How would I machine this complex bust on a 4th axis?

[Anonymous]

My teacher wants me to machine busts of our Freshman this year, changing it from the normal 3D printing we've been doing. This is my first try at machining and I have little to no clue on what to do.

I've looked up videos showing how to do wrap machining with 2D Adaptive clearing but those only work for pockets it seems, and with a complex model like a human bust with so many contours I don't think I'd be able to select them all. Also correct me if Im wrong but isn't wrap machining also only for 4th axis machines with a 4th axis drill?  Our machines 4th axis is on the collet rather than the drill.

If someone could help me out with this thatd be appreciated. I can give any details necessary to assist. Below are images of the bust and it's stock.

[seth.madore · Accepted solution]

Wrap machining is for a 4th axis mounted along the X or Y axis of a machine, like this:

The above photo is something I pulled off the 'net, but it represents the idea.

Wrapped Machining really only works for round parts and features that run along the axis of rotation. For instance, a tapered screw or spiral would NOT be able to be machined with Wrap Machining.

So, full on machining of busts is going to be a tough one currently. You can try 3+1 where you index to a set angle and perform a bunch of work with the 4th axis locked, but that will only get you so far.

There is a new Rotary toolpath that "might" get you far enough, but it's behind a "Feature Flag" and essentially still in development. Learn more HERE

[johnswetz1982 · Accepted solution]

When working with STl files you will want to be using 3D toolpaths. For your case use 3D adaptive to machine down to the roughly the center axis (the less deep you can get away with the better). Duplicate the toolpath and change the [Tool orientation] to be 90 or 45 or however many degrees you want. Repeat.This will rough the stock out around your part.

Optional step, Repeat above with ballmill to remove sharp steps from roughing.

Then pick a 3D finishing toolpath, [Morphed Spiral] for organic shapes. Repeat the tool orientation to index your part around and finish at the orientations you roughed at. OR/And you can use the experimental [Rotary] toolpath as your finishing tool OR use it after the [Morphed Spiral]. See example photos of indexing for roughing then finishing. 

Rough

Tool orient, repeat

Ballmill semi finish

Rotary

Also check out Titans of CNC Lion head. That will show you same process.