dpb wrote:

What Al alloy?

Aluminum 6061-T6 Extruded Rectangle 0.1875" x 1.25"

Sounds to me more like trying to cut too fast.

I'm not sure. The chop saws for metal using 14" cutting wheels all run
at a much faster effective speed than I'm running. The smaller chop saw
I saw ran at a much higher rpm to compensate for the smaller blade.

What kind of a cut are you trying to make?

Just a straight cut.

I think one mistake I may be making is to not move the aluminum further
back so I can come down directly in the center of the piece. The blade
hits first on the outer edge of the piece then the blade comes down
through the piece into the slot below.