Our shop got a new batch of coolant concentrate and I mixed it too strong, like a 1:8 ratio instead of 1:12. Ran it for about 8 hours before the machine started throwing alarms and the finish on the aluminum parts looked terrible. Had to drain the whole tank, clean the lines, and remix. That cost us nearly $500 in lost time and wasted material. Always double check the mix ratio on the drum, even if you think you know it. Has anyone else had a coolant concentration mess up a job this bad?
Wait, you run stronger for aluminum? That's the opposite of what I've always done. Too rich a mix can really mess with the finish because it doesn't wash away chips right and leaves that sticky film. It also gums up the machine way faster. I've seen it cause exactly the kind of alarm issues he's talking about. A leaner mix usually works better for me to keep things clean and cool.