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Globoidal CAM in OpenSCAD

Posted by yngndrw 
Globoidal CAM in OpenSCAD
April 01, 2012 03:25PM

I am trying to make a parametric Globoidal CAM model in OpenSCAD but I've become a little stick on how to make it. My initial idea was to make a profile of the turret (Output wheel), extrude / twist it to make a model which represents the path of the turret, then difference this from a cylinder to make the cam.

Attached is what I have so far. (GloboidalCAM.scad)

My problem is that there's no way to add a twist in the rotate_extrude() command. Any ideas on how I can do this ?

Here is a Globoidal CAM if anybody is wondering: (Although I want a continuous one, not an indexing one with the dwell section - Ideas on how to add it with the dwell would also be welcome, though)

I also think that a pair of bearings should be used for each spoke of the turret, but that's easy once I get this twist problem sorted.


Edited 1 time(s). Last edit at 04/01/2012 03:39PM by yngndrw.
Re: Globoidal CAM in OpenSCAD
April 01, 2012 09:59PM
What you are describing would be called a sweep in SolidWorks, and maybe other systems. However, if you are planning to do this with a 2d profile, it won't work. Modeling cams is a subject that turns up from time to time in CAD forums because sweeping the 2d profile will not result in the same shape the end mill or your cam follower will follow.

What you need to do is create a multitude of copies of your cam follower, each twisted appropriately for its position. Difference those copies from your cam. Solidworks has a function for the kind of feature you are trying to make ("solid sweep"), and what I have described is how the function basically works under the hood.

Edited 2 time(s). Last edit at 04/01/2012 10:05PM by Dale Dunn.
Re: Globoidal CAM in OpenSCAD
April 02, 2012 07:38AM
Thanks I'll try that tonight.
Re: Globoidal CAM in OpenSCAD
July 10, 2012 04:32PM
Can any buddy help me to globoidal cam animation and 3 curve generation

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