I’ve been reading everything I can regarding machining aluminum on the Shapeoko and I’m still struggling to understand a few things. I realize questions about Aluminum are quite common, so if you’d rather I merge with another thread, just let me know.
In general, my question is what approach to take when developing cutting parameters for myself, less so on what parameters have worked for others. Right now I’m using some scrap aluminum from a project at work - very not ideal, I know - but I suspect it’s either 6061 or ATP5. I’m leaning toward ATP5 because it was quite brittle when I went to cut the supports to remove the first part.
What I’m really left wondering is where to go from here without damaging a ton of tools… Ideally I’d love to get to the point where I can make an entire part with a single end mill and not have to do tool changes, but with my current settings that doesn’t seem to be possible.
My settings for the two tools I’ve tried (approx, I was playing with feed & spindle speed to tune by ear):
- 3-flute #201
- Chip Load: ~0.025mm (20krpm, 1500mm/min feed)
- Optimal Load: 20%
- Ramp & Pluge: 400 mm/min
- DOC: 1mm
- Single Flute #278Z
- Chip Load: ~0.116mm (14krpm, 1620mm/min feed)
- Optimal Load: 20%
- Ramp & Plunge: 400 mm/min
- DOC: 2mm
- 3-flute (#201) adaptive clearing
- I think I’m not brave enough to move the cutter fast enough to generate a large enough chip to get good heat rejection
- I ruined one end mill by welding chips to it (seems typical)
- Single flute (#278Z) facing, boring, slotting
- Anything besides an adaptive lead in doesn’t seem to work well. Both higher and lower ramp in/pluge settings created a ton of chatter and sounded terrible.
- Very bad surface finish and chatter for these operations, swapping to a 3 flute and increasing RPM while using the same g-code was much more successful
- 3-flute (#201) facing, boring, and slotting
- Running slow plunge/ramp for boring seemed to work fine at 0.5mm/revolution
- Facing worked great
- Slotting was a bit sketchy, but overall surface finish was quite good (took 2 side by side passes, not just a plunge slot)
- Single flute (#278Z) adaptive clearing
- Sounds good, generates decently looking chips, work is staying cool