Any tips on what to change to improve this? First time cutting aluminum, super rough cut, lots of chatter and vibration. Feed rate was 110mm/min as Brandon suggested - RPMs were a guess using the 400W spindle - cranked it all the way up (12k supposedly) then back down a 1/4 turn on the POT to roughly 8-9k guesstimate.
@Jace_Richardson What DoC are you using? Also the speed on the spindle is crucial, you have to adjust it according to the number of flutes on your bit, feedrate and DoC.
It doesn’t look like your chip load is anything at all. You need to actually cut aluminum. If your not making chips your rubbing it away and creating heat.
What type of aluminum are you using? That can play into it too.
Hey @Jace_Richardson check your spindle rotation. Agreed with Joe, no chips.
Odd, your holes look fantastic. Is this on the same feeds and speeds as the holes were done?
Also make sure your endmill is not filled up. The aluminum will fill the flutes and give this look, or previously mentioned incorrect rotation of the endmill.
The speed is a starting point, you will certainly be able to achieve higher. Chatter is a funny this as it can come from too low or too high a speed. This relates to spindle RPM or travel, but the base speeds should give you a pretty cut on even a dull endmill.
@Alex_Lee .2mm DoC Single Flute Upcut Bit
@Joe_Spanier I don’t recall the number offhand but it was pretty soft from what I remember purchasing.
@Brandon_Satterfield Yeah it was all done on one cut. I started a second cut at 50% faster feed rate and it looked cleaner - I’m just afraid of it and don’t want to snap the bit by going too deep, too fast, too slow rotation, really just have no idea what I’m doing. Rotation is going in the right direction (checked that like 9 times). I think the depth of cut was too shallow, too fast spindle and not enough feed speed. First time use of this endmill too.
I think the next thing I cut will be a spindle holder, I think my rendition of the down and dirty spindle mount (previously posted) is adding to the vibration.
I’m going to mess with it some more and speed it up and if I break an endmill, so be it. The part I cut like this is unusable and after watching the other vids on here, I know it should be better.
Also, the video didn’t really convey the sound very well but is it supposed to be so awful? Never been around a CNC when it was cutting before so naturally I feel like I’m doing it wrong because it’s just such a horrible screeching sound (the cutting, the spindle and motors are super quiet).
^-- screeching = vibration noise you kinda here between 10-13 seconds in
Screeching is a very high vibration, most likely down low (bit to the metal) but could be from elsewhere.
Whatever you did for the holes follow through with the profile, they are clean as can be.
The endmill was new, :-).
I know this is an old post just wondering if you have had better luck with aluminum since this video. Since my machine is very similar I was wonder if you had some good speed/feeds and doc you could share
I haven’t actually - life has gotten in the way and I think the z has too much flex. I have some c-beam that I thought about replacing it with just so there’s 2 sets of wheels to prevent forward/backward flexing. Really excited to try Alex Lee’s modified spindle mount.
I’m super excited to try it out let me know how it goes if you get yours done before I get mine and I will do the same. A buddy with an Ox suggested that I put eccentric spacers on all 6 wheels that make up the z movement. He did it on his and said it made a whole world of difference in being able to get the same pressure on all the wheels for the z axis
That’s a pretty neat suggestion. I cant recall right off the top of my head but seems you could get the correct size drill bit and use the current holes as pilots. This should allow for pretty accurate drilled holes as long as you did them on a drill press.
Dont give up yet though @Alex_Krause you will get there, I’m sure of it.