Path profile corner handeling

Here's the place for discussion related to CAM/CNC and the development of the Path module.
Konstantin
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Path profile corner handeling

Postby Konstantin » Thu Jul 06, 2017 1:31 pm

Hello.
I finally get working FreeCAD, broken machine (not my fault :) ) and some time today while waiting spare parts.
It's all started in this thread, sliptonic convinced me to use Job and "Profile based on faces" tool for more advanced work with plasma. Created separate thread, because it is not related to my post directly, but cowers more areas.

Profiling now has a beautiful feature, if I use tool compensation, it creates a path that smoothly rounds around the corner. It's brilliant, not all CAMs have this feature. This is good for milling. But unfortunately this feature is bad for plasma and some lasers. Some machines has automatic corner handling, lowering amperage, and some other parameters before making turn. Soin fact this machines NEED a sharp turn, or it will (a bit) burn the corner dancing around it.

So. Is it a big problem to add such option in path generation a sharp corners?
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sliptonic
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Re: Path profile corner handeling

Postby sliptonic » Thu Jul 06, 2017 2:01 pm

Konstantin wrote:
Thu Jul 06, 2017 1:31 pm
So. Is it a big problem to add such option in path generation a sharp corners?
Actually, I think it's pretty easy. @realthunder exposed the jointype property of the clipperlib which controls this. I can add the additional properties to the contour and profile operations pretty easily.

To get the effect you want, there will actually be two new properties.
Jointype will default to 'round' and give the current behavior. It will have two other options for 'square' and 'miter'. 'Miter' is what you're after but there's a threshold control that sets the limit to avoid long spikes if the angle is very acute. See more here

Please add a feature request to the tracker and put a link in this thread.
Konstantin
Posts: 261
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Re: Path profile corner handeling

Postby Konstantin » Thu Jul 06, 2017 2:40 pm

sliptonic wrote:
Thu Jul 06, 2017 2:01 pm
Actually, I think it's pretty easy. @realthunder exposed the jointype property of the clipperlib which controls this. I can add the additional properties to the contour and profile operations pretty easily.

To get the effect you want, there will actually be two new properties.
Jointype will default to 'round' and give the current behavior. It will have two other options for 'square' and 'miter'. 'Miter' is what you're after but there's a threshold control that sets the limit to avoid long spikes if the angle is very acute. See more here
So you say it almost there? Wow!
Please add a feature request to the tracker and put a link in this thread.
Done
It would be wonderful.
herbk
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Re: Path profile corner handeling

Postby herbk » Thu Jul 06, 2017 3:24 pm

Hi,
doesn't "set the path to on" make the same?

I use it if i want to use a external machine of a shop where i not know which tolls are availible. They use LinuxCNC which has a includet "tool and corner management" also and it works fine with an uncompensated path.
Last edited by herbk on Thu Jul 06, 2017 3:34 pm, edited 1 time in total.
Gruß Herbert
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sliptonic
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Re: Path profile corner handeling

Postby sliptonic » Thu Jul 06, 2017 3:33 pm

herbk wrote:
Thu Jul 06, 2017 3:24 pm
Hi,
doesn't "set the path to on" make the same?
Only if you do cutter compensation in the control. He wants Path to calculate the offset but not round the corners.
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bill
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Re: Path profile corner handeling

Postby bill » Thu Jul 06, 2017 3:38 pm

Having run a LINDE Plasma machine years ago, i understand your concern. It had big problems with ACUTE corners. However, pulling my past thoughts and experience out of thin air, I would guess that staying on the line ( as suggested by herbkkkk) and post processing for specifics, like stock thickness, feed, amperage, and torch height, etc, would be more appropriate. Good luck with this one! Typically, we would finish the job by the time all the tweaks achieved max results. Just sayin!
herbk
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Re: Path profile corner handeling

Postby herbk » Thu Jul 06, 2017 3:48 pm

ah, ok,
but need this machines a offset? doesn't they calculate it also by itself?
Some Lasercutters (of firms i work with) does it, becouse they can change the diameter off the beam and so they calculate the offset, fitting to the beam, to.
Gruß Herbert
Konstantin
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Re: Path profile corner handeling

Postby Konstantin » Thu Jul 06, 2017 5:06 pm

herbk wrote:
Thu Jul 06, 2017 3:48 pm
ah, ok,
but need this machines a offset? doesn't they calculate it also by itself?
Some Lasercutters (of firms i work with) does it, becouse they can change the diameter off the beam and so they calculate the offset, fitting to the beam, to.
Some machines run always "on left" of line, then you don't need to care about tool offset, some even have fixed offset. Some small lasers always cut in the middle, but their kerf diameter is insignificant. Rest can run without offset, or with offset, on left, on right, you must specify it in the program. But this feature is not supported by FreeCAD, as I understand, I have to generate the path with offset in FreeCAD. This is acceptable (at least to me), but here comes sharp corner problem.