Hi BG, thanks the image helps a lot. So yes you do really want to cut a helix on your CNC!
MoI would be very well suited for making the 3D model for that, There's only a few steps really, I don't think you'd gain anything from parametrics in this case. It's simple enough that you could just draw a new one in a few minutes if you wanted to change something.
It's probably all the details that will be involved with the CAM and CNC that will probably be quite difficult.
Maybe it could be easier if you worked with a dedicated CNC lathe rather than an additional indexer?
It also seems like it would be a nightmare to try and cut it all in one piece, I'd think you'd want to cut the center spindle and the helix pieces separately?
The modeling part would go like this:
Draw in a polyline profile curve like this:
Select it and run Construct > Revolve. In the prompt in the upper right corner of the main window, MoI will be
asking for the revolve axis which you'd want to pick along the z axis direction like this:
That will make the main central piece:
For the helix pieces go to Draw curve > More > Helix:
Pick the points for the helix axis along the z axis as well to make a helix curve like this:
Then draw a circle off to the side, select the circle and use Construct > Sweep and pick the helix as the rail path to make a tube
around the helix curve:
Then you'll use Transform > Array > Circular to duplicate the tube.
You'd probably want to extend the helix a little more into the top and bottom than what I've done here.
But constructing the 3D model is going to be by far the easiest part of the whole project I'd think, and MoI would work well for the modeling part.
The fabrication probably wouldn't be so hard if the helix was a negative shape cut into something. But a free-standing helix? Seems very difficult.
- Michael
