good morning or evening all, we're on 2018 sp1 I'm doing some rings for rolling it doesn't seem like the k-factor is right in sw

good morning or evening all, we're on 2018 sp1 I'm doing some rings for rolling it doesn't seem like the k-factor is right in sw

Rolling and rotary folders can give the unexpected results of K = 0.25. Typically K = 0.33 to 0.5 is used.

Each mixture of machine and material can have a different K value. You must test to know what it is.

How do you test? Estimate a flat length. Then roll or bend. measure the outside dimensions. Then do the math and adjust K until it works out.

There is no way to bypass this process other than manufacture parts that are not exactly right.

steve and dennis I never had a problem with sw and k factor rolling rings I was away from sw for a while the co. I work for upped to 2018 a coworker said something was amiss so just figured i'd ask and see what came up. i don't know if I should mark anything correct I do very much appreciate the feed back thanks

Steve,

Assuming you know how the K-Factor is calculated and applied, you should be able to tune/adjust the values in your sheet metal gauge tables. In 2017 (maybe 2016?) SOLIDWORKS provide a much more comprehensive way to manage the K-Factors in sheet metal, so perhaps that's what's yielding a different result.

Steve, you need to supply more information. How about posting the part and then pointing out what seems amiss.

K-factors in SWX work very well, but the resulting flat pattern is very much affected by the value you choose for the K-factor. From my experience, most ring forming or rolling operations have a very large ratio of the IBR/thickness. Usually for any IBR/t > 5 a K-factor of 0.5 gives very accurate results. Certainly for IBR/t >10 you can use .5 (unless you have something funky going on or if you have measured results to provide a different value).

I have attached information I put together to help explain how to measure the required parameters and to calculate the K-factor for various conditions. You should be able to adapt the technique for ring rolling. Note: Most people make the mistake of assuming the material thickness is the published nominal gage thickness, but this is

rarelythe case and the thickness is perhaps the most important value in these calculations.