FIT FOR FREE-FORMING

In the past, free-form tubes were in demand primarily from the furniture business for design reasons. These days, however, demand is generated from all industrial areas. Consequently, more tube benders need the right measuring systems which take the particularities of complex free-form tubing into account. This is where the optical measurement system TubeInspect from Aicon 3D Systems GmbH (Braunschweig, Germany) offers an ideal solution.

This system carries out very precise testing of free-form tube geometries with the help of high-resolution digital cameras, then goes one step further: it uses an additional interface to connect directly with the free-form bending machine. This interface enables the system to identify the automatic correction values for the formed tubes and transmit those values to the bending machine. Setup time is shortened considerably.

This direct interface is made possible through a close cooperation between Aicon and bending machine manufacturer Wafios AG (Reutlingen, Germany). Peter Seidel, sales manager of the Tube Business Unit at Wafios AG, explains how this cooperation came about. "It's really important to us that users not only get the most innovative bending technology, but parallel to this, get reliable testing methods to carry out their quality assurance,? he says. ?That's why when Aicon approached us about working together, we immediately agreed to being a development partner for a direct interface between free-form bending machines and TubeInspect ? even though this means giving them very intimate insight into our own bending technology and software."

Aicon is a leading manufacturer of optical camera-based 3D measurement systems. Founded in 1990, the company was a spin-off of the Braunschweig Technical University and the VW Group's R&D unit during a time when shareholders Dr.-Ing. Carl-Thomas Schneider and Dr.-Ing. Werner Bösemann were already working in the field of camera-based optical measurement technology. Now the company has 45 employees and supplies automotive manufacturers and their suppliers, as well as manufacturers in the aerospace industry, shipbuilding and renewable energies.

Wafios is a global manufacturer of wire and tube processing machines and cold forming presses. It exports approximately 65 percent of its diversified machinery to individual markets, suppliers and customers in 71 countries.

But why is correction on free-form bending machines so complicated? In contrast to tubes manufactured conventionally by draw bending, which consists of calculated lines and bends and feature constant radii, free-form tubes manufactured by push bending have a completely different set of parameters.

In a CAD system they are often shown as a spline, a tube geometry in which, theoretically, a different radius can exist at any point. When correction takes place on a conventional bending machine, only the LRA values at the individual bending points must be corrected. In comparison to this, to achieve the desired tube geometry using free-form bending, a multitude of different settings on the bending machine must be adjusted and the bend radii optimized until the exact tube form has been bent.

This type of setup has ? to date ? been an unbelievably time-consuming process with high material usage, so that both automation and shortening of the process were the two main objectives. Now this optical measurement system masters the challenge with a direct interface that enables smooth communication between the bending machine and the measurement system.

For example, the demand for free-form bent tubes has increased dramatically throughout various markets, especially in the automotive industry. Bösemann, the managing director of Aicon 3D Systems GmbH, explains the reasons why. "Design demands or technical necessities call for tube forms, which often can no longer be manufactured on conventional machines,? he says. ?Maximizing efficiency, however, is another reason why many companies are migrating from conventional bending processes to free-form bending. One of our customers is currently testing the possibility of manufacturing its brake lines using push bending, a form of free-form bending. Their calculations show that employing this method would achieve significant cost-reduction, as the bending time per tube is lower."

The manufacturer, which already has a TubeInspect system, can ? thanks to the newly developed interface ? connect their measuring machine directly to the Wafios B10 or BMZ series tube bending machine and, in doing so, considerably reduce set-up and cycle time.

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For more information, contact Andreas Hoster at Wafios AG, Silberburgstrasse 5, D-72764 Reutlingen, Germany, +49 (0) 71 21 ? 146 309, Fax: +49 (0) 71 21 ? 49 12 09, or email him at [email protected].

For more information, contact Jutta Thiel at Aicon 3D Systems GmbH, Biberweg 30C, D-38114 Braunschweig, Germany, +49 (0)531 ? 58 000 70, Fax: +49 (0)531 ? 58 000 60, or email her at [email protected].