Sheet Metal Bend Relief Formula

Refer to the chart for values for folder as well as various press brake tooling combinations.

Sheet metal bend relief formula.

Consider a sheet with a 20 mm thickness and a length of 300 mm as shown in figure 1. Coining one of the three types of bending for sheet metal where the punch penetrates into the sheet metal under high tonnage forming a consistent bend. One benefit of a bend relief is that it makes the part easier to produce. Crowning the deflection along a bend.

The force must exceed the material s yield strength to achieve a plastic deformation. 60 90 and 120 and we will calculate k factor bend allowance and bend deduction for them. This is done through the application of force on a workpiece. A 1 degree tolerance on all bend angles.

Box bending the process of bending a 4 sided sheet metal box. The bend allowance and bend deduction are two measures that relate the bent length of a piece of sheet metal to the flat length. Bending is one of the most common sheet metal fabrication operations. Bending is a manufacturing process that produces a v shape u shape or channel shape along a straight axis in ductile materials most commonly sheet metal.

Most sheet metal materials will conform to the calculations. The bend allowance describes the length of the neutral axis between the bend lines or in other words the arc length of the bend. Commonly used equipment include box and pan brakes brake presses and other specialized machine presses typical products that are made like this are boxes such as electrical enclosures and rectangular ductwork. When designing parts for laser cutting one should not make holes smaller than the thickness of the material.

To eliminate this a bend relief is added so the edge of the sheet metal is perpendicular to the bend. Also known as press braking flanging die bending folding and edging this method is used to deform a material to an angular shape. Sheet metal parts with a minimum of 0 9mm to 20mm in thickness can be manufactured. The following illustration shows the equation calculation for determining the bend allowance when forming sheet metal.

We are going to review three bending scenarios with three different bending angles. This page also includes a link to a on line sheet metal bend allowance calculator. Understanding the bend allowance and consequently the bend deduction of a part is a crucial first step to understanding how sheet metal parts are fabricated. As this happens you gain a small amount of total length in your part.

If it is ok for the metal to rip the minimum bend relief is zero. Use the minimum bend dimension values in the charts below for your minimum closeness of cutout to a bend. The diagram shows one such mechanism. Sheet metal calculator bend allowance equations and calculator.

In general a minimum bend relief is equal to the material thickness plus the inside bend radius. Geometry of tooling imposes a minimum bend dimension. Bends in sheet metal are manufactured using sheet metal brakes.