Dimensioning Sheet Metal Bends

Figure 3 because the bend line shifts after forming the edge to inside surface dimension will be greater than the edge to bend line dimension.

Dimensioning sheet metal bends.

Bend angle 1 degree. As one who daily works with sheet metal design and fabrication use outside flange lengths for several reasons. The diagram shows one such mechanism. Refer to the chart for values for folder as well as various press brake tooling combinations.

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. Bend length 0 010 0 25mm. Minimum sheet metal flange bend length 3 x sheet thickness bend radius. Use the minimum bend dimension values in the charts below for your minimum closeness of cutout to a bend.

Sheet metal stretches when it bends is an oversimplification. Minimum sheet metal flange bend length is required to avoid cracks in the bending area. Geometry of tooling imposes a minimum bend dimension. Press brake bend length 0 010 0 25mm per bend for controlled dimension.

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. 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. Bends specified as angles may be toleranced at plus or minus one half. 5 edge distortion an exaggerated example of edge deformation is pictured in figure a below.

Folder bend length 0 010 0 25mm per bend for controlled dimension. No worries of forgetting a material thickness along the way 3. When designing parts for laser cutting one should not make holes smaller than the thickness of the material. Bends in sheet metal are manufactured using sheet metal brakes.

Avoid large sheet metal parts with small bent flanges. 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. Bends on the same plane should occur in the same direction. A 1 degree tolerance on all bend angles.

Form height to thickness ratio to determine the minimum form height for sheet metal use the following formula. When you figure flat pattern length you simple add up all the outside flanges and subtract the bend deductions. It shall be equal to three times of sheet thickness plus bend radius. The basics of applying bend functions the fabricator november 2012 by steve benson explains it in detail.