4-Axis floor and corner finishing

[nletwinWVXPP]

I am trying to surface machine a U shaped part using an Okuma M560 with a rotary axis. I have attached a generic example part with some of my attempts.

I have two related problems.

At the end of the U there is a concave fillet in the corner that I am trying to finish using a continuous 4-axis tool path to prevent holder/wall collision. I would like to be able to do it either with a single pass from the correct sized ball-nose tool, or using multiple step downs with a smaller tool. I have tried a 4ax multi-axis contour toolpath with collision avoidance, however the toolpath does not run up the vertical walls. I was able to get a blend toolpath to do the stepdowns that I wanted, however it is extremely slow to calculate and seems to choke when more complex geometry is present (lots of weird segments and retracts)

CornerBlend

I am also trying to use something like steep/shallow to finish the rest of the surfaces, however the toolpath does not want to go up the vertical walls. I can kind of make it do what I want by splitting the toolpath into a left and right hand version with a little bit of tilt set in the tool orientation tab, however I would prefer to not have the seem in the middle if possible 

[a.laasW8M6T]

Steep and shallow will machine all the way up the sides if you turn off contact point boundary

Its not really the optimal toolpath here

When I get a chance later ill have a look and see If I can come up with a better solution

[a.laasW8M6T · Accepted solution]

Here's a   few options to look at

[nletwinWVXPP]

Absolutely fantastic. You answered all of my questions and then some. I can't thank you enough.