Hi,
My own built mill is all cast iron and steel, and not in anyway treated or painted. I use water soluble oil and water at around 35:1. I don't really get any corrosion,
a little surface rust but that's about it. I've had this machine in service for 3.5years with little or no rust.
I use a 1/8th hp single phase pump with a 12l tank. Had it for nine years, and it does OK, but I want better. I recently upgraded my spindle (3.5kW(S1), 3.4Nm(S1), 10krpm (rated), 40krpm (max), HSK32E tool interface)
and am now making a lot more chips. Want a much larger volume tank, about 200l, with 600 x600 gauze filter and a three phase pump producing something like 80l/min.
I really want to wash the chips 'down the drain', and you just need a lot of volume. I also have two stainless magnetically coupled (no pesky shaft seal) gear pumps that do about 5l/min but will easily get to 100psi.
I want a portion of the main coolant flow to divert through a fine gauze and/or paper filter and feed these pumps with that extra filtered coolant. They will 'squirt' out really nice and flush the chips away from
the cutzone........and that is the whole secret to milling aluminum in my opinion.
That's what I do.(C) Should I just dive in and use flood coolant for both cutting and washdown?
I'm hoping that when I get my new tank and pump running that washdown will be quicker and more effective.
In my opinion the trick to using flood coolant well is to have really good coolant containment around the milling area, a readily accessible, readily serviceable large area filter to get rid
of chips and a large tank.
Cleaning up coolant leaks gets very old very quickly. Wrecking a part because the coolant got blocked somehow, somewhere and you did not notice it until the part and tool are wrecked
also gets very old.
Things like nozzles that constrict the flow are exactly the sort of places where chips/dross entrained in the coolant flow block up. Gauze or other filters that get too loaded with chips too regularly
are another source of leaks or overflows. Anything that minimizes leaks, blockages and overflows is highly worthwhile. University students are notoriously ham-fisted, and teaching or rather demonstrating
proper industrial coolant handling will stick with them forever.
Craig