aircraft aluminum tubing bend radius chart

The TDW is less than the sum of mold line dimensions since the metal is bent on a radius and not to a square corner as mold line dimensions indicate. Finding the TDW is necessary to determine the size of material to be cut. Total developed width (TDW)-the width of material measured around the bends from edge to edge. Open angle-an angle that is more than 90° when measured between legs, or less than 90° when the amount of bend is measured. It is equal to the base measurement (MLD) minus the setback.Ĭlosed angle-an angle that is less than 90° when measured between legs, or more than 90° when the amount of bend is measured. Sight line-also called the bend or brake line, it is the layout line on the metal being formed that is set even with the nose of the brake and serves as a guide in bending the work.įlat-that portion of a part that is not included in the bend. The K-factor must be used for all bends that are smaller or larger than 90°. The majority of bends in sheet metal are 90° bends. When a part has more than one bend, setback must be subtracted for each bend. The setback dimension must be determined prior to making the bend because setback is used in determining the location of the beginning bend tangent line. In a 90° bend, SB = R + T (radius of the bend plus thickness of the metal). Setback (SB)-the distance the jaws of a brake must be setback from the mold line to form a bend. However, the amount of error incurred is so slight that, for most work, assuming it is at the center is satisfactory. For calculation purposes, it is often assumed that the neutral axis is located at the center of the material, although the neutral axis is not exactly in the center of the material. This thinning of the bend area moves the neutral line of the metal in towards the radius center. After bending, the bend area is 10 to 15 percent thinner than before bending. Neutral axis-an imaginary line that has the same length after bending as it had before bending. All the space between the band tangent lines is the bend allowance. Minimum bend radius charts can be found in manufacturer’s maintenance manuals.īend tangent line (BL)-the location at which the metal starts to bend and the line at which the metal stops curving. Always use a Minimum Bend Radius Table to determine the minimum bend radius for the alloy that is going to be used. The minimum bend radius depends on the temper, thickness, and type of material. The bend radius is measured from a radius center to the inside surface of the metal. The bend allowance may be considered as being the length of the curved portion of the neutral line.īend radius-the arc is formed when sheet metal is bent. Bend allowance (BA)-refers to the curved section of metal within the bend (the portion of metal that is curved in bending).

Aircraft aluminum tubing bend radius chart