[Beezer]

I am trying to draw a 3D model of a part that I need to get CNC'd but I am stuck at a point and really could use some help from you AutoCAD guru's.

The part in question is a cylinder that has a slot cut into the outer surface around the entire circumference of the cylinder. Now the slot has two sections where it follows in a straight radial direction. One is located at the front and at the top of the cylinder. The second is loctated at the bottom and towards the back of the cylinder. The end of each of the straight slots is connected to each other by a diagonal slot that follows the contour of the cyclinder. Basically this part is a cam. Another part, which has has a pin in it, will follow the slot in the cylinder.

I have been able to draw the cylinder and the two straight slots but haven't been able to figure out how to do the diagonal slots.

I have attached the cad file of what I have gotten so far along with a picture showing what the part should look like.

I just don't want someone to finish the drawing for me but I would like to learn how it is done as well for the future.

Thanks

[ger21]

Extrude a solid along a helix, and subtract it.

[Beezer]

I am a newb when it comes to working with Autocad in 3D. Could you explain abit how to do this? What info will I need to know about the helix to get it to turn out properly?

Thanks

[C.Michael]

The way I would do it is with the 3d slice command..Imagine a round loaf of bread that you cut at an angle twice and then remove the slice of bread that you just cut..You have to draw a 2 d drawing first to show the angle of the cut..Then when you have the slice out of there,hollow out the bread with another circle extruded thru the middle of it..Follow the idea?

[Beezer]

I will give the slice command a try but I have a feeling the edge of the slot will not be correct. The edge or wall of the slot needs to stay at a 90 deg. angle in relation to outer surface as the part is rotated in the 4th axis.

I have been playing around with extruding of a helix. Still not getting the correct twist of helix to match the cylinder diameter. Will keep plugging away at it but I have a feeling that AutoCad can't do exactly what I want easily. I may need to have someone with Solidworks give it a try.

[Kiwi]

I may need to have someone with Solidworks give it a try.

This may help. Drawn with Solidworks.
Small bridge across slot to join two halve which you may need to remove.
See attached IGS file.

[Kiwi]

Beezer...Altered drawing and attached updated IGS file.

[Beezer]

Kiwi...That looks great. Thanks.

Looks like I need to give learning Solidworks another go. Seems it could come in very handy.

[HuFlungDung]

While modelling the groove is an entertaining exercise, it probably is a waste of your time when it comes to actually machining the feature (just like modelling threads is a wasted effort for lathe cut threads). Helical grooves are typically cut with 4th axis wrap, and you only need the 2d map of the surface unwrapped and laying on the XY plane.

[Beezer]

True... but I want to take all the 2D plans for the project I am working on and turn them in to 3D models. This cam part with the groove had me stumped.