bending an ellipse

[tangent dynamic]

I have a client who needs a router template made to pierce an elliptical hole through a flat piece of wood which will then be formed to the contour of a 12 foot sphere. Easy. The challange is he then wants me to machine a piece to fit the now bent ellipse.

 

Can anyone describe a way to bend an ellipse in Mastercam to a spherical contour. This cannot be achieved by just projecting the ellipse onto a sphere. Can this be done somehow by converting the ellipse to nurbs?

[Scott Reiner]

I think that a C-Hook called MAP is the ticket for what you want to do. In the C-Hooks directory check out the MAP.DOC file for info on how it works.

 

HTH

 

Scott

[Verisurf - Ernie Husted]

 

Yes, MAP.DLL is half the tool you will need to accomplish this. First you will need to flatten the sphere surface using the FLATSRF.DLL then project an ellipse onto the flattened surface, make sure you set the option to save a surface curve so that you can use the MAP chook. After you map the surface curve from the flatten surface to the sphere surface you will need to figure out a way to turn that surface curve into a NURBS or Parametric spline. At one time there was a chook to convert surface curves to Parametric splines but I think Pete lost it.

 

If you need more help let me know? this is the fun stuff.

 

Ernie

 

[ 01-18-2003, 12:40 AM: Message edited by: Tri-Tech 5-axis ]

[Fig sign]

quote:

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At one time there was a chook to convert surface curves to Parametric splines but I think Pete lost it.

 

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It is CON2SPL.DLL.

If you don`t have it I can put it on ftp

[Verisurf - Ernie Husted]

quote:

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It is CON2SPL.DLL.

If you don`t have it I can put it on ftp

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That's it, sorry Pete, I forgot the name of it. I do have it.

 

Thank you Iskander for jogging my memory.

 

Ernie

[Scott Bond]

Welcome to the Forum Adam.

 

Tri-Tech 5-axis , That was a Great post. I learned

once again that the old antique way that I work with my surfaces has been improved on.

[gstephens]

Also, just for further info. If you convert a model with surfaces,surface curves, or splines to a VDA file, then convert it back in, ALL of the entities come in as parametric surfaces/splines.

[tangent dynamic]

Thanks very much for all your replies. I have not had a chance to try Map.dll yet but it looks like it should work great. Hey, Ernie@ Tri Tech 5 how did you insert the graphics into your post...pretty cool.

 

Adam.

[LastCat]

Wow,,you guys are way over my head. I'll get there one day.

 

Nice work.

 

still wearing baby shoes

Lastcat

[Richie21]

Yes, amazing what you guys can do with this modern software. I did such milling once, using a 5 axis gantry with a turntable, six axis moving simultaneously. As for the math, I haven't got the foggiest idea even though I know basics of calculus. They used to hire specialists.

 

My question is, machining this ellipse, can you do it on a 5-axis machine ?

 

Richard

[John Summers]

Tangent,

The flat piece of wood which will be bent into a sphere may not bend the same way FLATSRF is going to bend it. The 3d surface, then, should reflect what the wood will do, which is bend into a cylinder.

FYI, FLATSRF first flattens down the center (the spine), then flattens the 'ribs', curves perpendicular to the 'spine'. All the curves end up in their true length. It's important to choose the 'spine' direction correctly.