Problem cutting elipse

[robert_cheal]

Every now and again I have to cut molding profiles, I manually construct a tool path with various cutters to achieve results similar to Bill Young's Extruder. One problem, I use Vector and I would need Parts Wizard to utilize Bill's program. For example at present I am getting ready to start a mold for a 5'x9' trim for an oval dome using 5 different cutters. It's not too bad doing this in AutoCad, then importing to Vector to get the .sbp file.

Part of the problem is that the ellispe cutting paths developed in AutoCad turn into splined representations once imported as .dxf into Vector. When it goes to the ShopBot to cut the file it is reading tiny little straight line segments to create the ellispe. But the real problem is that several times while cutting it pauses, cuts a little circle, then continues until it decides to repeat the little circle again. I once read about this type of problem on this forum but I can't find it again. I wondering it it is a setting on the SB software or if I need to create the ellispes in Vector which can create an elispe with spline or a series of arcs. The big draw back is that Vector 9 is tedious as a drawing program. I am currently using the latest software that came with my G4 upgrade.

Any advice would be appreciated.

Thanks, Robert

[gwilson]

Have you tried the poly ellipse in Autocad. It is a variable setting. Type pellipse in command line and change the value to 1. The waterjet I have at work does not process normal ellipses, but uses poly ellipses fine.

Hope this helps

[bill.young]

Hi Robert,

Here's some info on the tiny circle problem in Vector.

http://www.talkshopbot.com/forum/messages/31/1744.html

[robert_cheal]

Gerald & Bill,
Thank you for the help. After checking each of your suggestions out I can now redraw my work in AutoCad with the the (pellipse set at 1) or in Vector I can also select each ellipse and change the spline properties. I changed the the unit value in Vector from 4 to 6 as recommended that might take care of the problem. I have Vector 9.0 not Vector 9.3 which can backplot code and check for loops. I will lose some time but the great news is that I can fix this before messing up while cutting. In the future I will be more aware before I start drawing.

Thanks again,

Robert

[robert_cheal]

I don't know if this is of any interest to anyone but here are the belated results of the project that started this thread.

4501

I ended up drawing the individual
tool path for each cut in AutoCAD.

As stated above the AutoCad elipse is very short segments of straight lines when it is imported into Vector. I had cut smaller elipse moldings before but this project had enough volume (cut with multiple router bits ) to freeze up Vector so I had to break up each router bit into it's own file. Then Vector could handle it I was also able to re-define each elipse with Vector and convert it in what ended up being a series of arcs with some small straight line segment transitions between the larger arcs. This made the files much smaller and easier to work with.

One note of interest: when I did the Pelipse command in AutoCad it certainly did convert the elipse into arcs but it was not a true elipse and did not match prior parts already cut for this project so I had to go a different route.


4502
This is a the profile photo of the molding and believe it or not it represents several revisions to get an accurate profile and approval of the customers drawing. Once the molding was detailed out a mold was made from it to cast the the final trim for a 5'x 9' fiberglass ceiling dome.

My question is how to go about this again the next time a similar project come up. My present situation is AutoCad to Vector to ShopBot. Should I invest $500 in PW or Vectric software?

Robert