An open and shut case for automated fabrication

Working with machine manufacturer SOGA Gallenbach on a project for blinds manufacturer ROMA, STOBER supplied the automation technology that includes planetary gear units, rack and pinion drives and drive controllers for its LeanMotor driven multiple head manufacturing system. Prior to the design of the new fabrication system, ROMA had drilled and screwed between two and three aluminium (or plastic) profile rails using an unmonitored screw-fed unit. However, too 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 explains: “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 up to 5.7 metres. A further requirement was that the new system needed to be sensitive to the torque properties of plastic 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 equipped with five mounting heads that move independently of each other in the X direction on a gear rack. Each head is 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 and software limit switches that were parameterised with the permitted travel range for each X-axis. A mechanical safety switch was also located on each head. The lightest possible compact motor was installed for the drilling spindle, which permitted rapid positioning for the five axes.

In addition to drilling, countersinking was made possible by the integration of STOBER’s encoder-less LeanMotor (LM), which the company says is significantly lighter and more compact than an asynchronous motor. With the same output, it is also claimed to be more cost-efficient and durable 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 which are located as closely as possible and attain  energy efficiency class IE5 with up to 96 percent efficiency, providing the added benefits of lower energy consumption and long service life. As a result of the installation ROMA is now said to be operating with significantly more process reliability and has also removed a frequent need for costly reworking.