's settings.  

7.  It's nice that I can add an operation by part.  But it would also be nice to have a "select all" option.

8.  I am not sure what "fit" does next to the lead in/out length?  The default was 5 units which is hilariously large, and checking or unchecking "fit" seems to have no effect.  That said, when I change it to something reasonable (.25), then fit does seem to keep the arc length within the kerf width...

 

9.  It seems to have put the leadin on the wrong side for some of the parts (the ones with an inner "circle").

 

10.  You can also see from the pictures above that it choked on the splines around the outside of the part.  When I simulated this, it moved at an incredible speed around these sections (again I attached the file so you could have a play).  

11.  I am a bit unsure between the Kerf Compensation of Outside, Inside, and Part.  This doesn't seem to be strictly necessary?  Wouldn't the kerf always be toward the scrap (or away from the part)?

12. When I clicked export it says "No paths available. Please create operations first.", but it just let me simulate it?

13. Some maybe helpful notes about cutter compensation: linuxcnc.org/docs/devel/html/plasma/qtpl...:cutter-compensation

I am not sure when you'd actually want to use cutter comp, I've always just relied on the CAM to offset the paths for me, and therefore it renders cutter comp unnecessary.

I think that's enough for one my first go at it haha. Hopefully that doesn't feel like I'm beating you up. Seems like you are working toward a good thing.

I am unsure what all of your goals are for the project, but if you need inspiration, SheetCAM is a pretty good software to try and emulate. I cant think of much I would want to do that it does not. It's nice to have free options for sure!