Aluminum EdgeBuildUp

[hardrocker]

Hello All! Great forums, you have; hopefully, someday I can offer some worthy advice, but right now I'm on the asking side. I've surfed a bit and think this one's worthy of a unique thread:

We're making a new product (sorry if I'm vague, not high-tech on this app, but I think unique to the industry), made from the most sticky machining Al I've seen. The operation in question is drilling a 3/4" hole 3" deep. HSS drills and mills seemed to build up just being in the same room as this stuff (at which point the chips are more like tears, and I can't imagine this in a production mode). Going coolant fed TiCN coated carbide, there looks to be hope, but on our first experiment, where we didn't have the coolant pressure up and were only at about .005 tooth load, it deposited pretty good (another 40 holes at higher coolant pressure, and faster feeds didn't seem to add too much, so some hope).

The question: anything work better? Is there anyway I can run this near-dry (perhaps oil mist through the bit)? If so, how about continuous vacuum chip collection!?

Thanks!

[Eurisko]

The best way to machine gummy aluminum is not at all.

Have it heat treated.

[BobWarfield]

So are you sold on using that particular aluminum?

Could be several things to try. You don't mention how many flutes are on your cutters. 2 or 3 will be better. High helix end mills will also eject the chips better.

You say your feed per tooth is 0.005. Check out Niagara's recommendations for your application, this may not be a good value:

http://www.niagaracutter.com/techinf..._mat/6061.html

Once the chips pack in there, they eventually weld themselves to the cutter, so chip evacuation is key with aluminum. Anything you can do to improve the evac will help. For example, can you use a smaller end mill and try to get more clearance around it. Make sure your coolant or the air stream is really blasting the chips out of there.

WD-40 seems to reduce the tendency of the aluminum to weld, so look at your choice of coolants to see which one will work best as well.

Best,

BW

[hardrocker]

Originally Posted by Eurisko The best way to machine gummy aluminum is not at all.

I sure wish! But I'm afraid the material, and process [in the respect it has to be machined] were customer specs we didn't have much choice in.

[hardrocker]

Originally Posted by BobWarfield WD-40 seems to reduce the tendency of the aluminum to weld, so look at your choice of coolants to see which one will work best as well. Best, BW

2flute on everything we tried; the coolant fed drill was fairly high flute; I don't recall niagra having a 5:1 depth ratio, but I'll have to look again. Once we got the speeds and feeds up (then .015 per turn, .008 tooth load), the chip breaking and ejection was too neat: for about second it sounded like a rapid splatter of chips against the VMC walls, with a beautiful cutter sound and motor sound in the background; a second of traverse, then splatter......


WD-40?!! Awesome, I was brainstorming what to feed a near-dry op and had that one pass my mind, but never thought it might be the answer. We'll need to give that one a try. Thanks!

[hardrocker]

Looking at the Niagra site, and considering the TiCN maybe we should have been running heavier tooth load yet. I know the .005 wasn't enough: 1 long string of "chip", but then we didn't have the coolant set up to give it full pressure either, so may have been better, but doubt the chip shape would have changed.

Thanks again!

[Eurisko]

Okay, my first response might have been a little off-base...

You could try an additive in the coolant, we've used TrimSol and it definitely works (unless the aluminum is total crap) . 2% to 5% by volume. Not cheap. Not pleasant to work with, either.

[hardrocker]

Originally Posted by Eurisko Okay, my first response might have been a little off-base... You could try an additive in the coolant, we've used TrimSol and it definitely works (unless the aluminum is total crap) . 2% to 5% by volume. Not cheap. Not pleasant to work with, either.

I enjoyed your first response! But sure appreciate the lead on TrimSol; new to me. I'm still rattling the WD-40 through my mind too; this would be so nice to run near dry, but I'm not counting on it!

[joecnc1234]

I might try HSS cutters the edges are sharper than carbide and I'm assuming the material is T0 I hate it Might try calling the customer and telling them you'll give them a break on price if you can use T6. or you could use T6 then send it out to ht to bring it back to the condition they want?

[davereagan]

Hello,
I would definitely use a soluble oil or semi-synthetic, but not a true synthetic on aluminum, and no less than 8% concentration. Also, Garr Tool has a new line of endmills and drills specifically for aluminum. They have a Titanium Diboride coating with a low affinity for aluminum and I think it may be noticeably better than TiCN. I would call them and ask for a catalog and the insert on these new tools, which may still not be in the main catalog. Good luck. www.garrtool.com

Dave

[hardrocker]

Originally Posted by joecnc1234 I might try HSS cutters the edges are sharper than carbide and I'm assuming the material is T0 I hate it Might try calling the customer and telling them you'll give them a break on price if you can use T6. or you could use T6 then send it out to ht to bring it back to the condition they want?

Good idea on the HSS, I didn't find anything with the depth I wanted when I was first looking (but I was steering a bit toward carbide at the time anyway leaning on rigidity more than sharpness) - of course I'm fairly sold on coolant fed for this application narrowing the options too.

A pecking sequence is an option, but for production, I don't like it - also at 3" deep if I can find a combination that works on a pecking sequence, I'm pretty sure it will do 3" straight down (fewer deccelleration points for potential build up too)

Sure glad I'm not the only one on the planet thinking there has to be an alternative; but Apps Eng was pretty addamant. Truth be told, I really don't want anymore variables at this point either. Of course, even if I could get the raw material heat treated (I don't believe this stuff takes heat treatments well anyway though), the processes prior to machining it would mess that up pretty good (it gets baked to near melting a couple times and slowly cooled).

[hardrocker]

Originally Posted by davereagan Hello, I would definitely use a soluble oil or semi-synthetic, but not a true synthetic on aluminum, and no less than 8% concentration. Also, Garr Tool has a new line of endmills and drills specifically for aluminum. They have a Titanium Diboride coating with a low affinity for aluminum and I think it may be noticeably better than TiCN. I would call them and ask for a catalog and the insert on these new tools, which may still not be in the main catalog. Good luck. www.garrtool.com Dave

A quick glance at the website looked like their lengths were a bit short for this; I may wind up going custom anyway though. That TiB2 is a new one for me; very interesting. Thanks!