
#13878 
If any such thing exists.
I mean I want to bend 1mm sheet metal to 90 degrees with a bend radius of 2mm. A 4 foot wide piece.
And I want to build the bender to do it.
I need to know how much force will be required to make that bend.
How much force to be exerted on moving the movable arm of the bender.
How much force will be exerted in at the clamp of the bender dictating how strong it must be.
Seems to me such information would be handily kept in tables or at least in some hand formula.
Anyone know of such?
 This topic was modified 11 months, 2 weeks ago by arthur brogard.
#13894 I have found the excellent page of formulas: http://sheetmetal.me/formulasandfunctions/bendallowance/
but it doesn’t cover the case of simply bending sheet metal with a manual bender or folder as they’re sometimes called.
It covers only press brakes, using dies.
I enquired about this elsewhere and have been informed such tables/formula do not hold for benders.
If the truth is otherwise please let me know.
A drawing of the bender problem I am trying to sort out:
#14361 the tables you found only dictate the bend allowance which is necessary to work out the flat pattern of your sheet for cutting, in order to get the desired results. bending deforms the metal in a way that the final length of your workpiece cannot be calculated from the centre or either side – it “moves”, taking the k factor into account.
what you can use, is a bending force chart. there’s one here – https://fractory.com/sheetmetalbending/. as you can see, a 1 mm sheet with a 2 mm radius needs 6 tons to bend 1 m. your bending line is 1.2 metres, so the required force is around 7.2 tonnes.
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