Designing a Snail Drop CAM

[YPatrick]

Hey Everyone,

I'm noticing a lot more FRC teams have been using snail cams for shooters and other continually reloading mechanisms, but I can't think of any ways of making a progressive CAM in CAD. Any ideas? I'm talking about these:
http://www.technologystudent.com/images5/snlcam3.gif

[Ether]

Originally Posted by YPatrick

I can't think of any ways of making a progressive CAM in CAD. Any ideas?

You can create spirals easily using polar coordinates.

See attached examples.

Also check out these threads:

http://www.chiefdelphi.com/forums/sh...93#post1330693

http://www.chiefdelphi.com/forums/sh...40#post1326440


One nice feature of a cam is that, with a little math, you can derive the equation (or generate a lookup table from experimental data) so that the torque required to drive it remains constant as it is pulling back the arm. Then you can use that equation to cut out the cam.

[YPatrick]

Originally Posted by Ether

You can create spirals easily using polar coordinates.

See attached examples.

Also check out these threads:

http://www.chiefdelphi.com/forums/sh...93#post1330693

http://www.chiefdelphi.com/forums/sh...40#post1326440


One nice feature of a cam is that, with a little math, you can derive the equation (or generate a lookup table from experimental data) so that the torque required to drive it remains constant as it is pulling back the arm. Then you can use that equation to cut out the cam.

Thanks, I'm trying this in my CAD software right now.

[evand4567]

You might be able to do it using the Design Accelerator in Inventor. If not, you can create the function and plot it in a sketch.

[DonRotolo]

I've created a cam in Excel and exported it to my CNC program for cutting.
As Ether mentioned, the goal was fairly constant torque on the motor turning the cam.