Standard end mill flutes produce a continuous, unbroken chip. Most of the time that's fine — the chip clears the flute and evacuates on its own. But in deep pockets, long-reach setups, or aggressive roughing passes, a long continuous chip can outgrow the flute's ability to carry it out, tangle around the tool, or re-cut itself on the way past. Chipbreaker geometry exists specifically to solve that problem.