If the radius of bend is too small, stresses and strains weaken the metal and may result in cracking.Ī minimum radius of bend is specified for each type of aircraft sheet metal. The minimum radius of bend of a sheet of material is the sharpest curve, or bend, to which the sheet can be bent without critically weakening the metal at the bend. The radius of bend of a sheet of material is the radius of the bend as measured on the inside of the curved material. Other factors that must be considered when making straight line bends are bend allowance, setback, and brake or sight line. Generally speaking, the thinner the material is, the more sharply it can be bent (the smaller the radius of bend), and the softer the material is, the sharper the bend is. When forming straight bends, the thickness of the material, its alloy composition, and its temper condition must be considered.
