Profile compensation issue

[skal]

Hi,
I don't if this is how it should work, but I found that when trying to profile a contour using compensation, there's a bug in the GCode generation.
I created a piece 150mm*150m0*1mm that I planned to profile with a 2mm tool diameter.
I have the following settings:

2021-09-27 09_16_06-Window.png (6.87 KiB) Viewed 1422 times

And the generated code starts with:

Code: Select all

G0 Z6.000
G0 X150.707 Y150.707
G0 Z4.000
G1 X150.707 Y150.707 Z-1.000 F900.000
G2 X151.000 Y150.000 Z-1.000 I-0.707 J-0.707 K0.000 F900.000

I don't understand why the first generated G1 command is to 150.707 and not 151.000.
Any idea ?

I have the following Freecad installation:

OS: Windows 10 (10.0)
Word size of FreeCAD: 64-bit
Version: 0.20.25645 (Git)
Build type: Release
Branch: master
Hash: 37d9757399b4c2ec30318eb88d7cd7c508246345
Python version: 3.8.10
Qt version: 5.12.9
Coin version: 4.0.0
OCC version: 7.5.2
Locale: French/France (fr_FR)

[chrisb]

You may have to adjust the precision settings in the Path preferences.

[GeneFC]

Any idea ?

This is normal. Look closely and you will see that the path is starting on a rounded corner.

The standard path for a rectangle always "rolls around the corner" instead of making sharp turns. The end result will be perfectly sharp, however.

This fooled me at first, many years ago, but it works fine.

Gene

[skal]

2021-09-27 17_05_15-Window.png (2.89 KiB) Viewed 1233 times

Thanks for the clarification, it make more sense now