Modeling a circular cam cut on a rotational axis

[EricBaisch]

I need to ask for advice in modeling a circularcam. We cut circular cams mounted on a rotational axis with an end mill located radially to the axis of rotation fo the cam. Our Pro/E models for the cam surfaces are created flat and then rotated 360 degrees with a toroidal blend. These are close to what the machine cuts but not exact. The cam surface of the models becomes conical, intersecting the center of the part, instead of being cylindrical, offset from the center by the tool radius. I need exact models for a project I am working on to have these cams made from powdered metal.

Does anyone have any ideas about the best way to model these in Pro/E?

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[jeff4136]

I'm not certain, from the description (circular? cylindrical?),
the attached represents what you're doing. If it does; accurate
representations of the groove side surfaces are not a problem,
groove bottom surfs can't (?*) be accurately modeled in Pro/E
but if fair approximations are good enough the attached is
quick-n-easy.

* Topic: How to model 4th axis milling cut
http://www.mcadcentral.com/proe/forum/forum_posts.asp?TID=36813
(culminating with ...)
Topic: Modeling - 4 axis end mill cut
http://portal.ptcuser.org/p/fo/st/topic=3&post=63323#p63323

[EricBaisch]

Thanks for everyone that contacted me with possible solutions for this. Although it was not the correct solutionfor us Ron Rich got us going in the right direction with his model using the "wrap" feature. This is whatone of my guyscame up with.

-Model the cam"blank"

-Sketch the cutting tool center line in the flattened state (2-D to be wrapped around a cylinder).

-Use the wrap surface feature to revolve the tool path centerline around a cylinder.

-Use "project" to radially offset the wrapped tool path. We projected to surfaces inside and outside the finished cam surface bounds because the "thicken" command used later created some strange surfaces very close to the cam edges)

-Select the two radially offset wrappedtool centerlinesand use "boundry blend" with the fit set to "piece to piece" to create a surface representing the path of the tool centerline.

-Use "thicken" to offset the tool centerline surface by the tool radius.

For clarification have a look at the attached picture and shaded part image.

Eric