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Aluminum Material Selection for Panels With Bends to Be Anodized

goldenfab

Aluminum
Joined
May 25, 2016
Location
USA Prescott , Arizona
I picked up a job to make some enclosures. Some of the thick parts are machined from 6061-T6. The thinner panels are designed to be 0.125" thick with the sharpest bends having a 0.125" inside radius. From what I could find 6061 with a T6 temper would be trouble to bend. I'm using a press brake I made - bottoming type with 90deg V die on the bottom and 0.125" radius upper die. The die opening is only like 6x (if that) the material thickness - needed to get the close bends for the hat shape. I suggested we use a -O temper and made some prototypes with it. The bends came out great but machining a cutout with a corner radius is terrible because it is so soft. My customer wants to hard coat anodize all the parts to match hence why choosing 6061 for the panels. The next plan is to try 6061-T4 for the 0.125" bent sheets.

Can anyone suggest a better idea?

Thanks,
Adam

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JNieman

Titanium
Joined
Nov 12, 2011
Location
Greater St Louis Area
Can you laser or waterjet cut the blanks? Those processes shouldn't care about the temper of the aluminum.

Nor would they help bend them....

OP: 6061 sucks to bend, for sure, but if you can buy it in the O state or a temper of lower hardness, it can be done smoothly enough.
 

Dan from Oakland

Titanium
Joined
Sep 15, 2005
Location
Oakland, CA
5052-H32 is what I would use for any panels that are going to be formed. Won't crack, is easily welded and will anodize with no issues. It can be a little on the gummy side to machine, but not impossibly so.
 

JNieman

Titanium
Joined
Nov 12, 2011
Location
Greater St Louis Area
5052-H32 is what I would use for any panels that are going to be formed. Won't crack, is easily welded and will anodize with no issues. It can be a little on the gummy side to machine, but not impossibly so.

I was hesitant to suggest another alloy because I didn't know if they would match perfectly when anodized. I suppose a simple experiment would suffice. I also don't know enough about anodizing - can you put different alloys into the same batch, or are there different processing requirements to anodize different alloys?
 

goldenfab

Aluminum
Joined
May 25, 2016
Location
USA Prescott , Arizona
Can you laser or waterjet cut the blanks? Those processes shouldn't care about the temper of the aluminum.
I don't think those processes would be good at making a 0.125" fillet on the inside cut edges? Either way having to sub out these parts is probably not worth the trouble for this case.

OP: 6061 sucks to bend, for sure, but if you can buy it in the O state or a temper of lower hardness, it can be done smoothly enough.
Yes the 6061-O that I have bent great and I'm really happy with the appearance of the bend radius. I'm hoping 6061-T4 comes out close to as good. I just ordered some this morning.

5052-H32 is what I would use for any panels that are going to be formed. Won't crack, is easily welded and will anodize with no issues. It can be a little on the gummy side to machine, but not impossibly so.
I assume it machines better than 6061-O? Matweb lists a machinability index for 6061 but not for 5052 and I can't find any comparisons anywhere else?

I was hesitant to suggest another alloy because I didn't know if they would match perfectly when anodized. I suppose a simple experiment would suffice. I also don't know enough about anodizing - can you put different alloys into the same batch, or are there different processing requirements to anodize different alloys?

This is a big question for me as I do not yet have experience with it which is why I went with 6061-O.
 

JNieman

Titanium
Joined
Nov 12, 2011
Location
Greater St Louis Area
I don't know how accommodating your supplier would be, but maybe send them a few 'coupons' to run through the same batch and see what happens. They might do it for free if they're running a job that the coupons can ride along in.
 

robert123

Stainless
Joined
Apr 8, 2012
Location
AR, USA
If you use different alloys, they will almost certainly be different colors after anodize. It is usually recommended that different alloys not be anodized at the same time. I assume this is due to differing conductivities and crystal growth rates though it can be done.

If strength is not important, perhaps you could use 6061-T6. Make your cutouts, anneal, and then bend. Or if you are making the cutouts after bending, heat the bend area with a torch to soften only the bend areas. It might take a little experimentation.

You can find charts online that give minimum bend radii for given material alloys and thicknesses. This should give you a good idea if 6061-T4 will work for bending. For machining, I would think it would be OK. It does have reasonable strength, but I've only cut it on a water jet before.
 








 
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