Cam pocket on cylinder face

I'm trying to figure out how to cut a elliptical shaped cam follower pocket onto a cylinder face. The cylinder will be rotating and the pocket in the side of the cylinder needs to drive a cam follower back and forth. The cam path only needs to be cut around the axis of the cylinder about 90 degrees. The sides of the pocket have to be parallel and perpendicular to the outside surface as if a end mill cut it while the cylinder rotated on it's axis.

I project a sketch onto the surface and try and sweep a cut or loft a cut, but I can't get the sides to stay square and parallel even with multiple guide curves.



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Take the sketch that you made and offset it so you have 2 paralell projected curves one representing the path the other will be a guide curve. Make a sweep using one guide curve.

I just tried it and it worked well.

regards, Corey Scheich

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Corey Scheich

I just did this using sheet metal functionality. You extrude a cylider, flatten it, cut in the cam in the flatten and roll it back up.

There may be some glitch> I'm trying to figure out how to cut a elliptical shaped cam follower > pocket

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On the SW website they have a example of this. I don't believe the geometry is quite right on the side walls.

They also have another example using a helix that looks nice, but not what I need to do.

Still haven't got anything to work yet.


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Not sure I understand (confused by the "elliptical".... no, just normally confused), but if it is an end mill slot cut around a cylinder (I don't use SW, so am unsure of the methods used to create the geometry) ......

If you start with a surface that represents the path of the cutter axis and offset by cutter radius or thicken by cutter diameter I believe that the results should be the slot faces. The surface could be created by ....

1) Lofting between the cylinder axis and a curve wrapped on the cylinder face (or sweep a line between the two curves),

2) wrapping the curve to cylinder face, offsetting normal to surface to a different radius and lofting between the two curves (or just create two helical curves if that's the desired path),

3) for partial turns around the cylinder loft between two cylinder radial lines that represent the slot ends,

...... etc.

The end result should be a surface that if intersected with a cylinder axis radial or axis normal plane creates a line that will be the cutter axis at that point. (I don't know the solution is correct, but it appears to work. ???)


If I might ask a question of the CNC savvy out there: What information would most readily facilitate doing the setup? Verbal / written description, curve on cylinder surface, a surface describing the cutter axis path or just use the finished solid model (assuming it's a good representation)? Does it really matter or "none of the above"?


Reply to
Jeff Howard

Jay I believe this type of issue was covered recently here under an o-ring query. if you like I could send you what I think is a geometrically correct example for the side walls I did at the time for my own interest that may help you -600k zipped-(SW2003). you will need to send me an address as I don't have any way to post this for the group. cheers

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Jay and I had some corespondence today outside the Group I am posting it incase anyone is interested ______________________________________________ Corey,

Thanks for trying this and giving me a explanation.

I have attempted it a number of different ways as you describe and still

can't get it to work the way I need.

Any chance you could send me a part file of what you did for a look?

This is bugging the heck out me.




Here you go Let me know if it isn't what you were looking for

Cut" Make your reference plane Normal to the curve and select one endpoint.



Thanks much for your time helping me with this! I don't have time now, but

maybe tonight I can try your ideas.

Thanks again.


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Corey Scheich

Yes! Here is the link...

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Somewhere in there you can find some examples.

Mike Wilson

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Mike J. Wilson

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