On 8 Dec 2003 18:18:56 -0800, the renowned
(Marshall Johnson) wrote:

jim rozen wrote in message ...

Post up the sfpm you were running on the tool,
and the feed rate. Either your idea of 'slow'
for the rpm is incorrect, or you were running
the feed rate so slow as to allow the material
to work harden under the tool.


Sorry for the late reply.

The spindle speed was 200 rpm. Originally the feed rate was 1.5" per
minute, but that was when we wrote the program for the mild steel. By
the time we were taking a good cut into the metal, we had the feed
rate slowed down to about 1/10" an inch per minute.

The feed rate, if it was right originally, should not be that much
different. The spindle RPM ought to be much less. But, as Jim said,
what's the cutter diameter of your 4-flute end mill?

RPM ~= SFM * 4/(cutter diameter)
Feedrate = RPM * feed per tooth * 4 for a 4-flute end-mill

(the recommended feed per tooth also depends on the cutter diameter)

Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
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