Originally Posted by keithmcelhinney  I have been working with my nm135 for a couple of months now and got some good parts done. Now I am looking at doing some parts to sell and naturally want to be able to cut my time down as much as possible. I am doing mostly contours and some pocketing. I have used the 2 flute (long) and a 3 flute (short) 3/8" carbide end mills. I run at 3200rpm with the 2 flute at about 7ipms and the 3 flute at about 9ipm. My cut depth is .05. Now it runs pretty good but it takes a LONG time. I tried a 5/8 carbide end mill for clearing the pockets and proceeded to break it almost immediately. It was when I first started and I had my plunge too high I think. But it seemed like the spindle couldn't handle plunge cutting with such a big end mill. Naturally I don't want to spend $60 and try it again without making sure it is going to work. Does anyone have any suggestions how I can speed it up? Should I go a little deeper? I can't see going any more than .06 but don't want to break end mills or screw up the machine.
Also I was looking at roughing end mills. Would this be worth looking at when I am not going very deep? Would I be able to cut deeper?
What are you guys running when you are trying to remove a lot of material? I have 2 parts that I am removing 4-5 square inches and an inch deep. I do not need to have a good finish on it since I do a finish pass on everything. Any suggestions as to end mill size,depths,speeds would be awesome.
Thanks!
-Keith |
you dont mention waht you are cutting. if its aluminium, put the rpm to 6000 (if your machine version handles that), and take shallow axial cuts at a much much higher feed rate. for example, you should have no problems cutting .375" deep, .125" width, at 35 to 50 ipm with a 3 flute .375" uncoated carbide. you probably should use at least a mist coolant (spray bottle) to help keep the chips from sticking to the tools, as well at climb cutting when possible. avoid doing cuts more than 75% of the cutter width.
on plunging... dont. any vibration from plunging seems to damage caribe end mills and most of these small bench mills have plenty of give in the head to cause this. its best to ramp or helix into a cut (on any machine really) at about 30-50% of your normal feed rate. you can also get a tool with a small radius on the tops, which will reduce chatter and the likelyhood of breaking the bit. if helixing isnt an option due to cam abilities, you could drill a pilot with a larger bit than your end mill and start from there.