On Thursday 20 August 2020 16:01:15 John Dammeyer wrote: > Does anyone use mist coolant? If so what sort of fluid? Mixed with > water? If water then how do you dry up things so rust doesn't happen. > > I mostly mill aluminium castings but occasionally steel. > > Thanks > John Dammeyer > I do John, particularly with alu, and the stuff I bought is mixed with water at about 1/2 oz of it to an 8oz plastic coke bottle as a peer machine reservoir. I drive it with both shop air, and a peristoltic pump similar to whats on the tree beside your hospitals marquee de sade appliance called a bed. So I generally have a pretty dry, just enough mist to cool a carbide tool and keep it from gumming up in softer alu, welding the gullets full and breaking the $20 tool. Where I'm using it is on my 6040 gantry which has a 1.5 horse 24k motor with an 1/8" collet style chuck. All controlled by LinuxCNC's Axis mist button. of coarse. That evaporates, so wet isn't huge problem. I have in my hal file, a couple oneshots that feed each other, with a pair of pyvcp sliders so I can control both the on time and the off time of power to the pump. So the pump gets bumped 60 to 400 or so times a minute for a small fraction of a turn, and an adjustable off time. Properly tuned, that 8 oz coke bottle will run it several hours.
The stuff I bought to feed it is called Kool Mist, comes in gallons at a bit over $30 IIRC. So far I've used about 3 oz to make the mix in the coke bottle that feeds the pump. I bought 4 of those pumps for a tenner each because I've got 4 machines, but the delivery nozzles at $6 to $15 a copy are all junk, intended to deliver flooding liquid and I haven't tripped over a good mist nozzle yet, or I'd have it installed on the other 3 machines too. As is I spent a week modifying one of the $15 nozzles for best effect. Keeping the work damp with shop air driving the mist, the coat of mist slows the formation of alu oxide behind the cutting edge of the tool and that slows the part heating to a greater degree than the evaporative effects. Slowing the oxidation formation also means there is less of it for the tools approaching next cutting edge to cut through and extends the life of the tool many times. I can't afford the tool breakage of a clogged up tool, and this stops 99% of that. Direct the mist so it hits the work right behind the cutting edge, getting it wet as quick as the cutter has spun past for best effect. Those pumps came from fleabay, search for "peristaltic pump". They work by spinning a roller over a loop of si tubing, which will eventually crack and fail, but these pumps aren't foxy enough to spend the time putting new tubing in when it does. Its an expendable service part. Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
