Why does a swept flange (conical option) give a slightly different outcome to the same form (conical) than the lofted bend (formed opition) when flattened?
The flats from swept and lofted bends are approximations.
Those shapes as modeled are not attainable on conventional press brakes.
Thank you for your response. The cones are going to be rolled. Is one not anymore suitable than another for conical forms then?
There was around 5-6mm difference in the length of the flattened profiles.
I would rather use lofted bends as this is more co-operative when flattening certain features i need to be laser cut in the flattened state. However
if neither are particularly accurate +-1mm then this is not really much help.
try this method instead
I deleted my original response, so if anyone received an email suggesting I was a moron please disregard. I was unable to get a swept flange flat pattern model to match up to my lofted flat pattern model. Close but enough difference to bug me. I had more confidence in the lofted model so I made another model using Kenneth's method of making a thin revolve then converting to sheet metal. Using the same k-factor on each I was able to match up the flat pattern of the of the lofted to the flat pattern of the converted. The match was perfect in an assembly.
I noticed in the swept flange help there is a paragraph that states:
I suspect this has something to do with issue of the flat patterns not matching up (swept vs loft).
From this I can only conclude that you should not use the swept flange if an accurate flat is required. I did some calculating the old fashion way and found the loft and revolved thin converted to be spot on.
Added Note: Since the seam gap is not the same from top to bottom (to be expected) some weld fixturing (and allowing for srinkage) may be required but difference is minimal.
Thank you both for the responses.
The lofted bend for pure conical shapes it is.
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