Sheet Metal Development Length Formula

By replacing initial length leg length 1 and 2 in the above equation we can calculate the bend allowance as follows.

Sheet metal development length formula.

Punch edge radius in. Die edge radius in. The length of the median plane is the unfold length which can be obtained by the following formula. Cells on the right will output the desired values.

Bend allowance ba the amount of added to the sum of the two leg lengths to obtain the flat pattern length. Material thickness mt the gauge of the material in decimal form. Ultimate tensile strength psi. If you have a sheet metal bending product as shown in above picture with two legs of length x and y and you unbend it you will see that total length of the unbend sheet will not x y rather the length will be x y ba.

Bend deduction bd the amount removed from the sum of the two flange lengths to obtain a flat pattern. The length of the arc for this scenario can be calculated as. Where ba is bending allowance. Length of the flat blank in preparation for bending.

With this free online tool we quickly get the sheet metal bend deduction and therefore the sheet metal blank initial flat length from the finished part measurements. Where r is the radius of the arc on the neutral axis. Transition patterns available flat pattern segments lobsterback bend elbow ellipsoidal dome head tee offset tee square and rectangle to round frustum cone. Sheet metal development calculator is a really simple tool for calculation of development of a sheet metal part.

Bend deduction is equal to the difference between the total sheet metal length after bending and flat length. Calculate the setback and then subtract it from the sum of two outside dimensions as follows. Therefore after bending total sheetmetal part length a b is greater than sheet metal flat length. We know that ba is the length of the arc on the neutral axis.

You only have to insert interior angle flange lengths k factor inside radius and material thickness. L a x b x α 360 2π r t1 1 2 here where α 90 the result is l a 1 57 r t1 x 1 2 b. The formula for this is sb 43r 1 372t r the radius on the inside curve of the bend.