Machining Lot Of Fillets

[BillGEGHV]

Hi all, 

I’m getting pretty close to finishing a model of an AR-15 lower receiver (Air Soft Gun Part), not a real steel part. Going to start adding all my fillets in CAD and I wanted to get input on machining them.  Since there are so many fillets, is it best to machine them using corner rounding end mills OR is it best to surface machine them all with ball end mills and parallel finishing type tool path?    

[a.laasW8M6T]

Hi

The correct answer is, Depends......

a corner rounding cutter is way faster and leaves a great finish, but depending on the geometry you may not be able to cut all the fillets with such a cutter.

If the fillets are not simple and have more 3d geometry(like are not all along the same z plane) then you will have to 3d machine them with a ball/bullnose)

I wouldn't use parallel to machine fillets.

Blend/Flow/Geodesic are the best for machining fillets

You can use scallop too but I don't like the finish left by scallop toolpaths

[BillGEGHV]

As always, thank you sir. I did not think of a bullnose as an option, I think that could be good for some flats that have bottom fillets, which in my case, they all do. Maybe I can look at doing some of them with corner rounding for the sake of speed, where they are simple top fillets and then bull nose at the bottom?  I will look a the tool path types you suggested, much appreciated.