Fairly new at CNC Machining. Dimensions of the .dxf are a probleme

Hi guys,

I’ve cut the Sled for maslow using the file provided and put it in makercam to generate the gcode. When I’ve cut it no trouble whatsoever, the dimension were alright, everything was the correct shape (a perfect disk! ).
But now, I’d like to cut the Edie Set from opendesk. All they have is a .dxf, not a svg. There is no problem with that, but when I put it in MakerCam (after the convertio step), I am not able to have the furniture at the correct size (it is right now at a enormous 1 inch of size…).
So after a few calculations and modifications of the scale of the pieces, I have the correct size. Now that I think I am ready to create the pocket and profile operations, some pieces (the seat part actually) are not taking in account during the calculation of the cut, even if they are properly selected and the profile set.
Did anyone add the same issues? Is it a rookie mistake?
PS : I have the same kind of scale and profile operations issues in Fusion360.

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Hi there, can’t help with makercam or F360, but you have enough friends here to jump in.
What I know is, that can’t just go from download to cut.
Even if the file is for (example) 18mm ply, if you buy 18mm ply that could be between ~20mm and ~16mm depending on Florida or Texas. :slight_smile: Humidity.
You would need a CAD program to adjust the pockets for other to parts to fit in according to your material.
Scaling can also happen there. (draw a reference part of known length to be sure scaling is right)
Also used to move parts around for more efficiently using the sheet.

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I usually use Inkscape to do my file conversions because of scaling issues with convertio so that’s the first place I would start.

The second half of this youtube video will show you the process I use:

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Thank you guys I’ll check that out.

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That sounds like the dxf was saved in inches, but you are loading it in mm.

It’s a very common problem and hits experienced people regularly (they just have
hit it enough to recognize the problem quickly)

I thought so too, I might even still be the case …but I have verified that my units of measurement on Fusion360 and the dxf’s are in inches and it doesn’t work either. This is why I am a bit puzzled…
I’ve also tried with the dxf of another source and I have the same issue.
I’ve just finished testing Bar’s solution with Inkscape depending on the dxf the rendering seems to vary. We can’t open the opendesk dxf for the Edie set no idea why and we’ve tried several dxf and it seems to work but the measurement are always off even with the right unit selected.
I’ll try some more but basically even if the dxf is on a 1:1 scale in inches or millimeters, it is impossible for me to get a rendering of the correct size right away on any software (Fusion360, Inkscape, MakerCam) without a good tweaking of all the parameters. It is odd because it seems that few people have that kind of problem, and I put that on my non-experience of the cnc Workflow.
Do you have tricks that can speed up that workflow?
In any case, a big thank you to Bar and you guys for your quick answers.

Those open desk files are cluttered and bulky with many layers. You will need to adjust the drawings in CAD to the material thickness you will be cutting. I believe open desk parts are drawn to about 1 inch thickness and if you cut without adjusting - your parts will not fit.

I thought so too, I might even still be the case …but I have verified that
my units of measurement on Fusion360 and the dxf’s are in inches and it
doesn’t work either. This is why I am a bit puzzled…

The fact that they are in inches is the problem

dxf doesn’t store any info as to what unit the numbers are in, it just stores
the numbers.

so if you CAM software (makercam) assumes that the numbers in dxf files are mm,
and the CAD software is exporting inches, you are off by a factor of 25.4x

in your cad software, export the files to dxf in mm, not inches.

I’ve just finished testing Bar’s solution with Inkscape depending on the dxf
the rendering seems to vary. We can’t open the opendesk dxf for the Edie set
no idea why and we’ve tried several dxf and it seems to work but the
measurement are always off even with the right unit selected.

you are trying to open the files in what software?

I’ll try some more but basically even if the dxf is on a 1:1 scale in inches
or millimeters, it is impossible for me to get a rendering of the correct size
right away on any software (Fusion360, Inkscape, MakerCam) without a good
tweaking of all the parameters. It is odd because it seems that few people
have that kind of problem, and I put that on my non-experience of the cnc
Workflow.

Do you have tricks that can speed up that workflow?

don’t use so many tools. inkscape and makercam are nice simple tools to get
started with, but doing work in a real CAD program and then running it through
inkscape to get to makercam is going around the block to get next door.

If you use Fusion 360, use it’s built-in CAM capability to create the g-code for
the maslow directly.