Error while generating a circular path?

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Giulio Buccini
Posts: 541
Joined: Fri Aug 26, 2016 9:07 pm
Location: Munich - Gemany

Error while generating a circular path?

Post by Giulio Buccini »

I've generated the code to mill an U-Washer from Delrin material.

My first operation is a rough cleaning of the circular pocket, before finishing the walls. For this task I've generated an edge-milling operation with some offset:
Selection_7416.jpg
Selection_7416.jpg (14.46 KiB) Viewed 1523 times
(End-mill dia = 2 mm)

Only today I discovered that... there is a G1 instruction (linear movement) in the middle of the circular path. :shock:
Is this normal?
I'm missing something?
:?
Selection_7415.jpg
Selection_7415.jpg (112.51 KiB) Viewed 1523 times
I attach the FCstd file.

--------------------------------------------------
OS: Ubuntu 16.04.7 LTS (XFCE/xfce)
Word size of FreeCAD: 64-bit
Version: 0.20.25065 (Git) AppImage
Build type: Release
Branch: master
Hash: 4de2ad46b2b9c78ac2721a0dbea7c19306261095
Python version: 3.9.4
Qt version: 5.12.9
Coin version: 4.0.0
OCC version: 7.5.2
Locale: English/United States (en_US)
Attachments
U-Scheiben-1.0.FCStd
(41.95 KiB) Downloaded 29 times
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sliptonic
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Re: Error while generating a circular path?

Post by sliptonic »

Looks like curve accuracy thing.
Increase your accuracy here and recompute.
2021-06-23_14-59.png
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Giulio Buccini
Posts: 541
Joined: Fri Aug 26, 2016 9:07 pm
Location: Munich - Gemany

Re: Error while generating a circular path?

Post by Giulio Buccini »

1. raised tolerance and accuracy to 0,001 mm
2. "apply" button pressed
3. "ok" button pressed
4. Freecad restarted
5. file loaded
6. "post process" button pressed and file saved

The resulting gcode is the same: still 185 lines of code with no changes. :(
Attachments
Selection_7418.jpg
Selection_7418.jpg (52.43 KiB) Viewed 1455 times
Giulio Buccini
Posts: 541
Joined: Fri Aug 26, 2016 9:07 pm
Location: Munich - Gemany

Re: Error while generating a circular path?

Post by Giulio Buccini »

Maybe I have to updated the Path Workbench?
Unfortunately it is not listed in the Addon-manager list...

P.S.
I tried also to set 0,0001 mm as value for Tolerance and accuracy both. Again no changes in the output code.
chrisb
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Re: Error while generating a circular path?

Post by chrisb »

Giulio Buccini wrote: Thu Jun 24, 2021 6:14 am Maybe I have to updated the Path Workbench?
Path workbench belongs to the core system. It updates when you update FreeCAD.
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Giulio Buccini
Posts: 541
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Location: Munich - Gemany

Re: Error while generating a circular path?

Post by Giulio Buccini »

I was thinking about that...

Any idea about the problem?
chrisb
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Re: Error while generating a circular path?

Post by chrisb »

I don't see these G1 commands, this is the pocket1/2 part:

Code: Select all

(begin operation: pocket-1/2)
(machine units: mm/min)
(pocket-1/2) 
(Compensated Tool Path. Diameter: 2.0) 
G0 Z5.000 
G0 X7.482 Y7.482 
G0 Z3.000 
G1 X7.482 Y7.482 Z-0.800 F120.000 
G3 X5.585 Y8.054 Z-0.800 I-1.482 J-1.482 F799.998 
G3 X6.415 Y3.946 Z-0.800 I0.415 J-2.054 F799.998 
G3 X7.482 Y7.482 Z-0.800 I-0.415 J2.054 F799.998 
G1 X7.482 Y7.482 Z-1.600 F120.000 
G3 X5.585 Y8.054 Z-1.600 I-1.482 J-1.482 F799.998 
G3 X6.415 Y3.946 Z-1.600 I0.415 J-2.054 F799.998 
G3 X7.482 Y7.482 Z-1.600 I-0.415 J2.054 F799.998 
G1 X7.482 Y7.482 Z-2.400 F120.000 
G3 X5.585 Y8.054 Z-2.400 I-1.482 J-1.482 F799.998 
G3 X6.415 Y3.946 Z-2.400 I0.415 J-2.054 F799.998 
G3 X7.482 Y7.482 Z-2.400 I-0.415 J2.054 F799.998 
G0 Z5.000 
G0 Z5.000 
(finish operation: pocket-1/2)
I have set both tolerance values to 1µm.
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Giulio Buccini
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Joined: Fri Aug 26, 2016 9:07 pm
Location: Munich - Gemany

Re: Error while generating a circular path?

Post by Giulio Buccini »

Nevertheless, I still see that G1 instructions in my output file:

Code: Select all

(begin operation: pocket-1/2)
(machine units: mm/min)
(Profile001) 
(Compensated Tool Path. Diameter: 2.0) 
G0 Z5.000 
G0 X7.482 Y7.482 
G0 Z3.000 
G1 X7.482 Y7.482 Z-0.800 F120.000 
G3 X5.574 Y8.052 Z-0.800 I-1.482 J-1.482 F799.998 
G3 X6.415 Y3.946 Z-0.800 I0.427 J-2.052 F799.998 
G1 X6.679 Y4.017 Z-0.800 F799.998
G3 X7.482 Y7.482 Z-0.800 I-0.679 J1.982 F799.998 
G1 X7.482 Y7.482 Z-1.600 F120.000 
G3 X5.574 Y8.052 Z-1.600 I-1.482 J-1.482 F799.998 
G3 X6.415 Y3.946 Z-1.600 I0.427 J-2.052 F799.998 
G1 X6.679 Y4.017 Z-1.600 F799.998
G3 X7.482 Y7.482 Z-1.600 I-0.679 J1.982 F799.998 
G1 X7.482 Y7.482 Z-2.400 F120.000 
G3 X5.574 Y8.052 Z-2.400 I-1.482 J-1.482 F799.998 
G3 X6.415 Y3.946 Z-2.400 I0.427 J-2.052 F799.998 
G1 X6.679 Y4.017 Z-2.400 F799.998 
G3 X7.482 Y7.482 Z-2.400 I-0.679 J1.982 F799.998 
G0 Z5.000 
G0 Z5.000 
(finish operation: pocket-1/2)
Attachments
U-Scheiben-1.0-again.txt
(6.53 KiB) Downloaded 18 times
Giulio Buccini
Posts: 541
Joined: Fri Aug 26, 2016 9:07 pm
Location: Munich - Gemany

Re: Error while generating a circular path?

Post by Giulio Buccini »

I tried to set the tolerance/accuracy to 0.0001 mm, but I got the same output file.
In order to set 1 micrometer I should set the Preferences to allow 6 decimal digit. This could be quite annoying when entering values through the general Freecad interface...

UPDATE
-------------------------
I tried to set the accuracy/tolerance to 1 micrometer. No way, the G1 instruction is still there.... :o
Selection_7419.jpg
Selection_7419.jpg (23.38 KiB) Viewed 1384 times
Syres
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Re: Error while generating a circular path?

Post by Syres »

chrisb wrote: Thu Jun 24, 2021 8:03 am I don't see these G1 commands, this is the pocket1/2 part:

I have set both tolerance values to 1µm.
I have to confirm the OP report with the tighter tolerance values:

Code: Select all

(begin operation: pocket-1/2)
(machine units: mm/min)
(Profile001) 
(Compensated Tool Path. Diameter: 2.0) 
G0 Z5.000 
G0 X7.482 Y7.482 
G0 Z3.000 
G1 X7.482 Y7.482 Z-0.800 F120.000 
G3 X5.574 Y8.052 Z-0.800 I-1.482 J-1.482 F799.998 
G3 X6.415 Y3.946 Z-0.800 I0.427 J-2.052 F799.998 
G1 X6.679 Y4.017 Z-0.800 F799.998 
G3 X7.482 Y7.482 Z-0.800 I-0.679 J1.982 F799.998 
G1 X7.482 Y7.482 Z-1.600 F120.000 
G3 X5.574 Y8.052 Z-1.600 I-1.482 J-1.482 F799.998 
G3 X6.415 Y3.946 Z-1.600 I0.427 J-2.052 F799.998 
G1 X6.679 Y4.017 Z-1.600 F799.998 
G3 X7.482 Y7.482 Z-1.600 I-0.679 J1.982 F799.998 
G1 X7.482 Y7.482 Z-2.400 F120.000 
G3 X5.574 Y8.052 Z-2.400 I-1.482 J-1.482 F799.998 
G3 X6.415 Y3.946 Z-2.400 I0.427 J-2.052 F799.998 
G1 X6.679 Y4.017 Z-2.400 F799.998 
G3 X7.482 Y7.482 Z-2.400 I-0.679 J1.982 F799.998 
G0 Z5.000 
G0 Z5.000 
(finish operation: pocket-1/2)
Another difference I noticed is on your 3rd line lists the Operation Label (pocket-1/2) whereas on mine and the OP's it's the Operation Name (Profile001), is that a personal tweak on the post processor on your side?


OS: Linux Mint 19.3 (X-Cinnamon/cinnamon)
Word size of FreeCAD: 64-bit
Version: 0.20.25148 (Git)
Build type: Release
Branch: master
Hash: 835e3266525580ed3c5fa47e27b33431840d62ee
Python version: 3.6.9
Qt version: 5.9.5
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/UnitedKingdom (en_GB)
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