Standard Draw Bend Tools

BEND DIE
The bend die is the primary tool around which the tube is formed to produce a specific bend radius. Generally, the tube groove in the bend die is equal in depth to half the tube diameter. The radius portion of the bend die is equal to the required degree of bend (DOB) plus some over-bend for springback compensation.

CLAMP DIE
The clamp die is used with the bend die to grip the tube. The clamp die length matches the bend die grip section and holds the tube in place during bending. The length of the clamp die depends on the size of the tubing and the radius being bent. A surface alloy treatment and serrations are features that can be added to the grip section to ensure proper tooling grip.

PRESSURE DIE
The pressure die functions as a containment tool during bending. The pressure die provides constant pressure at tangent and follows the tube through the bend. The length of the pressure die depends on the DOB and the centerline radius (CLR) of the part.

WIPER DIE
The primary function of the wiper die is to prevent the tube from wrinkling during bending. A wiper die is required when the tube’s resistance to compression is high. H&H will recommend when a wiper die is required for a given application. H&H will also specify the material of the wiper die based on the material of the tubing being bent.

MANDREL
The mandrel is the tooling component that provides support to the inside of the tube. Its primary function is to prevent the tube from buckling and necking. Many different variations of mandrels exist. The required style and material depends on the outside diameter (OD) and wall thickness (WT) of the tubing being bent. The simplest design style is the plug mandrel and the most complex design style is the Uni-Flex mandrel. The Uni-Flex ball mandrel is designed to internally support the tube beyond tangent and depending on the number of ball segments, throughout the entire bend.