Xometry Europe Blog

In sheet metal fabrication, curving sheets according to a specific bend radius is one of the most common operations used to create flanges, curls, seams etc. Moreover, bending imparts much strength to the sheet metal compared to their flatter counterparts. For example, an aluminium sheet bent into a V cross section will be much stiffer and stronger than the same flat sheet. Bending a metal sheet usually comes with a set of calculations and design requirements. The bend's outer edge would crack if it exceeds the minimum bend radius which is typically specified according to the metal sheet thickness (t) like 1t, 2t, 3t etc. A typical recommendation is 1t for all sheet metal parts, which means the smallest bend radius should be at least equal to the sheet thickness. For example, if the thickness of the sheet is 2mm, the minimum bend radius should be 1t which is 2mm. What is the right bend radius for sheet metal? Below is Xometry's minimum bend radius reference table which is based on theoretical sheet metal gauge thicknesses. Thickness of the sheetMinimum bend radius1–6 mm1 time the thickness of the sheet6–12 mm1.5 times the thickness of the sheet12–25 mm2-3 times of the thickness of the sheet For specific thicknesses, you can refer to the reference table of the sheet’s material. Here is an example of such a reference table for Steel 1.0038 / S235JR below: Bend Orientation Rules The next important consideration while designing sheet metal parts is the bend orientation. In order to save time and money, the bends originating from the same plane should be oriented in a similar direction to avoid the reorientation of the part. Moreover, keeping a consistent bend radius across all the bends results in decreasing the costs of sheet metal as all the features can be produced with the same setup and tooling. It is to be noted that the bending accuracy is inversely proportional to the thickness of sheet metal. In order to achieve a great bend precision, we recommend decreasing the sheet thickness. As an example, let us take the two images below to explain the correct bend radius for a 1mm thick sheet (top) and the correct bend orientation for two bends in a similar plane (bottom). Correct Bend Radius Correct Bend Orientation Designing for sheet metal with the right bend radius As minimum bend radius is one of the most important things when it comes to sheet metal machining, we recommend expert advice even from the initial design in order to get an accurate part and avoid unnecessary expenses. At Xometry Europe, we offer highly accurate sheet metal services as well as design consultancy services (DFM). Through our Instant Quoting Engine and our network of over 2,000 manufacturers, we ensure that you experience a seamless part production process, from quoting to doorstep delivery.