Taking control of the automated fabrication process


Drive engineering specialist, STOBER, explains how it helped create a new multiple screwing unit that joins profile rails, monitors screw depth and tightening torque for ROMA, the international manufacturer of roller shutters, venetian blinds and textile screens. 

Working with machine manufacturer SOGA Gallenbach, STOBER supplied automation technology that includes planetary gear units, rack and pinion drives and drive controllers for the LeanMotor driven multiple head manufacturing system.

Prior to the new fabrication system design, ROMA drilled and screwed up to three aluminium or plastic profile rails using an unmonitored screw-fed unit. Frequently, the drill screw created chips between the screw head and the profile rail, meaning that the system had to be reworked manually.

STOBER’s Martin Preece explained: “ROMA’s brief to the design team was for a system that, as well as eliminating the need for manual intervention and reworking, enabled them to process pre-drilled profile rails in lengths from 710mm to 5.7Mtrs. A further requirement was that the new system needed to be sensitive to plastic’s torque properties in the final tightening process. The design was also to be equipped with two drawers for loading the profile rails for processing, either separately or synchronously.”

The new drive solution now feeds the profile rail screws automatically and inserts them pneumatically.

It also includes one PE series planetary gear with a belt and ballscrew drive combined with an EZ synchronous servo motor for each drawer, enabling them to move automatically using two Y-axes.

The unit is also equipped with five mounting heads that move independently of each other in the X direction on a gear rack. Each head was equipped with a Z-axis and drilling axis, as well as providing ZV_PE series rack and pinion drives with EZ synchronous servo motors for the X-axis. EZ-motors with ballscrew drive are also used for the Z-axis.

To ensure that the five heads do not collide with each other on the gear rack, STOBER engineers implemented threefold collision protection that included controller monitoring of the positions in relation to each other; software limit switches that were parameterised with the permitted travel range for each X-axis; and a mechanical safety switch located on each head.

The lightest possible compact motor was installed for the drilling spindle, which allowed rapid positioning for the five axes.

In addition to drilling, countersinking was made possible by integrating STOBER’s encoderless LeanMotor (LM), which is significantly lighter and more compact than an Asynchronous motor. With the same output, it is more cost-efficient and more rugged than a servo drive and uses a single, standard power cable.

This made it possible for ROMA to set speed and torque to any point, from standstill to maximum speed, with full torque control.

Each head has three motors located as closely as possible and reach the energy efficiency class IE5 with up to 96% efficiency, which gives the added benefits of lower energy consumption and long service life.

“STOBER combined the motors with new double-axis controllers from their SI6 series. This highly dynamic solution also makes challenging movements possible, with enhanced safety aspects provided through the integration of STO (Safe Torque Off) and SS1 (Safe Stop 1) safety functions, certified in accordance with EN 13849-1 (PL e, cat. 4),” added Martin.

The result for ROMA is that it now operates with significantly more process reliability and has removed the need for costly reworking.





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