It has long been an ambition of automobile manufacturers to produce bodies in white for different models in short cycle times and with as little conversion work as possible on the manufacturing equipment. Nothelfer GmbH has now developed solutions which bring the goal of a flexible body shop a good deal closer.

The geometry cell, in which the side panels, floor assemblies and roof cross members are welded together, plays a key role in determining the quality of an automobile. The fact that different side panels have to be supplied for different variants such as four-door, two-door or station wagon models represents a problem, however. The solution practiced to date involves moving the supporting and clamping frames for the parts backwards and forwards at the side of the production line. Another common solution is to have an additional geometry cell for different model variants. However, both processes involve interruptions to the production sequence, leading to unproductive downtime and taking up additional space.

Nothelfer?s response to this is the "body framing" concept, which uses a gantry to gate the clamping frames in and out of the production process. These clamping frames are loaded with the various side panels manually or automatically. The gantry picks up the frame from a zone behind the welding robots and is so quick that three different variants can be positioned within a cycle time of 60 seconds. Another advantage of the new solution is that there is more room for welding. This contrasts with conventional production concepts in which one side of the geometry cell was always blocked by the required clamping frame. The body framing process is suitable for making prototypes, very small batches and also for high volume production. Nothelfer has submitted the process for patent and several units have already been sold.

"Integrated body framing" is the name of a method developed by Nothelfer for assembling side panels with a flexible approach to models and variants. It involves a lifting system collecting the required clamping frame from a rotating buffer formed by a telpherage. The components for the side panels are inserted into the clamping frame and firmly clamped. Once the welding robots have positioned the geometry welding points, the parts move onto a working station involving stud welding, adhesive application and quality control. A cross-slide then brings the side panels to the geometry cell where they are clamped to the floor assembly and welded. This application is also patent pending and is already in practical use with several customers.

Of course, flexibility in connection with the clamping frame demands a high degree of freedom in the clamping levers. To this end, Nothelfer has developed a system abbreviated in German to "KIPES" which features compact installation for the pneumatic/electrical clamping unit. In conventional clamping frames with 20 to 25 pneumatically operated clamping levers, for example, the levers can only be operated in groups of four or five with one valve per group. As a result, changes to the shape of the component give rise to great complications during installation. Frequently, the entire pneumatic unit has to be reconfigured. KIPES enables the clamps to be individually controlled. Each toggle clamp has an independent valve. This makes it possible to adapt the configuration of the clamps quickly to the particular shape of the component. A further innovation is that the clamps can be controlled from a PC.

A patent application has been submitted for KIPES and also for a novel lifting and rotating unit which enables the complete floor assemblies or entire bodies to be turned. Compared to conventional drum turning fixtures, this unit offers the advantage that it can be loaded from all sides. Furthermore, it can be installed level with the floor and can therefore be accessed without any risk of tripping. Nothelfer has already received several orders for this innovation too.