[mike stables]

Does anyone know how to fool the system so you can machine an undercut in Rhinocam in 3d? You can do it OK in 2.5d with a lollipop tool but in 3d? You can lie to the system about the tool size but getting it to where you want it without fouling the job is a bit of a problem. Any ideas gratefully received.
Mike

[pointcloud]

Use the 4 axis and rotate. You will have to create boundries and watch your Z because Z0 will become the center of your fourth axis.

Another option if you do not have 4 axis machine!

create your code with the work at an angle, when you set up run one level and then reset to the angle you used with creating the code.

Check and recheck Z, when you rotate the part Check and reCHECK all locations relative to X0 Y0 Z0....

[mike stables]

thanks for the reply - I do have 4 axis but that only works on some shapes. I'm machining a shoe sole mould which has a lip running around the sole overlapping the wall of the sole by about 2mm, and not only can't you do toe and heel in 4 axis (unless you turn the job) but even with 4 axis you can't get sufficient angle to undercut that without fouling the machine spindle. A spherical burr or custom made tool would do the cutting OK - if I could just find a way to program it.

[pointcloud]

Ok... I guess you'll have to do the best you can.

I have made some fixtures for these type problems, that makes it where I can set up easy and fast for the next machining process...

Then you might have to lie about it haveing 5 axis and use a fixture to get the max angle....