Sheet metal stretches when it bends is an oversimplification.
Dimensioning sheet metal bends.
Folder bend length 0 010 0 25mm per bend for controlled dimension.
Form height to thickness ratio to determine the minimum form height for sheet metal use the following formula.
Bends on the same plane should occur in the same direction.
5 edge distortion an exaggerated example of edge deformation is pictured in figure a below.
When designing parts for laser cutting one should not make holes smaller than the thickness of the material.
Bend length 0 010 0 25mm.
Press brake bend length 0 010 0 25mm per bend for controlled dimension.
Bend angle 1 degree.
D 2 5t r see below the height can be less but it required secondary operations and is far more costly.
As one who daily works with sheet metal design and fabrication use outside flange lengths for several reasons.
The basics of applying bend functions the fabricator november 2012 by steve benson explains it in detail.
In low carbon steel sheet metal the minimum radius of a bend should be one half the material thickness or 0 80 mm 0 03 inch whichever is larger.
This is a common occurrence when manufacturers receive a sheet metal layout dimensioned in the flat pattern.
Bends specified as angles may be toleranced at plus or minus one half.
Minimum sheet metal flange bend length is required to avoid cracks in the bending area.
Avoid large sheet metal parts with small bent flanges.
Sheet metal parts with a minimum of 0 9mm to 20mm in thickness can be manufactured.
These dimensions may seem helpful but after your manufacturer makes bend deductions based on their capabilities and other bending factors your dimensions will become unusable.
The best way to measure a hem from the outside radius to the hem edge is with a surface plate angle block and a height gauge.
Geometry of tooling imposes a minimum bend dimension.
It shall be equal to three times of sheet thickness plus bend radius.
A 1 degree tolerance on all bend angles.
No worries of forgetting a material thickness along the way 3.
Minimum sheet metal flange bend length 3 x sheet thickness bend radius.
Upon close examination of the bends we find that the sheet metal stretches on the outer surface and that the inside surface seems to shrink.
The diagram shows one such mechanism.
Use the minimum bend dimension values in the charts below for your minimum closeness of cutout to a bend.
Refer to the chart for values for folder as well as various press brake tooling combinations.
