Pro tip: Always check your coolant concentration before a big production run

I was running a Haas VF-2 last Thursday in Toledo. Parts started coming out with this weird rough finish. Looked like sandpaper. Spent an hour messing with feeds and offsets. Nothing worked. Shop foreman walks over, dips a refractometer in the tank. Coolant was at 2% instead of 8%. Mixed a fresh batch and the parts came out perfect. Felt like an idiot. Has anyone else had surface finish issues traced back to coolant ratio?

3 comments

3 Comments

alice26929d ago

Grabbed a refractometer right after reading this, checked my own tank and it was reading 3%. Mixed it back up to 8% and the finish on my aluminum parts went from rough to mirror smooth in one pass. Also found out the hard way that running too lean makes the coolant go rancid faster, had to dump a whole tank last month because it smelled like a dead animal.

the_brian29d ago

Whoa, you're probably the first person I've seen mention how coolant concentration actually affects rancidity like that. I wonder if the bacteria that make the coolant go bad have a harder time surviving in higher concentration, or if it's something else entirely going on there. That's a really good side effect nobody talks about.

jana_scott26d ago

Grabbed my refractometer and realized it was just sitting in my toolbox collecting dust for six months. Checked my tank and it was at 1.5%. Felt like a genius when I mixed it back to 8% and my parts stopped looking like somebody sandblasted them with gravel. Now I check it every Monday morning like a weird ritual. Still can't believe I ran a whole shift on basically water without noticing.

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