WTF STEEL wrote:
replying to Marshall Johnson, WTF STEEL wrote:
Marshallj25 wrote:

Hi, I'm currently making a thick flange on a CNC mill. The material
is a 1/2" thick plate of 321 stainless. Previously, we made a
prototype out of 3/8" mild steel. That piece cut relatively easy, as
was expected. We knew that the thicker stainless piece was going to
be much tougher to cut, so we made sure that we used lower speeds and
plenty of coolant.
Here's the problem: Starting with a new Sossner 4 flute high speed
steel endmill, the same kind that we used to cut the prototype, we
began cutting the 321 stainless. The first 1/8 inch or so it was slow
but steady, we expected it to be tough. But after that it began to
chatter and the cutting slowed down. By about 1 inch of cutting, the
endmill was worn out.
Something's not right here. I knew it would be tough but not THAT
tough. How come the endmill wore out so quickly? I know that people
who work with stainless don't go through 30 endmills to make a
relatively small piece.
Does anyone have any recommendations of what kind of endmill to use
to cut thick 321 stainless? Is the material that our endmill is
composed of simply too soft a metal? Replacing cutters every couple
of inches isn't an option.
I'm sure that someone can lead me in the right direction.
Thanks,
Marshall


sadly you will have to cut a few inches and replace cutter because
the 321 stainless is to tough for it to work


Bull**** . They make solid carbide end mills just for such tough materials
.. Cobalt EM's too might do the job , I haven't tried mine on that particular
alloy but it worked well on some 4140 I cut recently - I'd go with at least
3/8 or 1/2 inch , low rotation speed and fairly heavy feed with plenty of
coolant .
--
Snag



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