PSA: Ran into a coolant concentration problem at a shop in Houston last Tuesday

I was visiting a buddy's shop down in Houston helping them set up a new Haas VF-2 and noticed all their parts had this weird staining. Turns out nobody had checked the coolant mix in like 6 months and it was way too rich, something like 15% instead of 8%. They had been swapping tools every 30 parts thinking the inserts were bad when it was really the coolant causing chatter. I brought a refractometer with me and we dialed it in to 8% on the spot. First batch of parts after that ran 80 pieces with no issues. Has anyone else chased production problems that turned out to be a simple fluid mix issue?

2 comments

2 Comments

terry9142d ago

Had a buddy out in Dallas last spring. Same damn thing. He was pulling his hair out over a Mazak lathe that kept giving him shitty surface finishes. Changed inserts, changed feeds, even called the tool rep out twice. Finally I stopped by and saw his coolant looked like chocolate milk. Thick as syrup. Grabbed his refractometer and it was reading 18%. Drained the whole sump, mixed fresh at 7%, and the lathe ran smooth as butter the rest of the week. He was ready to scrap the machine. All over coolant.

riverowens2d ago

Devil's advocate here but sometimes that 18% mix was KEEPING that machine alive. I've seen shops run thick coolant on purpose when they have hard water or old machines with worn ways. The extra concentration can help lubricate things that are already loose. Not saying it's right but maybe that Mazak was compensating for something else like a worn turret or bad bearings. Also your buddy changed inserts and feeds BEFORE checking coolant? That's on him not the coolant. Experienced guys check the basics first like concentration and pressure. Sometimes the machine is just lying in wait and the coolant was the scapegoat.