Bow and Twist in 5083 Armor Aluminum Need Help

[Mr. Wizzard]

So I have some bars to machine.

 

They start out at roughly 1.5" x 2.0" x 34" long.

 

I have to mill out a step roughly 1.2" x .75" down the entire length and it's bowing and twisting to hell.

 

i'm going the rough, flip, rough, flip, fuzz, flip, fuzz, flip method and was wondering if anyone has any better ideas?

 

TIA!!!!!!!!!

[K2csq7]

When all else fails, I just use Magic.

[Mr. Wizzard]

If it comes down to it, I'll have to.

[koko76]

Not super familiar with the alloy but would it be possible to normalize and then re heat treat to relieve the stress?

[Hardmill]

 

 

i'm going the rough, flip, rough, flip, fuzz, flip, fuzz, flip method and was wondering if anyone has any better ideas?

 

TIA!!!!!!!!!

 

Sometimes we just do what we gotta do.

 

Light faster cuts will reduce the stress put into the material also.

 

 

 

 

 

 

 

 

 

 

 

 

 

PEACE

[Mr. Wizzard]

Thanks for the tips/confirmation, guys.

 

As far as stress relief, anything involving heat is out of the question as everyone is afraid of it altering the ballistic properties of the material. I found some things online that i know nothing about, but time constraints don't allow us to try them anyhow: vibratory stress relief and sub-harmonic stress relief. Oh well.....

 

To Hardmill, yep. That's the road i gotta go for now. Rough, flip, rough, flip, size, flip, size, flip.......

 

So far, it's working. I'm sizing and milling all features and keeping the bar relatively flat through those processes. I save the big step for last and that's where the .050-.070 bow is coming from. At least, for now, they tell me the bow will get clamped down when the part is bolted up, so it is acceptable. I just don't like it, cause it ain't pretty.