Trouble with Ellipse and arcs

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wdm
Posts: 13
Joined: Sat Jul 12, 2008 6:19 am

Trouble with Ellipse and arcs

Post by wdm »

I am engraving on phonelic material. I have a logo with arc's and ellipses in it. When machining out, the ellipses are not smooth. I am using vectors which are from an ACAD R2000, VCP 4. In the preview, they appear to be smooth.
Thanks in advance
Doug

James E
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Location: Derbyshire UK

Re: Trouble with Ellipse and arcs

Post by James E »

Hi Doug.
One thing about the previews...They are really accurate. That means its the machine software or hardware, I think.
Some faults like this have been seen by users of Mach 2 or 3, where the cv setting has been incorrect for the type of cutting.
Another time it was the nature of the file, .eps, exported from Corel I think. When looked at closely it was actually many short straight lines not quite touching.
Alternatively, has your machine been working well up to this file, and can you cut a simple circle and square nicely? If yes, it's back to the file for a really close look at the vectors.

Can you describe the 'not smooth' in a different way?

Jim e
The only thing you enjoy is moaning about how #%*t your life is! Well you can pack that in!

wdm
Posts: 13
Joined: Sat Jul 12, 2008 6:19 am

Re: Trouble with Ellipse and arcs

Post by wdm »

James
I forgot about the sections of an arc being straight lines. I will check that for a solution. The best way to describe the jagged edges would be if you took a bite out of the moon when it was in its quarter state.
I am working with a logo that is approx 1.25 wide x 1 high. Using a Straight bit with .012 diameter, cutting depth is .015. I tried a 30 degree with .02 flat but it was even worse. Besides the logos there is a large amount of text (.1 - .375 in height)
I will check the arcs's and try different speeds to see if that makes a difference.
Thanks again
Doug

tmerrill
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Re: Trouble with Ellipse and arcs

Post by tmerrill »

Doug,

One thing you can try is to select the vector and go into node editing. If you see many boxes, this may lead to a rough curve. If you see this, try using the Edit - Curve Fit Vectors tool to see if you can clean it up.

Another option would be to start another layer and trace over the vector. Then use the new vector for your toolpath.

Jim is correct about the preview - if it looks good, most likely its mechanical.

Tim

ger21
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Re: Trouble with Ellipse and arcs

Post by ger21 »

In AutoCAD, before drawing your Ellipse, set PELLIPSE to 1. This will give you an ellipse made up of arcs, and may give better results.
Gerry - http://www.thecncwoodworker.com

gravirozo
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Re: Trouble with Ellipse and arcs

Post by gravirozo »

hello


gerry, shame on me... i never know this feature... :oops:

i always draw over a quarter of ellipse with polyline, w snap nea....


thanks for idea....

viktor

wdm
Posts: 13
Joined: Sat Jul 12, 2008 6:19 am

Re: Trouble with Ellipse and arcs

Post by wdm »

I've been playing in ACAD since 1990 and never new that setvar. Tried it and blew my mine. I/we have always had trouble with ellipses and exporting them. This will change that now.
I have not had a chance to try the other solutions posted but will do in on Saturday. I appreciated all the responses and all the assistance.

Thanks
Doug

gravirozo
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Re: Trouble with Ellipse and arcs

Post by gravirozo »

and who knows how many surprise in acad yet... :-)
and the worst, you just can't explode that mean ellipse :-)

wdm
Posts: 13
Joined: Sat Jul 12, 2008 6:19 am

Re: Trouble with Ellipse and arcs

Post by wdm »

I was finally able to try some of the suggestions regarding the ellipse's. The winner is James. The problem was hardware related and not software related. Made a few adjustments and the arc'/ellipse's are true. I would like to thank all who supplied suggestions.

Thanks
Doug

James E
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Re: Trouble with Ellipse and arcs

Post by James E »

YAHAAAAY :lol: :lol:
My extensive experience of wobbly machinery you see....
But seriously. Thanks for posting the resolution to the problem.
When I do a search with a symptom, find a thread about it, and the thread just peters out with no 'This was the cure' at the end, it helps, but it would be more helpful if the cure was posted; this is where I would start.

Jim
The only thing you enjoy is moaning about how #%*t your life is! Well you can pack that in!

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