Hot plunge milling - GIF

[Toolmaker51]

Heck; why no description of material, cutter choice, RPM, FPM.....? Carbide cutter, probably AITiN (Aluminum Titanium Nitride), guessing 1/2" ~ 5/8" diameter, 4 flute, ~1/8" corner radius The real issue in plunge cutting is chip evacuation. Setup in GIF runs well enough at depth, but they're awful close to a jam ramping down at the beginning. Cutting raw solid material is one thing; chips blocking fresher chips one of leading causes in tool breakage.
My guess is insufficient high pressure narrow air stream across the cutter, into the helix out of the ramp (air from left side).
https://www.hannibalcarbide.com/tech...m-coatings.php
Yeah, a home state company. 'We' still make things here.