The increased feed speed is generated using compressed air. WEBER has therefore adapted the feeding system to withstand higher material loads. A key priority in the feeding process is the gentle handling of the screw, especially protecting the screw tip from damage.
The higher feed speed must be significantly reduced just before the junction between the feed hose and the screwdriving spindle. To achieve this, WEBER uses a patented high-speed brake (BR-H), designed as a simple helix (circular loop). Even in this newly developed helix, the screw is transported and fed with maximum care and minimal abrasion.
For WEBER customers, this new high-speed brake offers a significant cost advantage compared to expensive and failure-prone magazine solutions that other manufacturers use to reduce feeding times. Cycle times for successive screwdriving operations can be shortened by up to 1.3 seconds; previously, the screwdriver occasionally had to wait for the next screw—now, feeding and screwdriving processes flow seamlessly into one another. Another advantage is that all WEBER systems are retrofittable. The helix brake and the required reinforced hose connectors can be added to all existing screwdriving systems at a later stage.
„Robot pushing“ minimized
During flow-drilling screwdriving operations, forces act on the screwdriving spindle and the screw itself, consisting of required process forces and unwanted lateral forces. When robots are used, these lateral forces can cause the robot to shift by up to several millimeters due to leverage effects and/or joint play. This so-called “robot pushing” can lead to the screw tilting or breaking.
In addition, automotive manufacturers using the RSF25 for flow-drilling screwdriving are increasingly relying on high-strength steels to meet safety and strength requirements, which require high joining forces.
WEBER offers two cost-effective solutions for these screwdriving cases that significantly increase process reliability.
The first solution approach lies in the software-based exchange of force development data at the screwdriver. Specifically when using robots from KUKA, WEBER sets up an additional signal exchange via the software interface. This allows real-time data on the forces currently acting between the screwdriving spindle and the robot to be exchanged. This ensures that the robot applies a compensating force at the moment of highest force during the screwdriving process. This makes it possible to reduce lateral forces by more than 50 percent.
A second solution presented by WEBER is independent of the robot manufacturer. A mechanical compensation module is used at the screwdriver that triggers a lateral translational movement of the screwdriver and counteracts the lateral force. This also reduces these unwanted lateral forces by 50 to 60 percent.
Significant customer benefits
Both the high-speed brake and the two solutions for reducing “robot pushing” offer significant advantages to WEBER customers. Each of these RSF25 innovations results in a substantial increase in process reliability. In addition, the use of the helix brake enables a massive reduction in cycle times, while the compensation of “robot pushing” through data exchange or a compensation module allows for the screwdriving of high-strength materials. All components can be retrofitted with relatively little effort and represent a cost-effective option for executing assembly processes—and especially flow-drilling screwdriving—more efficiently and with the required quality. The system components are available on the market immediately and can be ordered.
