Elipse

[Eric S.]

Hello

 

I Have Geometey of am elipse that is made up of a bunch of straight lines. problem is when I machine the contour it get all these facets. I have tried messing around with the filter nothing seems to work? Is there a way to convert the lines to arcs or break the lines up smaller and smooth the toolpath so I do not get the flats?

 

Thank you

 

Eric

[jrykrl]

Modify, Break, spltoarc.

Jer

[Eric S.]

hi

 

thanks for the response but I belive the spine has already been broken into lines? Is there a way to reverse this?

[jrykrl]

I used create-ellipse,

then modify-break spltoarc and it worked

Several small arcs, but should work if your control reads ahead.

Jer

[James H]

Hi

 

Have you tried to increase the linearization tolerance for your tool path. This will increase the number of points that the tool will follow.

 

 

James

[Eric S.]

I have tried to increase the linearization tolerance for the tool path. It made no difference.

[James H]

Do you have enough data to reconstruct the elipse using MasterCam? You could create a spline from the end points of the lines, this could be a major pain. It would produce the results that you are looking for.

 

You could try to add a radius between the lines to smooth it out.

 

[ 12-06-2003, 07:35 PM: Message edited by: rcracer ]

[Rick Damiani]

quote:

---

Have you tried to increase the linearization tolerance for your tool path. This will increase the number of points that the tool will follow.

---

I beleve that the way to generate more points is to reduce the linerazation tolerance. Making the linerazation tolerance larger would generate fewer lines and produce more noticeable facets.

[Rick Damiani]

quote:

---

thanks for the response but I belive the spine has already been broken into lines? Is there a way to reverse this?

---

Not completly. You can, however, generate a new spline using the broken elipse as the source. Select Create|Spline|Curves and chain the line segments that make up the elipse. Note that the default tolerance for this is set to .001.

 

After you have the elipse converted to a spline, you can either Modify|Break|Splines to Arcs to get the spline converted into arc segments, or you can filter the toolpath. Depending on the size of the resulting arcs, you might also want to check your post to see if arccheck is turned on. If it is, check the atol and ltol values.

[PBpaul]

This may or may not help but it reminded me of a similar problem we used to have. Is there any chance the original ellipse was created in Autocad? We had the same facet problem trying to machine those but found that if the ellipse was exploded before export, then it cut fine.

PBPaul

[Eric S.]

Hello

 

Thanks guy's for you help.

Last night I ended up cheeting and filleting all the lines this helped a bit. Rick It soulds loike your method is what I am looking for I'll give it a try thank you very much!

 

Eric

[Rick Damiani]

quote:

---

This may or may not help but it reminded me of a similar problem we used to have. Is there any chance the original ellipse was created in Autocad? We had the same facet problem trying to machine those but found that if the ellipse was exploded before export, then it cut fine.

---

AutoCAD ellipses from AutoCAD R13 and later can only be exploded if PELLIPSE is set to 1 to force the creation of polyline ellipses. Ellipses have been native AutoCAD objects since R13.

[Pierre Côté]

Creating an ellipse with the rectangle option will give you an ellipse with lines only.

 

Myself, I never use this type of ellipse construction.

 

Always use the ellipse creation.

Create

Next menu

Ellipse

 

Do not forget to :

Modify

Break

Spl2arcs

 

 

This will give you all tangent arcs.