Just broke my brand new 1/8” O Jenny O Flute bit I received from Cadence in the mail today. I ordered it Tuesday on the same 1/2” piece. I’m trying to create a router slab flattening mount out of 1/2” 6061. The first bit was complete stupid human error. I mis-typed my spindle speed in as 1800 RPM. I’m not confident I know what just happened but checking for understanding.
The large pocket and two holes were cut with 1/4” O Jenny. The last time I cut aluminum (last week), I flooded my piece with WD 40. The result was I clogged my dust handler and ended up cleaning that up after the fact but I did have a successful cut. So, this week after I broke the 1/8” trying to cut 6 MM through holes for my carriage mount, I decided to push on with the pocket on my 1/4”. This time I hooked up 20 psi air and it worked great. No mess and no problems. Tonight I noticed my air nozzle was not fitting all the way under my brush on my shoe. It cut 3 holes all the way through just fine, but when it moved to cut the fourth I heard the snap through my ear muffs.
Looking at the damage, I think I welded a chip to the midpoint of the cutter in the 3rd hole. The cutter was cold to the touch and no problem handling it. However if you zoom the photo it appears there is a chip.
if I’m correct-when I get my 3rd cutter next week-I need to raise the shoe up higher and make sure my 20 psi air is forced under. Can someone speculate on my theory?
pass depth 0.015, step over .025, spindle speed 18000, feed rate 25 ipm, plunge rate 15 in/min. And not that I matters, had the same x,y zero for days and used glue and tape for my hold down. It isn’t moving.
I have a 1f gen1 elite foremen with a masso controller. Been a machinist for 45+ yrs and I do have a manual bench mill in my shop to machine metals.
I have not tried to mill Alum. on the 1f yet but I would add a ramp tool path option in a spiral pattern. Also go to a convention on direction. Maybe go up to a 1/4 2 flute end mill, the 1/8 0’flute end mill might not have enough strength to cut alum. So if you are plunging straight down this is were the end mill is getting weld back of the material to the cutter. By spiraling down in your plunge might solve the weld back, otherwise I think your feeds and speeds are ok but maybe slow it down a bit until you see a nice clean short thin curly chip. I know what I am looking for in a chip but I am having a hard time trying to describe what it actually looks like. You can also adjust the feed rate down or up with the override option and listen to the sound of the machine. It should sound smooth with no chatter sound or vibration in the rails or gantry. In the industrial machines I run, I always tell the new machinist the sound is kinda like a sha-shing sound, here again my description is kinda my own explanation. It kinda turned into a joke with some of them and I became to be know as the old sha-shing sound guy.
If you can’t get a smooth sound than go to the spindle override option and go up and down with it. Once you find the sweet spot you will know it is right. Just take the percentage rate and multiply it by current feed or speed it was programed at.
examples - program feed 15 x percent(%80) 0.80 = 12 do the same with speed.
doing any type of aluminum requires some type of lubrication (you don’t need to flood it )
but an occasional squirt of something - WD-40 is fine otherwise its going to get the material too hot and it will melt it around your tool.
As suggested use the ramping feature to get to your depths you desire and don’t use the vacuum system -have a shop vac that you can use on the side to clean your project off when it gets a little messy.
one more thing - try not to leave the chips that you just cut in the path of your tool as it goes around to make another cut. - its just hard on your tool bit having to cut the new material and the chips that were left from the last cut.
