What Is Centerline Radius?
Often, centerline radius (CLR) is confused with the degree of bend. CLR is the distance from the center of the forming die to the centerline of the material to be bent. This distance often is overlooked, yet it is critical to achieving appropriate bend quality. Factors that affect the CLR include the material grade to be bent, wall thickness, the type of bender to be used, the application, and overall appearance required. Generally speaking, CLR dimensions produce bends with better quality and appearance to the eye. Bending materials to CLR less than two times the material diameter requires internal support of a mandrel to prevent the tube from collapsing. Rotary draw mandrel bending generally requires more expensive machinery and tooling than nonmandrel-style rotary draw machines. For this reason, be sure to review the application’s CLR carefully during the design stage, and consider the cost of manufacturing.
