I'm cutting through an aluminum block 1.5" deep with a 3/8" cutter.
I'm using flood cooling. The chips pack up underneath the through cut and then the chips start coming out of the top. The coolant still flows out the bottom.
I'm wondering if I would be better off with a sacrificial plate underneath, turning it into a deep pocket. That way the cutter is completely submerged, and the chips always flow up and out, rather than the flow pushing the chips down and the cutter pulling them up. I figure the coolant will be helping the flow then.
Jack the plate higher and use another coolant line under the plate. Double cutting the chips just wears the cutter out faster. Just a thought without seeing the part. I always use tall rails to help get the chips out on a through cut.