Mr. Martin Rothmann from the WITTE Stromberg GmbH knows very well that weld spatters in the large scale production are a significant cost factor. Why that’s no longer a problem for him – more on this later. Martin Rothmann is the Head of Production and Logistics of a company which has since 1899 a consistent business development.
The company, founded by Ewald Witte, had begun to manufacture case fittings before it started soon to produce car fittings. The VW beetle was the first car which drove with a Witte-door handle through the world. In the 1950s the production of goods for the automobile industry has been strengthened by the own casting production and they expanded to the European market. In the 1970s the production program has been revalued due to own development activities for all components of locking and latching systems. By the establishment of subsidiaries and company acquisitions the WITTE Automotive group was formed with a wide range of competence and technology spectrum.
Nowadays the Witte Stromberg GmbH is developing and producing, in corporation with many renowned automobile manufacturers, locking systems for front and rear hoods, locking systems for vehicle doors and safety products for vehicle seats and has currently about 150 employees.
Panasonic delivered the first robot cell already 2002 to the company in Stromberg. Although 10 years of productive use are left behind since the installation of the robot, the system is running without complaint. But since this installation lots of changes relating to the welding technology has been done. Panasonic is supplying for more than 50 years all components in the field of MIG/MAG and TIG welding all from one. Since 2005 Panasonic has integrated the welding power source in the robot controller (TAWERS = The Arc Welding Robotic Solution) and developed innovative types of arc-welding.
The use of leading-edge welding technology is of course necessary to supply the customers of Witte Stromberg with high quality products. Therefore the client-base includes mainly automotive manufactures from the quality and premium segment. One of the last installations is the PerformArc-Table/table cell with “TAWERS Active Wire” technology. The Panasonic “Active Wire” technology is a combination of regulated short arc with digital short resolution and a synchronized pulsing wire feed. With “Active Wire” it is now possible to achieve high quality and visually pleasing welding results in series production by a minimum of cycle time. It also works in out-of-position welding.
The welded motor vehicle hinge parts are in the visible range and therefore are not allowed to have any spatter. Mr. Rothmann emphasizes that no reworks have to be done anymore: „Spatter are no longer an issue. In the past we had to do 100% final visual inspection.” Until now rework was necessary by more than 25% of the welded work pieces!
At the „Active Wire” system it is noteworthy that the usual wire feed on the third axis is eliminated. The integrated “Active Wire” wire feed in the torch head has minimal moving mass and can therefore work highly dynamic. The wire feed will be supported by the Panasonic Wire Booster which is directly installed on the wire drum.
The space of the wire in the wire guide serves as a wire buffer, whereby the „Active Wire“ system can completely renounce an expensive and susceptible wire buffer unit. Due to the excellent results further production cells have been equipped with the “TAWERS Active Wire“ systems. In addition to the elimination of rework, the reduction of cycle time could also be achieved, since the exceptional gap bridging of the “Active Wire” process allows faster welding.
In a further Panasonic welding system soft top components are welded as well. Here the benefit of easy programming of Panasonic robots made it much simpler for the user. Although the work piece geometry and the clamping tool normally requires a laborious programming work, was the preparing of programs with the teach panel an easy task.
Nowadays a total number of 16 Panasonic welding robots are used. Mr. Rothmann, who is in charge of production, is “very satisfied with Panasonic”, and also the employees are very pleased with the “trouble-free operation” in the production. Even the system fitters and operators are convinced of Panasonic robots as they are from their experience very user-friendly and easy to program. Regarding safety at work Panasonic and Witte Stromberg presenting themselves also exemplary. So far no accident happened in the production with Panasonic robot systems.
In the meantime Witte Stromberg using Panasonic products more than 10 years and could consistently collect positive experiences during this time. Especially the reduction of cycle time, the easy programming of robots and the trouble-free operations in the production form the basis for a further successful corporation with Panasonic.
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