What grade aluminum do you guys use? And where do you get it?

[slickrick]

I am thinking of using 6061 T6. Is there any reason to use something different?

Also, has anyone found a good place to get aluminum? I have a place around me that might have assorted scrap pieces, but I dont want to have to search through their bins all the time.

Anyone know of any reasonably priced places online?

And I'm talking square pieces.

Thanks

[LazyMan]

For most of my parts I use MIC6 tool and jig plate. Its cast aluminum plate that has been machined very flat. Also it does not distort when you machine it. I think for most cnc applications that dont need high impact strength Tool and jig plate is ideal.

It costs the same as regular aluminum.

I get it from Metalexpress.net

[Cartierusm]

Just beware that although aluminum looks all nice and clean and square most aluminum is not flat and square. I don't know about the aluminum LazyMan is talking about but it sounds good.

[LazyMan]

Heres a link on MIC6 which is made by alcoa

http://www.alcoa.com/mill_products/n...81&prod_id=619

It's a good option if you dont have a mill. I used it to build my router and used T6061. For sqaure parts that were larger than 1.5 inches as MIC6 doesnt come thicker than 1.5 inches.

[mc-motorsports]

all depends on what you want to make, what is the application? Bendable? Weldable? Impact streangh? Need to anodize it?

www.mcmaster.com is where I get small quanities for small jobs or prototyping, just because I can order and have it shipped in next day, as apposed to calling the sales reps and having to pick it up. Other than that, local supply, spee-d-metals or Lake Erie Iron. Speed has a website, but thier internet orders are lacking.

[slickrick]

Thanks...

I stopped by a recycling place yesterday to see what they had, and they had a pretty big selection of scrap aluminum. Lots of blocks, and quite a bit of plate. Everything was $3.00 a pound no matter what it is.
The only problem is that I need to get all my sizes I need and search for each piece separately.
The other problem is, that I am going to manually have to cut all my pieces, and mill them to the thickness I need by hand.
Once I get the first one made, making another won't be as difficult.

[ImanCarrot]

Remember extruded ally will machine differently to cast. I find that if I machine extruded flat then unclamp it from the mill it goes "boing" and bends. So I clamp it upside down, re-skim it and it goes "boing" again when I unclamp it. Even skimming the stuff with stress free mounting still gives distortion due to internal stresses.

I only use L111 aerospace grade cast ally- THAT doesn't go "boing".

[slickrick]

Originally Posted by ImanCarrot Remember extruded ally will machine differently to cast. I find that if I machine extruded flat then unclamp it from the mill it goes "boing" and bends. So I clamp it upside down, re-skim it and it goes "boing" again when I unclamp it. Even skimming the stuff with stress free mounting still gives distortion due to internal stresses. I only use L111 aerospace grade cast ally- THAT doesn't go "boing".

When you say "Boing".....how much does it spring out of your tolerance?

[Geof]

Originally Posted by ImanCarrot ...."boing"...

Could you quantify a boing? Please.

Is it something on the order of a Barn?

[ImanCarrot]

lol

The approximate level of "boinging" is of the order of 10 fringes or so, measured using an interferometer operating at 633nm wavelength.

This equates to *mumbles and counts on his fingers* erm... 3165nm or just over 3um. In old money, that's 0.00012".

Mind you, that's with a roughing cut of 0.020mm depth (0.0008"), I dare say the level of "boing" would increase with deeper cuts.

The "boinging" seems independent of feed rate which is roughly 20mm per min (0.8ipm) at 6500 rpm.

Hmm, I might do some experiments to see if the "boinging" varies exponentialy or linearly as a function of depth of cut... when I get some time!

[Geof]

So a Boing is about the same order of magnitude as a Barn.

My experience is that aluminum plates boings depending on how much in total is taken off, not the depth of each pass. Very often a light skim cut just cleaning up the surface and maybe leaving witness marks at the low spots will hardly boing at all; this is what you must have been doing if your 0.0012 is correct. Take off about .2" on a piece of 1" material and you can get 0.02" or more over 12 inches. The annoying part is that you cannot simply machine the same amount off the opposite side and have it come straight; it can go every which way and finish up wavy.

[ImanCarrot]

Exavtly what I found- there seems to be no logical pattern to the boing, it, as you say, goes all over the place.

I've also noticed that after coating at high temperature plate ally will boing a hell of a lot.

That's why I stick to cast L111. Nice ally. *pats a lump of L111 on the head*