Pocket Contour Cutting Help (using Path WB)

Here's the place for discussion related to CAM/CNC and the development of the Path module.
taddytoo
Posts: 4
Joined: Tue Jun 02, 2020 6:50 pm

Pocket Contour Cutting Help (using Path WB)

Postby taddytoo » Tue Jul 21, 2020 2:57 pm

OS: macOS 10.14
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.16146 (Git)
Build type: Release
Branch: (HEAD detached at 0.18.4)
Hash: 980bf9060e28555fecd9e3462f68ca74007b70f8
Python version: 3.6.7
Qt version: 5.6.2
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/UnitedStates (en_US)


Hi, sorry if this is posted elsewhere, I searched and read most of the posts pertaining to this issue, but still wasn't able to figure out what I needed to do. We are cutting .25" acrylic, and I am having a hard time figuring out how to get the interior pocket cuts to happen. I read that you have to make a profile cut for the pocket to have it cut as well, but everything I tried had it trying to mill out the big circle whereas I just want it to cut along the line. Basically just have the CNC cut a rectangle, and also cut a hole in the middle of the rectangle. Other instances would be for bubble words, to cut the inside of the letters out as well as the outline of the whole piece. Sorry again if this has been covered before just been struggling to understand. Attached file
Thanks!!
Attachments
fancutout_1.FCStd
(30.33 KiB) Downloaded 18 times
Last edited by jmaustpc on Tue Jul 21, 2020 3:11 pm, edited 1 time in total.
Reason: added "(using Path WB)" to topic title
jmaustpc
Posts: 9991
Joined: Tue Jul 26, 2011 6:28 am
Location: Australia

Re: Pocket Contour Cutting Help (using Path WB)

Postby jmaustpc » Tue Jul 21, 2020 3:17 pm

I must admit that although I think Path WB is a very important thing, I have not used it myself, so I can't help much. I added "(using Path WB)" to your topic title to attract someone with the knowledge required.

Having said that a tip and question...
Firstly download the latest snapshot of FreeCAD 0.19, there are a lot of bugs, limitations fixed by new features in 0.19, your problem may well be already fixed. Path wb has more tools and features in 0.19.

Secondly, your central circle is a spline, not a circle. You may have intended that of course. It is possible that an issue that appears with a spline may well not with a circle.

Jim
chrisb
Posts: 26941
Joined: Tue Mar 17, 2015 9:14 am

Re: Pocket Contour Cutting Help (using Path WB)

Postby chrisb » Tue Jul 21, 2020 4:28 pm

I would second everything Jim said. As your model looks a bit garbled with these objects Path, Path001 and Sketch001 outside of the body I would even recommend to restart from scratch:

- Place the center of the model in the center of the coordinate system and don't place it in the middle of nowhere
- Use a circle instead of 4 B-splines, you can place the circle already in the first sketch, making the pocket obsolete
- fully constrain your sketches

Then use 0.19 for all Path related stuff. You can create paths for this using profile, both for inner and outer path.

If you face problems, ask back.
taddytoo
Posts: 4
Joined: Tue Jun 02, 2020 6:50 pm

Re: Pocket Contour Cutting Help (using Path WB)

Postby taddytoo » Tue Jul 21, 2020 4:50 pm

Thank you for the advice, will download newer version and report back! I did intend it to be a circle, as its just an illustrator file I saved as SVG, is there a reason with importing that it would turn into 4 splines? My process (that I was taught, but I'm a little blind to the nuances of the program) was import .svg file, scale by .25, move image, draft to sketch, then move to the part design workbench, create the body and then the pad (reversed) and then in path work bench, creating a job followed by contour with the outer cuts. it's worked OK with the sizes sometimes being a little off (this is my first time trying to make anything that involves pocket cut and not just a simple outline shape), but maybe i'm missing something in that processes, am I suppose to delete the sketches after converting them?
Thanks again
jmaustpc
Posts: 9991
Joined: Tue Jul 26, 2011 6:28 am
Location: Australia

Re: Pocket Contour Cutting Help (using Path WB)

Postby jmaustpc » Tue Jul 21, 2020 5:21 pm

taddytoo wrote:
Tue Jul 21, 2020 4:50 pm
is there a reason with importing that it would turn into 4 splines?
Could be that it always was defined as a spline by your software rather than stored as a true svg circle, another possibly is if you have a circle but you import it on a slightly different plane then the circle would become a spline. I think the first is most likely.

Actually I just read your post again, its because you used "scale", most likely. It would have converted your circle to a spline while trying to scale it, if it was not always a spline.
taddytoo wrote:
Tue Jul 21, 2020 4:50 pm
but I'm a little blind to the nuances of the program) was import .svg file, scale by .25, move image, draft to sketch, then move to the part design workbench, create the body and then the pad (reversed) and then in path work bench
You can import a SVG but its a "corner case" for special cases where you need to, its not a good normal work flow. Better to just create the geometry in a sketch in FreeCAD normally.

Why bother with scale? total waste of time if you are going to put it in a sketch. Once the geometry is in a sketch just define it all with constraints. The original size of the SVG import becomes relevant.

Another tip, in most cases you should fully constrain your sketch, it all goes green when in edit mode when you have done so.

i hope this helps.

P.S. Chris knows far more about Path WB than I. I was thinking of buying a lathe/mill or something but decided a tractor was more urgent. The 2 years or so of drought caused many tough decisions. :)

Jim
taddytoo
Posts: 4
Joined: Tue Jun 02, 2020 6:50 pm

Re: Pocket Contour Cutting Help (using Path WB)

Postby taddytoo » Tue Aug 04, 2020 3:15 pm

Thank you for all the help regarding scale and the .svg files (that's just what I had been taught as a very basic use for what we are doing) creating the geometry inside of freecad has helped with some of our mistakes and is easy enough since mostly we are cutting rectangles and squares, though I'm still unsure of how to properly use the newer version of freecad .19 to have it a actually cut out the pocket shapes i'm making using the path workbench. The file i'm attaching is a bit messy, but i'm not sure with a more complicated shape like this if you just have to sit there and recreate all the geometry or if this is something where importing the SVG makes sense. This was just my first bumbling attempt at it (well like my 9th on this same shape..) I was happy to get the pockets to show up but obviously there aren't any cuts around the pocket. I would put my .19 attempt but it doesn't even show any useful information. Are there any suggestions for a better way to create the body and pocket for a shape like this that is based off an illustrator file and needs to be exact? And any one that has experience with creating cut paths for the inside of the Y E and S, seems like it should be easier to figure out but I'm at a total loss. Sorry if I'm just missing something super easy to understand and thank you for the help! This is again for cutting through .25" acrylic
Attachments
yes_cutoutcorrectpockets.FCStd
(374.81 KiB) Downloaded 11 times
herbk
Posts: 1871
Joined: Mon Nov 03, 2014 3:45 pm
Location: Windsbach, Bavarya (Germany)

Re: Pocket Contour Cutting Help (using Path WB)

Postby herbk » Tue Aug 04, 2020 4:50 pm

Hi,
if you are at the last .19, for the cutts inside the Y,E and S select the uper edges and use the Contour OP.

Edit: i would cutt it this way, . and add a few holding tags that the part don't flip arround if the cut is ready. ;-)
yes.jpg
yes.jpg (78.22 KiB) Viewed 328 times
Changing the order of the OPs, the outside cut should be done at last, would show a better result to... :oops: :roll:
Attachments
yes_cutoutcorrectpockets_herbk.FCStd
(338.43 KiB) Downloaded 15 times
Gruß Herbert
chrisb
Posts: 26941
Joined: Tue Mar 17, 2015 9:14 am

Re: Pocket Contour Cutting Help (using Path WB)

Postby chrisb » Tue Aug 04, 2020 8:08 pm

To answer your other question: It is not really sensible to remodel this in FreeCAD. But it is often worth considering to simplify paths in Inkscape before importing to FreeCAD.
taddytoo
Posts: 4
Joined: Tue Jun 02, 2020 6:50 pm

Re: Pocket Contour Cutting Help (using Path WB)

Postby taddytoo » Wed Aug 05, 2020 8:18 pm

That file looks perfect thank you! I'm not sure how you got to where you did but that's exactly what i'm trying to do! When i tried to select the inside paths of the inside of the Y, E, and S, it would just select a little part and not the entire thing, Is there a simple way to select that entire path so that I can turn it into a profile contour? I'm not sure if this is all in the wiki but I hadn't seen it when I checked. The outside all seems simple enough to me but these insides are just making me tear my hair out. You made it seem super easy though if you could just run me through the steps if you had the time! Thanks again. Also will look into inkscapes for the future!
herbk
Posts: 1871
Joined: Mon Nov 03, 2014 3:45 pm
Location: Windsbach, Bavarya (Germany)

Re: Pocket Contour Cutting Help (using Path WB)

Postby herbk » Thu Aug 06, 2020 5:59 am

Hi,
taddytoo wrote:
Wed Aug 05, 2020 8:18 pm
T Is there a simple way to select that entire path so that I can turn it into a profile contour?
yes it is...: just selct 2 edges that share a common vertex and use the Complete Loop button.

https://wiki.freecadweb.org/Path_SelectLoop

Btw.: It's usually a good idea to take a look at the Wiki... ;) ;)
Gruß Herbert