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Fluting and Re-Fluting

RV701775

Active Member
I was fluting a large E-609 counterbalance rib that was a bit challenging to get flat and aligned. This resulted in me fluting, unfluting slightly by using the fluting pliers in the opposite direction and refluting to my frustration.

My question is how many times can you flute and reflute without damaging the rib? I would say that some I fluted and refluted 2-3 times, finally getting it aligned properly, but is the rib prone to cracking at this point due to work hardening?
 
If you fluted, then totally flattened out, then refluted, I would say that’s about the limit where I would be comfortable. There’s guidance on people making a dimple, then flattening out and going the other way. They only get one shot (two dimple directions) and if they go for a third dimple back to the original direction, it cracks. I think the micro a mount that you are moving the flutes, you would get a lot more than 2 or 3 adjustments before you get problems. Try taking some scrap and flute back and fourth to see when you get cracks
 
Howdy Mike. If you flute in the wrong place; like where you find you need to drill a hole or the flute somehow interferes with another part; you can also use a pneumatic squeezer, (if you have one) to flatten the flute.

Fluting induces stress in the part just like bending or dimpling. I will always bend my angles in aluminum slightly further than the required amount, then hand bend it slightly in the opposite direction to relieve the stress and set the angle. The same can be done with fluting. I will flute my parts slightly more than necessary, then hold the part on both ends, put my knee in the middle and slightly pull it in the opposite direction to relieve the fluting stress and get it straight. With practice, you'll see just how effective this actually works and how perfect you can straighten a part.

Try sneaking up on the flutes a little at a time; flute where required just slightly, then go back over those same flutes and squeeze a little more. Once the part is slightly curved in the opposite direction, unbend it by hand to relieve the stress and get it straight.
 
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