solved dxf2gcode - plasma

[paulsao]

Hello, I would like to know how I can modify the postprocessor to use it in a plasma machine with linuxcnc.

 

[chrisko]

Hello Paul and welcome to the forum.

Just to repeat it for the others who are not aware of our previous conversation:

refer to:

Hi, you can open a topic in our new forum, check here:
ltspiceusers.ch

But i know that i just discussed this with someone else in the old section. Check here first:
Missing lines in output for Laser engraver

However if there are additional questions, just open one in the new forum we don't want to continue with google groups, as they are not that easy to search etc.

regards
Christian

Also you find in the Wiki following pages:
dxf2gcode / Wiki / Postprocessor Configuration
dxf2gcode / Wiki / Postprocessor-Example China Laser Cutter

I guess that a plasma machine is very similar to a laser cutter (also uses X and Y axis only with some command to enable the plasma for cutting). Therefore start with the Laser Cutter example and adapt your post processor in that way and check if you machine can handle it.

So now it's your turn to read those and ask more specific questions. Please tell us what you are missing or with what specific things you are struggling to adapt the post processor.

regards
Christian

 

[paulsao]

Thank you Christian for your help. All the documentation is very neat and I was able to understand a lot of things, I was able to get a g-code for my plasma which works fine but I would like to adapt some automatic things. 1) In plasma cutting to cut circles it is necessary to reduce the speed to 50 or 60% of the cutting speed, I am achieving this manually by adding a g code before and after a circle shape, but I would like it to be the processor automatically identifies the circles and adds that part of code to slow down. 2) I would like to know how I can modify the way the torch enters when making a cut, for example at a right angle or an entry at an angle.

 

[chrisko]

1) In plasma cutting to cut circles it is necessary to reduce the speed to 50 or 60% of the cutting speed, I am achieving this manually by adding a g code before and after a circle shape, but I would like it to be the processor automatically identifies the circles and adds that part of code to slow down.

So you need to change the way how arc's are cut. Therefore the following two lines.

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The way the speed is changed is given here, but this is only called at the begin of each shape.

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So you need to add it to the previous commands upfront and call it afterward to resume with normal speed. Your not able to calculate it based on the nominal speed, but find the example with defining a speed of 50 for all circles ....

Bitte, Anmelden oder Registrieren to view codes content!

2) I would like to know how I can modify the way the torch enters when making a cut, for example at a right angle or an entry at an angle.

This is more difficult. This is not implemented by an option or similar right now. You would be required to modify the code. In general this is done in the following function:
dxf2gcode / SourceCode / [e6eddf] /source/dxf2gcode/core/shape.py

 

[paulsao]

I think I've already managed to make the necessary changes, now at the time of cutting I realized something: the tool compensation is already calculated by the program? because at the time of cutting it seems that it does not perform any compensation in the g code. Should the compensation be done on the machine?

 

[paulsao]

It was just to uncheck a box . But I realized that when I use the compensation from the program the entry arc disappear, is there any way to put them back.

 

[chrisko]

The entry move is only there when using the machine compensation.

 

[paulsao]

The entry move is only there when using the machine compensation.

I imagined it, that's the only thing I would need to change in the code.

 

[paulsao]

I just want to know what is the function that creates the entries, to be able to modify it would be of great help.

 

[chrisko]

Shapes are created here prior to plotting to the windows:
dxf2gcode / SourceCode / [e6eddf] /source/dxf2gcode.py

Start moves are created as an action from the GUI here (and also in same file with ending 3d i guess):
dxf2gcode / SourceCode / [e6eddf] /source/dxf2gcode/gui/canvas2d.py

The general creation is inherited from here, where those moves are created finally (your answer).
dxf2gcode / SourceCode / [e6eddf] /source/dxf2gcode/core/stmove.py

This one is selecting which part is exported to the G-Code
dxf2gcode / SourceCode / [e6eddf] /source/dxf2gcode/core/shape.py

Somewhere around there you also find the difference between compensation done by machine or program. I know this is something which should be refactored, but i currently don't have the will / time to do it. I hope you find your way through it, otherwise feel free to ask.

 

[paulsao]

Is there any way to create the circles other than by quadrant arcs? since to form a circle the g code provides 2 lines corresponding to the arcs that form the circle, can I change the format to generate it in just one line?

 

[chrisko]

Yes, you can create a 360° length arc, which is a full circle. However you still need to specificy the start and end point ....

 

[paulsao]

Could you help me how is the input format, I found something like this:
arc_int_cw = Ps=Point(%XS, %YS), Pe=Point(%XE, %YE), O= Point(%XO, %YO, s_ang=radians(%AngS ), e_ang=radians(%AngE ),r=%R,address=%ext),%nl"

 

[chrisko]

I am not sure about your question. What are you trying to achieve?

Note: Your not able to add a arc here, just to be clear, this is the way how the Postprocessor exports an given arc geometry to a defined g-code style.

 

[chrisko]

did you solve the topic? Can i close it?

 

[chrisko]

Closed, since no further feedback here ....