A little advice please. I need to cut a few parts out of 3/16 aluminum plate (type of aluminum unknown). I would prefer to use 1/4 two flute upcut bits as I have many to play with. Can someone give me some starter advice on speeds and feeds with my R7? No clue where to start and am not that interested in getting into cutting much aluminum, I just need to know where to get going. I plan to just profile a couple of 10 x 10 and 10 x 20 plates. Thank You in advance!
With aluminum it will depend greatly on the type of machining paths you are creating. You will want to be careful about chip clearance and how much force you’re putting on the bit, even with 1/4" bits.
I have had good success with 24k RPM spindle speed, 2000mm/min, 1mm DOC for roughing cut. I usually leave 0.635mm on the walls and 0.2mm on the bottom to then be cleaned up with a finish pass at the same settings. This will probably seem like madness to some but it works for me.
If you look back through the group you can see my earlier trials with Aluminum cutting. In the end the thing that made the biggest difference for me was switching to High Speed Machining toolpath styles and making the head move faster but with light passes.
I’d advise you get some scrap to play with, it is definitely a learning experience but is a lot of fun!
Thanks Ben. I have been keeping up with your adventures in aluminum but could not find where anyone specifically gave advice for the 1/4 bits. I appreciate the help!
Ben when you say .635 mm on the walls are you referring to the entire thickness being finished in the last cut? How much step over would you recommend?
On the finish cut I stepover 0.635mm and down 0.2mm. So it’s a very light cut but will be at the full depth of your part. This was with a 2 flute upcut 1/4" bit with coating.
Understood! Thanks
Big bit Mr. @Matt_Clinton you can cut back on Ben’s settings, even more than mine at 6.35mm turning radius. Big moment arm out there. On top of that you are in super thin material.
It can be done no doubt but may benefit you a load to go smaller. Like 1/8"