On 09/21/2019 05:04 PM, John Dammeyer wrote:
What sort of tool bits, RPM, feeds, depth of cut do you
use for 0.090 aluminium?
I used to do a lot of control panels and such in .125"
aluminum. My favorite cutter is a 4-flute solid carbide end
mill, I get them on eBay for about $3 each when I buy 10 at
a time. I have an old Bridgeport with the 1J head (step
pulley) so it tops out at 2720 RPM without overspeeding the
motor.
I usually do a .050" plunge step, and side cut loads of
about .020 to .030". Feeds vary. When plowing at full
width, that would be about 4 IPM, then up to 10 IPM when
opening up a slot or hole.
I generally do all the larger holes, slots, etc. with the
one end mill, and then use appropriate drills for the
smallest holes.
Part of the trick with aluminum is to keep the cutter
moving, and it is better to take a shallower cut at higher
speed and then plunge and cut again, then finally make a
finish pass taking off .010" on the edge to bring the hole
to final dimension. If you plow at full depth and keep the
feedrate low, heat builds up and then the cutter turns into
a glob of melted aluminum.
I usually do this with the panel flooded with coolant, but
for just a one-off I can brush on a bit of cutting oil, and
not have to deal with the cleanup after.
I have written a bunch of C programs that write the G-code
for typical operations like cutting holes and slots in
panels. Some of these programs are on my web page at :
http://pico-systems.com/gcode.html
My apologies, some of these are really out of date, and
ought to be updated.
Jon
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