Need to establish workflow - help

jjubenv
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Joined: Thu Dec 12, 2013 6:42 pm
Location: Ontario, Canada

Need to establish workflow - help

Post by jjubenv » Fri Jul 24, 2015 10:52 pm

Hi All.

I have been trying to establish a workflow for my Shapeoko 2. I've successfully made coasters, but not much more complex than that. I want to make a pot holder similar to this link http://incra.com/perry_toolzone_trivets.html and so I made up this object for the center section:
Trivet.png
Trivet.png (82.7 KiB) Viewed 1309 times
I made this in sketchup 2015. It's 6" square and 3/4" thick. Each "Layer" is 1/16 deeper than the next with a total cut depth of about 1/4". I plan on using either Ash or Oak for his piece. I have the stock 'Dremel' tool on my shapeoko and a 1/8" endmill.

I imported a 2d SVG that I made using a sketchup plugin, into maker cam. I made some pockets but couldn't get them correct when I viewed them with OpenSCAM. The view just ended up being a bunch of posts instead of pyramids. The G-Code was really inefficent as well (more moving time than cutting time by far).

I do not know any CAD/CAM package, so I need some advice on how best to get my model into g-code. I have tried HeeksCAD (This seems to just close down without notice), and started to look at FreeCAD but I don't know what I'm doing in this software. I mostly need the CAM features as I think I can use Sketchup->SVG and then tune things up a bit in Inkscape before I start making tool paths.

I've attached my attempt with makercam, I can't upload an SVG as the forum software says it's not allowed, so I zipped it.
Attachments
Trivet with paths.zip
(4.01 KiB) Downloaded 36 times

cozmicray
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Re: Need to establish workflow - help

Post by cozmicray » Sat Jul 25, 2015 1:56 am

You could just use MakerCam.

Make a square path of the base of the small pyramid depth 1/4"
Make a smaller square path of the next smaller step inside the previous of the small pyramid depth 3/16"
Make a smaller square path of the next smaller step inside the previous of the small pyramid depth 1/8"
Make a smaller square path of the next smaller step inside the previous of the small pyramid depth 1/16"

then duplicate this to make entire trivit.

MakerCam will probably crash 84 times so save often.

You could also use Inkscape and use available plugins to
convert to g-code.

:?:

WillAdams
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Re: Need to establish workflow - help

Post by WillAdams » Sat Jul 25, 2015 3:34 am

I believe that this tutorial might help: http://www.shapeoko.com/wiki/index.php/ ... e/MakerCAM

(Linked from: http://www.shapeoko.com/wiki/index.php/MakerCAM )

The concept which will make the paths more efficient would be:
Note that for this second pass, we set our stock surface to be negative, since we're working within the pocket established by the diamond pocketing operation above, so use that operation's target depth for the stock surface.
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets

jjubenv
Posts: 46
Joined: Thu Dec 12, 2013 6:42 pm
Location: Ontario, Canada

Re: Need to establish workflow - help

Post by jjubenv » Sat Jul 25, 2015 3:18 pm

OK, I will do the tutorial first. Cutting the circle/diamond/square will probably help to make sure I've got my machine set up good enough.

Then I will go back to MakerCam with my SVG and try going from the deepest cuts and expand out to the more shallow cuts. I think I will make a preliminary attempt with maybe 4 or 9 pyramids instead of the 36 or so in the original.

I will report back my progress as I go.

Thanks for the suggestions!

jjubenv
Posts: 46
Joined: Thu Dec 12, 2013 6:42 pm
Location: Ontario, Canada

Re: Need to establish workflow - help

Post by jjubenv » Sat Jul 25, 2015 4:07 pm

I may have found a problem with the Diamond/Circle/Square tutorial on the wiki http://www.shapeoko.com/wiki/index.php/ ... e/MakerCAM, but I'm not confident enough to change it as I'm not sure if I'm doing this wrong or not.

The CAM pocket operation for the square seems to have the fields copied from a profile operation instead of a pocket operation (It looks more like the settings for the 'profile' tool path instead of the 'circle' tool path).

Specifically, there is no 'inside/outside', for a pocket, the roughing clearance and step over are missing and the direction should be a 'Counter Clockwise' one. I just filled in the missing values from the 'circle' tool path, which were defaulted anyway.

Also, I think the 'profile' tool path should be an 'inside' one, unless the intent is actually to move 9mm deep into the side of the pocket, which I don't believe it is. Otherwise I guess it needs to have the stock surface height changed to 0 so the tool can start at the surface.

Unless I've done this tutorial wrong and don't really understand what I'm doing. (I just viewed my .NC file animation in OpenSCAM and it seemed to not do the right thing).

I can post my SVG with paths and NC if it helps.

EDIT: added comment about the profile operation from the tutorial.

WillAdams
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Re: Need to establish workflow - help

Post by WillAdams » Sat Jul 25, 2015 7:09 pm

Thanks. I’ll see what I can do to fix it.
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets

WillAdams
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Re: Need to establish workflow - help

Post by WillAdams » Sat Jul 25, 2015 7:41 pm

Good catch. I messed up on that. Should be fixed now. My apologies.
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets

jjubenv
Posts: 46
Joined: Thu Dec 12, 2013 6:42 pm
Location: Ontario, Canada

Re: Need to establish workflow - help

Post by jjubenv » Sun Jul 26, 2015 7:16 pm

Well, after a few failed attempts, I also learned that switching the profile to an inside one, also means that you must switch the direction to counter-clockwise.

I can fix this up on the wiki (I'll have to apply for an account), if some one agrees with the changes.

WillAdams
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Re: Need to establish workflow - help

Post by WillAdams » Sun Jul 26, 2015 8:33 pm

I’m not understanding why we would need to change the profile from outside to inside.
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets

jjubenv
Posts: 46
Joined: Thu Dec 12, 2013 6:42 pm
Location: Ontario, Canada

Re: Need to establish workflow - help

Post by jjubenv » Sun Jul 26, 2015 10:29 pm

From what I saw in the gcode simulator, the endmill just moved into the side of the bounding square (which is has been pocketed 'inside') at a height of -9mm + 1 , it didn't travel up to the surface before the move. I may have done something wrong.

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