PSA: I just found out how much coolant flow really matters for tool life

I was reading an old shop manual from the 90s my boss gave me, and it said something that made me stop. It claimed that for a lot of aluminum jobs, increasing coolant flow by just 20% could double the life of an end mill. I thought that sounded crazy, so I tried it on a simple pocketing job we run all the time. I bumped up the flow on our machine and ran the same program. The tool looked way better after the run, with way less built-up edge. I checked the inserts after and they were definitely in better shape. It seems so simple, but I guess I never really paid attention to the flow rate beyond just making sure it was on. Has anyone else done a test like this and seen a real difference?

3 comments

3 Comments

victor_carr251mo ago

I mean I used to think coolant was just about keeping things wet but that bit about checking the pressure gauge really changed my mind. I always just turned the knob and assumed it was good enough, never thought about whether the flow was actually reaching the cut. Now I'm definitely gonna start paying more attention to both flow and pressure, seems like an easy way to save on tools.

adam6753mo ago

Coolant pressure matters just as much as flow. High flow with low pressure won't clear chips from deep pockets. The stream needs to hit the cut. Seen tools fail because the coolant just washed over the top of the work. It's not just about turning the pump up. You need to check the nozzle position and pressure gauge. A lot of older machines have weak pumps that can't push enough.

the_karen3mo ago

Yeah, pressure is huge for deep cavity work. I was reading a machinist forum last week where a guy kept breaking long reach tools in aluminum. He had tons of coolant flow but the pressure was too low, so the chips just packed in there and welded. He added a secondary high-pressure line just for that job and it ran perfect. Makes you check your own gauge.