novakon + kittens + brass =

[ihavenofish]

brass kittens!

made these yesterday on the nm145. turned oor ok, bu tthe only bit i had was an overly long high speed steel 1.4" and it chattered and chipped the teeth resulting in a poor finish on the sides. going to do some more soon with a better stup. ive done brass before with carbide and the finish was perfect, so i expect i can get the same results on these kitties.

doing an aluminium non kitten related part today, going to see if i can get a nice video of it cutting.

[SpeedsCustom]

What are your speeds , feeds and DOC /SPINDLE?


-Jason

[Novakon Support]

Hi Jason,

We can recommend a spindle speed of 5000 rpm, a feedrate of 20.0" per minute and a Depth cut of .020" for the alluminum. Should you get tool chatter when cutting the brass, reduce your feedrate to 15.0" per minute. These are recommendations for a four flute 1/4 inch cutter.
We also recommend climb cutting for all cnc operations.
If you are using a longer than normal cutter, you will also have tool chatter, so try to minimize your tool length.

Regards,

Ronald Moodley (Novakon Support Team)

[ihavenofish]

Hi Jason,

We can recommend a spindle speed of 5000 rpm, a feedrate of 20.0" per minute and a Depth cut of .020" for the alluminum. Should you get tool chatter when cutting the brass, reduce your feedrate to 15.0" per minute. These are recommendations for a four flute 1/4 inch cutter.
We also recommend climb cutting for all cnc operations.
If you are using a longer than normal cutter, you will also have tool chatter, so try to minimize your tool length.

Regards,

Ronald Moodley (Novakon Support Team)

depends entirely on the tool and the operation.

i was using a long 4 flute cobalt bit in the brass. rpm with flood coolant should be more like 2500-3000rpm, feed was 10ipm for slotting, which was not ideal. finish pass was 5ipm, but by then the cutter was dulled and didnt do very well at all in terms of finish quality.

with a short 3 flute high helix carbide cutter 6000rpm is good, 20ipm in slotting with a 1/8-3/16" depth. 15-30ipm for the full 3/4" finnish pass depending on the rigidity of the work piece, machine and tool. thats basically the settings i used on the guitar bridges i did a while back. with a rigid setup and carbide, you can blast through brass like butter.

for the aluminium part i used a 2 flute carbide bit, a little too long a flute length. 1/8" width, 1/8" depth, 6000rpm at 10ipm with coolant. a little chatter in the roughing, but generally good results. should be doing some more of this part today or tomorrow with a shorter 3 flute bit which will improve finish and throughput alot.

should be noted that with the current spindle driver issue in the nm145, the spindle is going slower than programmed in heavier cuts which leads to a heavier feed per tooth and thus more flex and chatter. this needs to be compensated for with a little on the fly testing.

i also noticed today my z axis gibs are slightly looser than they should be, which may have been contributing to chatter a little. ill be snugging those up for the next run.

[SpeedsCustom]

I'd like that, I like high helix cutters, especially 3 flutes and I mainly cut aluminum. I'd be very impressed with a 15-30 IPM at .125 DOC. My part would be clamped and solid, so chatter shouldn't be an issue. I'd also be using the coolant. I don't ever use long flutes for my application so I should have a pretty rigid set-up.

I'd like to get the 145, but I have to see how everything pans out.

-Jason