qcad profile cut
Moderator: andrew
Forum rules
Always indicate your operating system and QCAD version.
Attach drawing files and screenshots.
Post one question per topic.
Always indicate your operating system and QCAD version.
Attach drawing files and screenshots.
Post one question per topic.
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1engravecut
- Newbie Member
- Posts: 3
- Joined: Tue Jan 06, 2026 3:45 pm
qcad profile cut
i inside cut a square 2" x 2" i use bit 0.124" cut result is 2.124" x 2.124" i cut again same size square machine cuts out exact cut out again 2.124" x 2.124" what i am doing wrong? thank you
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1engravecut
- Newbie Member
- Posts: 3
- Joined: Tue Jan 06, 2026 3:45 pm
Re: qcad profile cut
sorry forgot to say in in 2nd cut i input different size cutter 0.622 bit
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CVH
- Premier Member
- Posts: 5097
- Joined: Wed Sep 27, 2017 4:17 pm
Re: qcad profile cut
Hi, and welcome to the QCAD forum.
Sounds like a QCAD/CAM question.
You probably cut 'On path' and don't compensate the cutter diameter.
The CNC-driver follows the path with the cutter centered on the path.
Hence, it will be 1/2 cutter wider at one edge and another 1/2 diameter wider at the opposite edge.
To compensate we chose Left or Right of path and that according the milling method 'Conventional' or 'Climbing'
Compensation can be done in 2 ways.
- Or QCAD/CAM exports an offset path (G40).
- Or you use G41/42 and your CNC-driver does the rest.
For the latter QCAD/CAM exports the paths as they are.
Also check whether your driver is G41/42 capable, otherwise these instructions may be skipped.
And whether you use a post-processor intended for G41/42 or for a calculated offset.
A post-processor that exports a calculated offset typically has 'offset' in it description.
The 0.622" cutter size with the same result doesn't make any sense to me.
With offsetting to a path, calculated or G41/42, always use the programmed size cutter.
QCAD/CAM, nor your CNC-driver can verify the actual tool size.
Regards,
CVH
Sounds like a QCAD/CAM question.
You probably cut 'On path' and don't compensate the cutter diameter.
The CNC-driver follows the path with the cutter centered on the path.
Hence, it will be 1/2 cutter wider at one edge and another 1/2 diameter wider at the opposite edge.
To compensate we chose Left or Right of path and that according the milling method 'Conventional' or 'Climbing'
Compensation can be done in 2 ways.
- Or QCAD/CAM exports an offset path (G40).
- Or you use G41/42 and your CNC-driver does the rest.
For the latter QCAD/CAM exports the paths as they are.
Also check whether your driver is G41/42 capable, otherwise these instructions may be skipped.
And whether you use a post-processor intended for G41/42 or for a calculated offset.
A post-processor that exports a calculated offset typically has 'offset' in it description.
The 0.622" cutter size with the same result doesn't make any sense to me.
With offsetting to a path, calculated or G41/42, always use the programmed size cutter.
QCAD/CAM, nor your CNC-driver can verify the actual tool size.
Regards,
CVH