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Help getting correct measurements on cuts


#1

When I have a test pocket cut of 20mmx20mm pocket/fill cut and an outside cut of 40mmx40mm I get 3-4mm short in each direction. my 20x20 is around 16x16 to 18x18, havent hit 20 yet. my 40mm square is 36x36 or something like that. I have run calibration as many times as I’ve tested… ~9-10. I have remeasured the other settings and run again. I have done some at ridiculously low speeds (150mm/min) and insanely fast for maslow (750) something that remains constant is cuts being short. I have a 1/4" bit and I put 6.35 in for it every time. I have included my GCode file as well. not sure what else to do at this point. if someone else could run the gcode to compare it would be much appreciated, maybe that’s a big part of the issue? Not sure where to go to now. My last calibration and test did worse than before.

test (2).nc (5.0 KB)

Image included just as an illustration of how many times I’ve been trying to work through this. I have things generally working well but if Im going to move on from cutting generic signs and get to things where pieces fit together then measurements matter.

thanks in advance.


Intelligent positioning?
#2

@Jay_Settle is in the same boat. Maybe he can try your gcode.

Have you tried @Joshua ‘s holey calibration? Have you gone through the List of sources of error thread?

Right now in the sweet spot im getting ~0” - 1/4” error. I’m still working through the variables.


#4

yes Ive gone through the list. I’m not familiar with Joshua Holey Calibration


#5

This may be relevant:

bar

May '18

I think I know what’s going on. The issue has to do with the default resolution of MakerCAM not matching the resolution of the file saved from inkscape. Changing the import resolution to 96 in MakerCAM fixed the issue for me.

I’ve created a pull request here to propose updating the file resolution to import into MakerCAM the correct size.

This earlier sled design is actually a little smaller than the new 18 inch sled (I think it’s 400mm?) so don’t be concerned if it comes out a little smaller.
I hope the above paste is a link for you to check out.


#6

So let’s go through it. What are you using to CAD? What are you using to CAM? What OS are you on?

Thank you


#7

CAD: Easel
CAM: Ground Control
OS: OSX


#8

Unfortunately GC is not CAM as it does not produce g-code. I have not used Easel, but my understanding is that it is CAD/CAM. The fact that you are getting squares and not rectangles speaks to a scaling issue and not a calibration issue. I think @TheMerryYeoman’s suggestion has merit.


#9

ok, you got me… I generated the gcode in Easel. I attached it to this post as well. I also generated gcode in easel for an xcarve and it came out perfect, no scaling issues. I can try the scaling adjustment, but really don’t think it’s addressing the issue and if Im correct will manifest in issues in other ways.

I might get etslcam just because it’s supposed to be nice for planning paths etc. I can also try cutting the large calibration pattern in ground control.


#10

I ran through the first segment of g-code, and you are correct, it is certainly specifying a 20x20 mm square cut if you are using a 1/4" bit. I’d be happy to take a look at it on my machine, but I probably wouldn’t be able to get to it until the weekend.


#11

thanks a lot, Im in no rush


#12

I guess you didnt have time to mess with it?


#13

Hi Anthony. No, sorry, I completely forgot to run your code. Sorry about that. I will get back to you once I’ve had a chance to play with it.