Eliminating tube waste

Paul Boughton
High quality materials have found their way into all areas of automotive production. Tubes are no exception here: manifold tubes in the engine compartment, axle components or tube components in the exhaust system are manufactured from cost intensive primary materials in huge quantities. To allow any bending of the frequently very short components, the parts to be bent are generally artificially extended with span and supporting lengths. After bending, the additional lengths must be separated again from the bent part in separate operations and they accumulate as waste.

“This practice drives up the manufacturing costs for a component. We have therefore produced a solution, which not only reduces the required material quantity; it also shortens the production time,” explains Schwarze-Robitec Managing Director Bert Zorn.

Here, the approach of the bending specialist from Cologne is as obvious as it is effective: a separator has been integrated into the new bending tool. Significantly longer tube rods – even entire commercial lengths – are now used to bend the components.

After bending the first part, the separator is used to separate the finished component from the straight remainder. The remaining, straight part of the tube is transported further into the bending machine, bent anew, then cut off again using the integrated device.

In each case, only a narrow shaving is created here, which is cleanly taken away. As such, the entire material is processed very quickly and highly efficiently into finished tube components.

“Only at the front and rear ends of the tube does waste occur that cannot be used, which is conveyed out of the machine,” adds Hartmut Stöhr, who is also a Managing Director at Schwarze-Robitec. “Overall with the integrated system, up to 90 percent of the tube waste incurred with other production solutions can be avoided.”

Whereas up to 100 millimetres of waste has previously been accrued per tube in the production of manifold tubes depending on the bending system, this cost driver falls to only one tenth with the Schwarze-Robitec solution, eg if ten tubes are coupled and separated directly in the machine – a great cost advantage. Additionally, users can omit an external separator here, which reduces operating costs in the form of depreciation. At the same time, the companies benefit from a noticeable increase in productivity due to reduced cycle times per component.

The innovation has been developed for the fully electric CNC 100 E TB MR and CNC 80 E TB MR tube bending machines from Schwarze-Robitec. However, in future, it will be possible to integrate it into almost any bending tool.
Indeed, the CNC 100 E TB MR in particular is used for large-volume production processes with short tubes, which is when the bending and separating solution optimally displays its cost advantages.

Another plus for the user is the great flexibility of the CNC tube bending machine: tube components diameters between 25 and 114.3 millimetres can be processed. Here, it is equipped with a loosely mounted bend former and with the tried and tested Schwarze-Robitec replenishment and multi-radius technology, which allow automated bending on several levels. Moreover, it has a bending tool for mandrel bending with integrated bend-in-bend clamp jaws and a tube separator. Even tight radii and short intermediate lengths can therefore be produced on one tube in only one process.


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