Tried a new coolant mix on our Haas VF-2 and the finish went all wrong

I swapped from our usual 8% mix to a 5% blend with that new TrimSol E210 stuff, thinking it would save a bit of cash. Ran a batch of 6061 parts and they came out with this weird, almost etched-looking surface that felt rough to the touch. Learned the hard way that even a 3% change can mess with chip evacuation and tool life big time. Anyone else run into finish issues after tweaking their coolant concentration?

2 comments

2 Comments

drewp758h ago

That's a solid point from @wendy_clark about the chemical stain. I always blamed poor finishes just on the tool or feeds, but a bad coolant mix can totally leave residue. Had a similar thing happen with a weak mix on some steel, left a sticky film that ruined the part. Makes you check the refractometer twice now, doesn't it?

wendy_clark12h ago

Honestly, have you checked your shop's humidity lately? A weaker mix can let water evaporate faster off the part, leaving the actual chemicals behind to dry on the surface. That etching sounds like a chemical stain, not just a chip issue.