MakerCan > Shapeoko3 units and sizing problem

DannyBoyNYC
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MakerCan > Shapeoko3 units and sizing problem

Post by DannyBoyNYC » Sun Jul 26, 2015 7:33 pm

Hi all. I'm relatively new to this so bear with me.

I have finished construction and am putting my Shapeoko 3 through its paces by trying to cut a simple 6" x 1" square out of plywood.

My workflow is Illustrator > Inkscape > MakerCam > Carbide Motion with a .25" bit.
My settings are factory default (verified in Carbide Motion's terminal window and against those posted to the wiki).
My problem is getting the cutout to measure 6" x 1". It is always over or under.
I use inches for measurement in Illustrator and then process and recheck in Inkscape and I have tried the following in MakerCam:
Cut #1 - Makercam - settings in inches
Cut #2 - Makercam - settings in mm
Cut #3 - Makercam - set the prefs to 90
Image
My profile settings are:
Image

I'm pretty certain this has been covered before but cannot find the post. Can anyone tell me what I am doing wrong?

Thanks!

WillAdams
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Re: MakerCan > Shapeoko3 units and sizing problem

Post by WillAdams » Sun Jul 26, 2015 8:30 pm

Inkscape 0.91?

I suspect that you’re encountering the new 96ppi sizing which it implements.

Obviously time for some experimentation.
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets

DannyBoyNYC
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Location: Brooklyn

Re: MakerCan > Shapeoko3 units and sizing problem

Post by DannyBoyNYC » Sun Jul 26, 2015 9:48 pm

Thanks Will.

I find it odd that screen measurements (pixels per inch) have any impact on the output. e.g. When I design a 6 x 1 inch square and print to a 8.5x11 sheet of paper they don't factor in at all!

I guess this technology is not quite as mature as desktop publishing ;) or web design for that matter.

So do I change the stepper settings in the GRBL defaults or just resize everything to a specific percentage in Illustrator?

I've been trying to use another program to see if the issue is with Makercam but the last time I tried MeshCAM the Shapeoko drilled straight through my waste board (and probably would have kept on going if I hadn't aborted). I've since learned to use openScam to visualize the cut before pressing the start button!

I'm on a Mac so my options appear to be limited in terms of software.

WillAdams
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Re: MakerCan > Shapeoko3 units and sizing problem

Post by WillAdams » Sun Jul 26, 2015 10:46 pm

SVG is a screen-oriented format.

Adobe Illustrator uses 72 ppi
Inkscape v0.91 90ppi (while there was some discussion about changing this, it seems to not be 96ppi)

a 1 inch square from Inkscape 0.91 r13725:

Code: Select all

   <rect
       style="fill:#ffff00"
       id="rect3336"
       width="90"
       height="90"
       x="0"
       y="962.36218" />
My suggestion would be to test any workflow w/ an object of known dimensions.

The only tweak necessary should be setting http://www.shapeoko.com/wiki/index.php/ ... references
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets

WillAdams
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Re: MakerCan > Shapeoko3 units and sizing problem

Post by WillAdams » Mon Jul 27, 2015 3:31 pm

Apparently the change to 96ppi is in Inkscape's experimental branch and will be done for v0.92: http://bazaar.launchpad.net/~inkscape.d ... sion/13380
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets

BellyUpFish
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Re: MakerCan > Shapeoko3 units and sizing problem

Post by BellyUpFish » Mon Jul 27, 2015 3:51 pm

That explains some things for me, maybe.

I'm still chasing size issues, but haven't really had a chance to run too many tests.

I ran a square-diamond-circle test someone posted here and all my measurements were larger than the test files should have been, but they were at least close to uniformally larger.

I think I'm at 40.65 on X and Y, haven't tweaked Z yet and I'm not sure 40.65 is going to work, it's just where I had to take it to get a file I needed cut, to the right size. I had to tweak both the CAD file and the Grbl settings...

I plan on going back to 40.020 this coming week when I have some time to play and see what happens.

WillAdams
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Re: MakerCan > Shapeoko3 units and sizing problem

Post by WillAdams » Mon Jul 27, 2015 4:32 pm

My suggestion would be to take variables out of the equation.

Set your steps back to 40 (to make the math easier), then drill a set of three holes equidistant along a right angle, just a bit less distant from each other than the longest distance your most precise measuring tool can measure, then measure the distance between edges: http://docs.carbide3d.com/article/42-ho ... lt-stretch

Once you've done that, there's a hand-coded file on the wiki: http://www.shapeoko.com/wiki/index.php/ ... quare_Test

Cut that and use it to determine runout for that endmill in that material.
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets

BellyUpFish
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Re: MakerCan > Shapeoko3 units and sizing problem

Post by BellyUpFish » Mon Jul 27, 2015 4:44 pm

I think you're right, Will. That's what I plan on doing.

Should I go back to 40 even or 40.020?

Please forgive my noob questions, how do I use the text file in the wiki into something cutable?

WillAdams
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Re: MakerCan > Shapeoko3 units and sizing problem

Post by WillAdams » Mon Jul 27, 2015 6:02 pm

40.000

The G-code file on the wiki is ready to send (albeit set to really slow speeds for HDPE on a Shapeoko 1). If your comm/control program doesn't see it, change the file extension to something it will accept.
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets

BellyUpFish
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Re: MakerCan > Shapeoko3 units and sizing problem

Post by BellyUpFish » Mon Jul 27, 2015 6:11 pm

Ok, I'll set it to 40.00 and see where I get.

I really appreciate your help, Will.

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