[zappafan1]

I have been using a HSS .375 (3/8') 2 flute, non-center-cutting flat nose end mill to cut shapes out of a .125 6061 T6 Aluminum. My feeds and speeds have been varied between 2000-4000rpm and 10-18 ipm, during which I have been getting this fountain/melting effect with the edges of the cut. (I have attached a picture of a cut I just finished).

Is there any advice to why this is happening and what I can do to avoid this?

Here's the Feed and Speed info I received from 2L Tool Company. For me, these seem to be working quite well for the 6061 and 6063 Aluminum I'm working with; both milling/slotting and spiral drilling. I'm using a one-flute .250 end mill, and I use windshield washer fluid with 1/2 cup Dawn dish soap per gallon.