my circles arent circles

my circles arent circles

Postby thephridge » Thu Apr 05, 2018 11:37 pm

I draw a circle in here and transfer over to mach4 and run the operation and it dose not cut a perfect circle!? sorry we are noobs over here so this may sound dumb. Any help would be awesome
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Re: my circles arent circles

Postby Mike-S » Thu Apr 05, 2018 11:52 pm

Did you calibrate X & Y? If you profile "on" a 5" x 5" square with a shallow cut V-bit, does it measure 5x5?
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Re: my circles arent circles

Postby thephridge » Thu Apr 05, 2018 11:56 pm

We calibrated using the mach 4 built in system. We had good luck initially but something has changed somewhere. We tightened all mechanical adjustments so we're good there. Can you expand on "on"? LOL.
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Re: my circles arent circles

Postby Mike-S » Fri Apr 06, 2018 1:12 am

Profile cuts can be "on," "inside," or "outside" the vector. I'd still try a square of known size to see if you get a true square.
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Re: my circles arent circles

Postby IslaWW » Fri Apr 06, 2018 1:17 am

If your machine has been calibrated properly and your preview looks as you would expect, this is most assuredly a machine issue. Try cutting the file at half the feedrate and see if the results get better
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Re: my circles arent circles

Postby thephridge » Fri Apr 06, 2018 1:30 am

Thanks Mike. Gary...the previews look a little out of shape to me. Thats just making an ellipse and making it vector. It appears to have slight variations in the curve here and there. I thought there might be a setting that would smooth it out.
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Re: my circles arent circles

Postby thephridge » Fri Apr 06, 2018 1:31 am

And we slowed the feed rate way down.
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Re: my circles arent circles

Postby martin54 » Fri Apr 06, 2018 8:17 am

is this a circle you have drawn yourself using the software or one that has been auto traced as part of something else?
If you enter node edit mode how many nodes does your circle have? :lol:

If you post the file then someone will check it for you :lol:
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Re: my circles arent circles

Postby thephridge » Fri Apr 06, 2018 1:17 pm

here is just the circle usually we cut multiple at one time, our goal is to cut a 4by4 sheet of circles at one time. we keep getting indents and other imperfections in the circle same on every single one. usually it shows up where the tabs are, i have ran the machine in the step calculator in mach 4 and the machine is running perfect if i tell it to move so many inches it moves exactly that, on every axis :roll:
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3inch circle.crv
(19 KiB) Downloaded 85 times
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Re: my circles arent circles

Postby IslaWW » Fri Apr 06, 2018 1:40 pm

If you are getting deflection in the tab locations, this is for sure an issue with the machines rigidity. There will always be a reduction of edge quality when the z axis moves vertically, but it should be minimal.

Check for something loose in the axes. If nothing is loose, then you may simply be bending something
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Re: my circles arent circles

Postby thephridge » Fri Apr 06, 2018 2:06 pm

here is another file is just tried cutting again checked my machine its tight no sloppy play in it at all. we also removed the vacuum hose to reduce any kind of variable and still have the same issue.
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3 inch circle.crv
(160 KiB) Downloaded 86 times
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Re: my circles arent circles

Postby IslaWW » Fri Apr 06, 2018 2:28 pm

There is nothing wrong with the file. Post a picture of the results
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Re: my circles arent circles

Postby Adrian » Fri Apr 06, 2018 2:33 pm

It is 100% not the software. Think about it. If it was the software there would be hundreds of people posting here with the same issue if there was something that fundamentally wrong with the software.

Try reducing your pass depth or ramping into the cut. 0.3" in one go with a 1/8" bit might be too much. I certainly wouldn't cut that deep in one pass without a ramp in anything but the softest materials with a bit that small. It's almost certainly deflecting.
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Re: my circles arent circles

Postby thephridge » Fri Apr 06, 2018 3:15 pm

this is one we just cut with a ramp in and slower feed rate and set to not cut as deep still same issue with tabs
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20180406_100639_resized_1.jpg
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Re: my circles arent circles

Postby Leo » Fri Apr 06, 2018 3:31 pm

Whatever is wrong - it IS absolutely IN the machine - NOT - the program.

There are only 4 nodes on the circle and the program CANNOT generate the effects you have in the picture.

There is something going on in the machine. Looks like uneven forces causing deflection.

A machine cannot be called rigid by virtue of shaking it with a hand, and it "feels" good.

You need to measure it at many different points with an indicator to measure the movement - possible with a fish scale or something similar to measure force applied and indicator to measure movement and any given force.
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