Sheet metal neutral factor help 2

[ALiebeck]

Hello all.
I have been using SE V19 for a few years now, but this is the first time i have needed to ask for help on a forum.
Does anyone know what the neutral factors are for various gages of aluminum and Stainless steel?
I am designing parts using .059 th al, and 0.000 bend radius.

Any Links or advice would be greatly appreciated

Thanks
Aaron

Windows XP Pro
SE V19

 

[PatCouture]

Are you sure you're able to get a 0" bend radius? I've never seen that.

For the neutral factor It depends greatly on the precision you need to achieve. I'm using a lot of sheetmetals part that are then welded together and a .33 neutral factor is enough for me. But that can be different if you need more precision.

Usually you can find some info from the manufacturer of the bending machine that you use. At least it's a start.

Patrick

 

[karmoh]

Hi,

Patrick is right, it all depends.
I'm primarily a designer of sheet metal products and fabrications ranging from 0.5mm (.0196) to 10mm thick. The bend radius you specify is only possible if form tooling is used and then it's virtually impossible to have a zero bend radius. Therefore traditional bend allowance formulae will not be sufficient
For aluminum of 1.5mm (0.059) the neutral factor differs from fabricator to fabricator. For 0.059 (16 gauge) the neutral factor can range from 0.20 to 0.26 depending on the tooling used, with a range of bend radii of 0.5mm to 0.8mm.
I have a spreadsheet that calculates these things but in your case you’ll need to talk to a toolmaker to determine your true requirements.

 

[Gemnoc]

I concur with karmoh, many factors apply, even the aluminum or stainless steel grade I think. At the shop I used to work, neutral factor for stainless steel would vary wildly from 0.32 to 0.49 for 6 different gages. I based my SE material library on bend deduction values given by the operators, and it worked very well.

If you need precision, you definitely need to get bend allowance or bend deduction values from the shop that will fabricate your pieces. You can then determine the neutral factor easily in Excel.

BTW To my knowledge, there is no 0.059" thickness for aluminum. The aluminum chart has 14ga alum at 0.064". 16ga stainless steel is 0.0625", and 16ga mild steel is 0.0598". See chart here: Gauge and Weight Chart

 

[Gemnoc]

(it's a pity this forum doesn't allow post editing!)

Of course, those gauge values are nominal. Tolerances are involved, I've often measured material that was up to 0.005" thinner than the nominal value.

 

[donyoung]

> To my knowledge, there is no 0.059" thickness for aluminum

1.5mm = 0.059" (0.05905511.. exact) ;-)

dy

 

[Gemnoc]

@ Don Young

Well, I should have added, "in North America". At least, in 16 years working in metal fabrication, I've never seen sheet metal provided in metric gauges in Canada & USA. The closest to 1.5mm is 0.064" (or 1.63mm), as per the chart I linked...

 

[ALiebeck]

Hey guys,

Thanks for all the advice. I have been discussing this with an "old time" sheet metal die maker that works part time for us. he has told me the exact same thing that you have said here. I guess my statement about a 0" bend radius was incorrect. What i should have said is that all the bends are "tight". Of course the differences between the finished part and the print are kind of subject to how sharp the form bar is.
it looks like we have this pretty much figured out.
Thanks again for the help.

Aaron

 

[bgy]

My breack operator ask me to adjust the neutral factor as follow:

aluminum: 0.42
carbon steel: 0.44
stainless steel: 0.46
for hem feauture: 0.56 up to 0.6

But each metal shop got his owns depending of tooling.