1/8″ 2 flute end mill, .3mm DOC, 5 mm/s, 2mm/s plunge. No coolant with the dealt at about 90% max speed.
My tool was way up but I could easily go another 1 1/4″ higher. and cut faster or deeper.
A few things here. 4″ z and you can only get a 1″ block under the aluminum? Is your endmill all the way in the dewalt? How long is your bit? You speed is more than 2x’s mine I would slow down. The standard feeds and speeds do not really apply to us. We should not be using 2 flute bits We can not travel fast enough to keep the chip load high enough or slow the spindle down enough and retain torque. I used it because It was all I had at the time.
Before you modify things take a few more tries. It took me 3 tries to get it right but once I did the aluminum cuts just fine. Wood and plastic is very forgiving aluminum is at the edge of the machines capabilities, but it does work and when you set things right it works great.