Re: Machining Aluminum Dry

On 11/5/2024 4:56 PM, Joe Gwinn wrote:

On Tue, 5 Nov 2024 16:40:54 -0700, Bob La Londe <none@none.com99>
wrote:
 

First off let me emphasize I firmly believe based on hearsay, direct
knowledge, experience, and the opinions of experts that a flood of water
soluble cutting coolant like (but not limited to) SC520 and water is the
magic sauce.
>
In my journey to that conclusion I tried a variety of other options from
standing there for hours with a spray can of WD40, to crappy little home
made mist systems, to brushed on cutting oil, to air blast, to vortex
tubes, and even ran flood *transmission fluid for a while.  Flood
transmission fluid was the best until I went to flood water soluble
coolant.
>
As I bragged shamelessly about in another post I finally got around to
buying another CNC wood ripper.  Wood Ripper 2.  Wood Ripper 1 has been
disassembled and the parts stacked out of the way for some time.  Like
with Wood Ripper 1, Wood Ripper 2 was not intended to be used with
metals.  Atleast not initially, but now some of the projects seeping
into my front brain involve sheet aluminum.  I suspect some aluminum
cutting will be coming along sooner than originally planned.
>
Now before anybody says, "Well I cut aluminum dry or with just a little
cutting oil brushed on all the time," I know.  I actually do too.  On
the manual knee mill I cut blanks square and to length all the time
before taking them over to one of the CNC mills.  A very light spray of
WD40 is what I usually go with.  Tap Magic is a little better, but a
spray can of WD40 is so much easier.  A quick sprits and wave and start
turning the handle almost as fast as I can.  Typically I make a rough
pass in climb to remove the bulk and a spring pass in conventional to
clean it up.  I know that may sound backwards to some, but it works.  I
do this with a 1/2 inch 3 Flute Alumacut mill from *Rogue Systems Inc,
and the one in the tool tray by that machine is several years old.  With
smaller mills I have run into problems, but that big old polished 1/2
inch mill is amazing.  Chips just fly, and big ones.  Once it gets a
little warm on the spring pass it can throw chips back on the finished
surface and they will stick if it doesn't get a sprits of WD first.
>
Well on the new Onefinitey Elite I'd need an enclosure 64 x 68 inches
roughly square (bigger really) and the mother of catch basins to run
flood coolant.
>
When I was still fighting flood every way I could I tried some of the
coatings that are supposed to be the juice for aluminum, and honestly...
well they aren't.  ZrN, PVD Diamond, etc.
>
So now with this new machine coming into the shop I am regressing.  I'm
looking for a less than full flood answer to cutting aluminum without
chip welding, breaking cutters, and ruining work pieces.  So far my best
compromise might be spray mist with a vacuum recovery system.  Hopefully
the liquid from the mist would drop out in the separator like chips do.
>
For now my conclusion is still that based on hearsay, direct knowledge,
experience, and the opinions of experts that a flood of water soluble
cutting coolant like (but not limited to) SC520 and water is the magic
sauce.
>
*  Yes flood transmission fluid worked, the parts looked great, cutter
life was very good, and my shop smelled like a turbo hydro 350 burning
up because somebody put the wrong clutch piston in it during a rebuild.
It would consume the fluid.  Either burning it or vaporizing it, but it
produced great results.
>
**  Rogue Systems Inc is a small (one man maybe) CNC grinding shop in
the PNW (No Snag, I don't think he's a slug) that produces a range of
solid carbide ball nose and square end mills sold on eBay and on his own
website.  Carbide Tool Source.  His Alumacut end mills are every bit as
good as any other aluminum geometry mill I have tried and a little
cheaper than most.  He also makes the least expensive solid carbide
multi flute single form thread mills I have run across.  Well and a few
other things.  Solid carbide boring bars, multi form thread mills, and
some other cool stuff.
>

 I'd try alcohol in water, but dilute enough that it cannot catch fire.
 Joe

Yeah, IPA cools from evaporation.  You do have to have direct ventilation or you wind up with a toxic work environment.
--
Bob La Londe
CNC Molds N Stuff
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