How to engrave a line?

Here's the place for discussion related to CAM/CNC and the development of the Path module.
micksulley
Posts: 78
Joined: Fri May 11, 2018 9:28 am

How to engrave a line?

Postby micksulley » Mon Oct 22, 2018 10:15 pm

OS: Linux Mint 19 Tara
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.14995 (Git) AppImage
Build type: Release
Branch: master
Hash: 7b866816785ac1ca9787b63d4bff12873bb3a593
Python version: 2.7.6
Qt version: 4.8.6
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/UnitedKingdom (en_GB)

i am trying to engrave some lines on a plate but can't figure it out, see attached file. If I have SketchEngraveLines under the body, as shown, I cannot see the lines to add them as the base geometry for the engrave operation. If I move it to the same level as Body I can see the lines but still cannot add them to the Base Geometry. I have used Map Sketch to Face in Part Design
Also SketchEngraveLines shows an error marker, Error, Internal name: Sketch001 - that was the original name. Is that relevant?

What am I doing wrong?
Thanks
Mick
Attachments
RJ45x7v5Frm.fcstd
(17.67 KiB) Downloaded 25 times
chrisb
Posts: 18759
Joined: Tue Mar 17, 2015 9:14 am

Re: How to engrave a line?

Postby chrisb » Tue Oct 23, 2018 6:25 am

The engraving operation works with ShapeStrings. If you want to generate GCode following the lines you can use "Path from shape". Please note, that this operation is not inside of the job.
micksulley
Posts: 78
Joined: Fri May 11, 2018 9:28 am

Re: How to engrave a line?

Postby micksulley » Tue Oct 23, 2018 7:14 am

Sorry Chris I don't understand. What is "Path from shape"? I don't see an icon or a menu option for that.
chrisb
Posts: 18759
Joined: Tue Mar 17, 2015 9:14 am

Re: How to engrave a line?

Postby chrisb » Tue Oct 23, 2018 11:50 am

Path FromShapes says you have to enable Path experimental. Then you find it in Menu->Path->SupplementalCommands.
mlampert
Posts: 1326
Joined: Fri Sep 16, 2016 9:28 pm

Re: How to engrave a line?

Postby mlampert » Tue Oct 23, 2018 7:49 pm

There are two issues here, a general and a Path specific.

There is a cycle dependency in your model. SketchEngraveLines seems to depend on itself. Not sure how you got there but you might want to fix that, FC does unpredictable things in situations like this (at least they are unpredictable for me)

The second issue is a combination of how PartDesign works and how Path uses those. The short answer is, you can only use the Body as a base model for a Path.Job, and Path uses whatever Shape that Body has. In your case that is the rectangular bar. So if you want to use SketchEngraveLines as a base model for a Job you need to move it out of Body. Once you do that you can add it to the Model of the Job and use its edges for engraving.
chrisb
Posts: 18759
Joined: Tue Mar 17, 2015 9:14 am

Re: How to engrave a line?

Postby chrisb » Tue Oct 23, 2018 8:22 pm

I reattached the sketch to XY plane which fixes the self reference.
Alas, PathShape produces again a "Links go out of the allowed scope message and a read arrow in the dependency graph.

At a quick glance the gcode produced looks sensible.
Attachments
RJ45x7v5Frm_cb.FCStd
(8.86 KiB) Downloaded 17 times
micksulley
Posts: 78
Joined: Fri May 11, 2018 9:28 am

Re: How to engrave a line?

Postby micksulley » Tue Oct 23, 2018 10:46 pm

Just looked at your file. A few things -
I had to add a job in order to use Inspect G-Code, otherwise that option is greyed out.
I changed the Z position in the sketch to -0.05mm, I guess it will not cut otherwise
The g-code generated will cut across from the end of the first line to the end of the second, etc, rather than raise to a safe height to move.
Does the g-code get saved anywhere? I can't see it.

Thanks for your help
Mick
chrisb
Posts: 18759
Joined: Tue Mar 17, 2015 9:14 am

Re: How to engrave a line?

Postby chrisb » Wed Oct 24, 2018 5:29 am

I'm not familiar with this operation either, but as it's experimental, I can accept that it's not finished yet. I didn't realize that you have to create a job, because deleting the job was the last thing I did before saving.
I had hoped that changing the properties directly would lift the engraver but properties like Retraction or ResumeHeight did not have any visible effect.

If possible you can cheat here and fool the operation by making the lines in the sketch a bit longer.

Instead of lowering the sketch you can change the placement of the PathShape operation as well.
herbk
Posts: 1530
Joined: Mon Nov 03, 2014 3:45 pm
Location: Windsbach, Bavarya (Germany)

Re: How to engrave a line?

Postby herbk » Wed Oct 24, 2018 6:13 am

Hi Mick,
micksulley wrote:
Tue Oct 23, 2018 10:46 pm
Does the g-code get saved anywhere?
to save a "Path from shape" gcode, you have to select the path in object tree and export it by using File ->export. Saving by using the "Export Gcode" button dos not work.
Gruß Herbert
micksulley
Posts: 78
Joined: Fri May 11, 2018 9:28 am

Re: How to engrave a line?

Postby micksulley » Wed Oct 24, 2018 3:28 pm

OK Guys thanks for the help. I accept that it is experimental and I will experiment a bit more.

Probably be back with more questions.......
cron