Flange length with flat pattern control

Today I figured out some cool math others may want to use. Attached is a screen shot.


My goal was to have the flat pattern of the flange always be a fixed distance no matter what the thickness or bend radius of the part is. The screen shot shows the math to accomplish a 1" flange if the angle is 90 deg and K=0.33. The gage (Radius and thickness) can be anything.


This math only applies to a flange created as an inside flange w/ and outside dimension.


An ER is in the process of being started that will add this as a 3rd option for flange length when creating a flange. The Icon would look something like the second attachment.



Betreff: Flange length with flat pattern control

Hi @12GAGE



if I have understand it correctly, what Your approach will be, then what is about the PZL formulars like ISOTable

If I take  lookk into the ISOtable.txt and would change all bend values with the same value, doesn't be this what You want.



Much easier I can imagine is, to change the custom macro so that it only will give one and the same value for Your bend without having any influence by radius or thickness





Betreff: Flange length with flat pattern control

[ Edited ]

I want the distance from the bend line to the end of the flange to be a constant. No matter what thickness or bend radius. At least some of the time. I need that option. The formula is the only way I have found to get that done.


In reality the bend radius is a funtion of the machine being used, the thickness and material. I have spent years refining the values based on feedback from the people operating the folding and break machines. Also the length of the bend comes into play. For our most commong material (12 gage carbon steel) I have two different radius. One for parts under 18" and one for parts over 18". And that's on just on our folder.


That a different piece of the puzzle. 


Say you design a part with whatever gage settings. When done you measure the distance from the bend line to to the edge of the part. I want that to be say 1", no matter what gage is used.


Say you have T=0.1046, and R =0.11" then the bend allowance is 0.202. divide that by two and that represent the differance between the stick out and the flange length. But that relation changes for every thickness and bend radius. The formula solves that for me. Then when I edit the gage, I still get the desired stick out.



Betreff: Flange length with flat pattern control

If you used the "bend" command instead of "flange" you can simply dimension the bend line from part edge at 1". plus you can select location of bend, left, right or centerline of sketch used, (obviously ouyd want c/l).  This 1" dimension should then be in the variable table. 



Betreff: Flange length with flat pattern control

[ Edited ]

If the flange was on a tab, I work that way often, But when the flange if from another flange, and the previus flange and tab are driven from planes, that does not work. The previus flange design is already working from other variables.





I attached another PDF to show the desired result. I want to keep the stick out 1" for bends 1 and 2 even after I select a new gage of materail w/ a different thickness and bend radius. This allows the folder operator to check the part size and back gage before folding. Everything is runs of one quantity. the folder has to be manually programmed each time we fab a tank. Some days are over 50 setups of the folder.