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oxford
05-07-2018, 07:46 PM
Does anyone have any experience machining 1100 alloy aluminum? I have a job coming up where I need to OD turn some 2" barstock down to 43mm, face both ends, and drill a 2mm hole 25mm deep in one end. I have never worked with this alloy before. Any tips on speeds/feeds and lubricant? I am doing this on a manual lathe that does not have flood coolant. I was planning on using a ccgt insert for turning the OD.

ACHiPo
05-07-2018, 08:00 PM
Ok, I'll qualify my response first by saying I've never machined 1100 (basically pure) aluminum BUT I did have success machining oxygen free high purity copper which cuts like taffy, so I'm guessing they're similar. After roughing the copper to shape, I used a shear tool that I ground myself from a HSS blank to finish the part. Pretty easy tool geometry, decent finish. Good luck and post your results.

oxford
05-07-2018, 08:05 PM
I also forgot to mention that tolerances are pretty loose on this for I know the OD, probably the length as well. I am a little worried about the 2mm hole though.

MattiJ
05-07-2018, 08:56 PM
I also forgot to mention that tolerances are pretty loose on this for I know the OD, probably the length as well. I am a little worried about the 2mm hole though.

Buy good, polished hss drills and peck like crazy with good aluminium cutting fluid.

I have drilled some 30mm deep and 1mm dia holes to "pure" aluminium and I can admit that I broke quite a few drills before getting it right..

754
05-07-2018, 10:10 PM
I hope I am wrong but expect a lot of piling up buildup on tool , you must keep stopping to remove.
I had a big AL round, I was taking 5 plus inches out the middle, it must have gotten annealed back to 0 temper.
Worst crap I ever turned.
Took so long I would have been better off buying another piece.

Toolguy
05-07-2018, 10:20 PM
Use a spot drill, then a parabolic flute drill. Use Tapmagic for Aluminum for drilling and turning. I put some in a spray paint can lid and brush it on with an acid brush just like any cutting oil. Should go pretty well.

oxford
05-12-2018, 05:22 PM
Just an update, this job went ok. 1100 is certainly different than 6061 or 7075 though. I used the tapmagic aluminum and the parabolic drill mentioned above for drilling. I ended up drilling them in the mill since there isn't a drill chuck on the lathe at work to hold that small of a bit. Probably better anyways as I could get more spindle speed out of the mill and the a little more sensitivity out the quill handle vs the tailstock wheel. I did have to stop the spindle and clear the chips off the drill bit by hand as they wanted to load up even with small pecks.

The turning went ok as well with the ccgt insert but I had to take a very light cut and basically flooded with wd40 to get a nice finish. I think this job would have gone a whole lot better with flood coolant.

754
05-12-2018, 09:41 PM
I warned you.. now there is two of us that know what it's like. .
Not sure where you got it, but I imagine it being very hard to find, compared to 6061.

JRouche
05-13-2018, 12:38 AM
Machining, turning. Everyone already knows 1100 series is an issue. What is your fix?

MattiJ
05-13-2018, 03:24 AM
I hope I am wrong but expect a lot of piling up buildup on tool , you must keep stopping to remove.
I had a big AL round, I was taking 5 plus inches out the middle, it must have gotten annealed back to 0 temper.
Worst crap I ever turned.
Took so long I would have been better off buying another piece.

If I recall correctly the buildup was only problem for finishing cuts. Roughing cuts with plenty of speed and feed and the chip is "flowing" off the workpiece pretty nicely. Chip control was very difficult as it didn't want to curl or break, chip is more like thick aluminium bar/wire. More aggressive chip breaker profile just fills/welds up with aluminium.

oxford
05-13-2018, 09:19 AM
I called around to a few places to find the material, up to 1/2” rod should’t be a problem finding but bigger rounds are more of a problem. It ended up coming from a place in Long Island NY. They had in stock and we had it 2 days later.

1100 was actually second choice material, it was supposed to be 1235 but that seems unobtainable in anything other than sheet and mostly foil.

Build up on the lathe insert did not seem an issue but like mentioned above it was just like one big flowing chip coming off. I actually started off with ccmt insert and it didn’t seem a whole lot different than the ccmt. No issues with the finishing cut, it came off like a fine string. On deeper roughing cuts it did push a major burr along with the chip.

One thing that did surprise me was on the roughing cuts where the chip was coming off a rubbing the edge of the insert it wore grooves into the insert. This was only a .040” DOC and maybe 2 to 3 passes across a 2 foot long had to do this.

garyhlucas
05-13-2018, 11:15 AM
Oxidation of the pure aluminum forming aluminum oxide, the stuff grinding wheels are made from?