unsolved Misunderstanding of toolpath

[Michel Elsass]

Hello Everybody,
I'm new to this field as well as in CNC machining and I have a misunderstanding, let me explain
I'm trying to make a rounded machining of the width of my tool and when I export my toolpath it gives me the contour of my machining, So I've got a lot more machining to do than I'd like, I don't understand, could you tell me where is the problem?.

Thank's a lot for your answers

Below is the code generated by DXF2GCODE

(Generated with: DXF2GCODE)
(Version: Py3.11.1 PyQt5.15.8, Date: [imath]Date: Mon Feb 6 21:49:45 2023 +0100[/imath])
(Créé à partir du fichier: G:/Test.DXF)(Used Postprocessor: postpro_config.cfg)
(Output format description: G-CODE for LinuxCNC)
(Heure: Mon Oct 28 13:16:40 2024)G21 (Units in millimeters)
G90 (Absolute programming)
G64 (Default cutting) G17 (XY plane) G40 (Cancel radius comp.) G49 (Cancel length comp.)
G0 Z 15.000

(*** LAYER: 0 ***)
T1 M6
S10000

(* SHAPE Nr: 67 *)
G0 X 24.684 Y 30.153
M3
G0 Z 12.000
F150
G1 Z 7.000
F400
G2 X 25.805 Y 60.915 I 39.613 J 13.958 (why does it generate multiple lines?)
G2 X 28.554 Y 59.715 I 1.375 J -0.600
G3 X 27.513 Y 31.150 I 35.742 J -15.604
G2 X 24.684 Y 30.153 I -1.415 J -0.498
F150
G1 Z 6.000
F400
G2 X 25.805 Y 60.915 I 39.613 J 13.958
G2 X 28.554 Y 59.715 I 1.375 J -0.600
G3 X 27.513 Y 31.150 I 35.742 J -15.604
G2 X 24.684 Y 30.153 I -1.415 J -0.498
F150
G1 Z 5.000
F400
G2 X 25.805 Y 60.915 I 39.613 J 13.958
G2 X 28.554 Y 59.715 I 1.375 J -0.600
G3 X 27.513 Y 31.150 I 35.742 J -15.604
G2 X 24.684 Y 30.153 I -1.415 J -0.498
F150
G1 Z 4.000
F400
G2 X 25.805 Y 60.915 I 39.613 J 13.958
G2 X 28.554 Y 59.715 I 1.375 J -0.600
G3 X 27.513 Y 31.150 I 35.742 J -15.604
G2 X 24.684 Y 30.153 I -1.415 J -0.498
F150
G1 Z 3.000
F400
G2 X 25.805 Y 60.915 I 39.613 J 13.958
G2 X 28.554 Y 59.715 I 1.375 J -0.600
G3 X 27.513 Y 31.150 I 35.742 J -15.604
G2 X 24.684 Y 30.153 I -1.415 J -0.498
F150
G1 Z 2.000
F400
G2 X 25.805 Y 60.915 I 39.613 J 13.958
G2 X 28.554 Y 59.715 I 1.375 J -0.600
G3 X 27.513 Y 31.150 I 35.742 J -15.604
G2 X 24.684 Y 30.153 I -1.415 J -0.498
F150
G1 Z 1.000
F400
G2 X 25.805 Y 60.915 I 39.613 J 13.958
G2 X 28.554 Y 59.715 I 1.375 J -0.600
G3 X 27.513 Y 31.150 I 35.742 J -15.604
G2 X 24.684 Y 30.153 I -1.415 J -0.498
F150
G1 Z 0.000
F400
G2 X 25.805 Y 60.915 I 39.613 J 13.958
G2 X 28.554 Y 59.715 I 1.375 J -0.600
G3 X 27.513 Y 31.150 I 35.742 J -15.604
G2 X 24.684 Y 30.153 I -1.415 J -0.498
F150
G1 Z 12.000
G0 Z 15.000
G0 X 0.000 Y 0.000
M30 (Program end)

 

[chrisko]

I don't understand your question fully, but i guess your question is why you are milling that contour. I guess your dxf is showing exactly the same contour as the jpg but only at one height. In order to have a cutter offset you need to active cutter compensation (G41 or G42) with the tool diameter you are using (should be smaller then the contour you want to cut. The other method might be just to draw a rounded line at the center of your cutter and not use cutter compensation like you did it.

 

[Michel Elsass]

Good evening Chrisko, I'm making slow progress, some pockets are good and others are not, the good ones have a blue line (the axis) in the middle and the others, though set up exactly the same, don't even appear when I convert to Gcode, would you have any idea of my problem?
thanks a lot

 

[chrisko]

Can you atttach the dxf and also tell us, which tool diameter you want to use to cut the pockets

 

[Michel Elsass]

Re Good evening Chrisko,
here is the DXF the fan holes and the mounting holes (the small round holes) are to be taken out with a 3 mm tool and the rest with a 6 mm tool.
But I would have liked to know how to do it and find out why it reacts differently to different holes., not for someone to make the file for me.
thank you very much for your help

 

[chrisko]

Hi, your right. There is an issue with the tool. I will check, but can not tell you now, if i will find a fast fix for it. This is a tolerance issue of not exact matching points and arc's which is already know but not easy to fix in general. However i will try in the next few days ...
Christian

 

[Michel Elsass]

Hello Chrisko,
I had an idea, tonight I'm going to test with a hole on the plane 0.1 mm larger to see if it is related to the diameter of the tool. I'll keep you informed too.
Thanks a lot

 

[chrisko]

Hi Michel,
i found the "error" it was a tolerance issue of the dxf. I just needed to reduce the import tolerance of dxf2gcode offset algorithm to find colinear lines. But did take me 2-3 hours to find out ...
New source files available on sourceforge and i also created a new windows installer.
regards
Christian

 

[Michel Elsass]

Hello Christian,
thank you very much
I was wondering if, as a thank you, you'd be interested in me translating the whole interface into French.

Hallo Christian!
vielen Dank
Ich habe mich gefragt, ob es dich interessieren würde, wenn ich die gesamte Benutzeroberfläche ins Französische übersetzen würde, um dir zu danken.

Michel

 

[chrisko]

Hi Michel,
thank you for your proposal. The tool was already translated to french some year ago, i guess there have been some changes since that, so please have a lot here:

dxf2gcode / SourceCode / [932116] /source/i18n

sourceforge.net

I think i did that with a tool called QT Linguist
regards
Christian