TPT January 2014

Technology News

Tube bending tooling BEND Tooling Inc of Michigan, USA, has supplied companies around the world with tube-bending tooling since 1986. It produces die sets, mandrels, and wipers for rotary-draw tube- bending machines for most makes and models. Bend Tooling is also distinctive as the developer of the modern inserted mandrel and wiper. Its inserted designs are favoured by production tube-bending operations in the automotive, sports vehicle, HVAC and hydroforming industries.

companies benefit from the lower per- bend cost, the consistent reliability, and the easier stocking and JIT shipping of Bend Tooling’s inserted mandrel and wiper in place of traditional solid-body ones. Bend Tooling also manufactures high-quality solid-body mandrels and wipers for those tube-bending jobs that need them. This primarily includes bending under extreme high pressures and bending non-round tube. Bend Tooling Inc – USA Email: sparrow@bendtooling.com Website: www.bendtooling.com

They are also widely used by speciality tube-bending companies because of their consistency in specification, which facilitates frequent changes in set-up. All tube-bending

Bend Tooling is distinguished by precision machining every feature of its tooling. This eliminates hand- working and improves quality, shortens lead times, and reduces costs.

Straight and pre-stressed tubes THE tube and pipe industries utilise straighteners, both in-line and off-line, with regard to the main manufacturing process. Straightening products involves ‘stressing’ the tube in a particular plane (or planes) to counteract forming, internal material or welding heat stresses, all of which can be removed or balanced by using straighteners. roll or multi-plane straighteners tend to be used to counteract forces within a tube or pipe that are variable and multi-directional as the product moves through the straightener. These units have been recently used in applications where manufacturers want to “raise the level of work hardening” within their product without adding heat treatment processes or speciality materials.

Turkshead straighteners involve an operator to adjust the unit to counteract the internal stresses, but as these stresses change, the turkshead must also be changed. This is not entirely true with a multi-roll or multi-plane straightener, which is more robust to small changes as it stresses the tube multiple times to achieve straightness. More rolls can be added to achieve a state that almost does not require an operator for all but the most stubborn material characteristics. Straighteners can be used before special forming units or after them, depending on the specific manufacturing method.

Since these straightening devices work by imparting stresses to counteract already-present stresses, they are a viable choice to add percentage points to the work hardness of a product without imposing other damage, such as ovality changes. Too much straightening can damage the OD characteristics of a tube or pipe, so there are side effects that must be monitored in order to achieve the highest level of quality within a process.

Many types of straightener are used in the manufacturing environment, including multi-roll or multi-plane, turkshead and cross-roll. Cross-roll straighteners tend to be used as an off-line processing action, as the tube or pipe is typically cut to a finite length, rolling radially as it is processed. Turkshead straighteners are used in- line in tube and pipe mills, and use either two- or four-roll designs to encompass the tube and impart a force (or stress) in up to two axes of direction. Multi-

Formtek, Inc – USA Fax: +1 216 292 2898 Website: www.formtekgroup.com

Multi-roll straightener or stressing unit (prior to wire forming)

Multi-roll straightener or stressing unit (post wire forming)

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J anuary 2014