i guess a good rule of thumb is you want to make chips, like foil bits, not powder or little chunks
not a grinder, not a shaper
'grinder' machining is like, super high speeds, low feeds, so while it might sound okay and produce great finishes, makes a lot of heat and take a lot of cuts, eats tooling up fast
like if your coolant turns to fine metallic paint, spin slower, feed faster, and if it sounds rough, dont go as deep
Posted by renesis at 13:46 | permalink | 0 comments
spindle speed and feed rate you should keep within typical windows, too far outside and youre probably wearing through tools too fast even if it 'feels' right
depth of cut is totally a 'feel' thing, completely depends on the machine and the job
like, big machine wont do order of magnitude more speeds and feed than my mini mill
but they can do orders of magnitude deeper cuts, using more of the cutting surface
anyway the math is simple, so calculators are fine
Posted by renesis at 13:39 | permalink | 0 comments
0.001" is a typical finish chip load, 0.005" would be pretty big, both pretty reasonable
divide those in half for little machine
then your depth of cut depends on the spindle power, machine rigidity, and how tight the part is held down
tool life is related to heat and the number of cuts taken
so you generally want to feed as fast as possible with as large and deep a cut that the machine can handle
coolant helps keep heat down
Posted by renesis at 13:33 | permalink | 0 comments
jero32: re: speeds and feeds...
you look up a surface speed for your combination of metal and tooling (HSS vs carbide mostly), then your tool diameter determines the RPM
basically so that the speed around the circumference at the max radius matches the target surface speed
then you use the number of flutes and desires chip load per cut to find the feed rate
desired chip load is a product of desired finish, machine rigidity and spindle power
Posted by renesis at 13:28 | permalink | 0 comments
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