Compact drive and control technology in a cosmetics filling plant

When retrofitting a tufting machine for carpet production, Vetex, a German company, replaced all of the control and drive technology. Over 400 compact stepper motor drives are used for the yarn feed.

Herzebrock-based carpet specialist Vetex offers carpets in a wide variety of patterns, colors, and dimensions. The most commonly used process for carpets worldwide is tufting, a technique between sewing and embroidery. Needles threaded with the pile yarn (tufting yarn) pierce the backing material, which is moved synchronously to the machine cycle by a feed roller and a take-off roller. The vertical needles are arranged across the entire width of the tufting machine – in the case of the Vetex machine, exactly 1,696 needles across a width of 4.29 meters. “That corresponds to ten needles per inch of carpet width,” explains Ralf Bosch, production manager for the Vetex tufting and weaving division. 

When the electronics started to fail more and more often, Vetex – based in Herzebrock – realized it was time to retrofit one of its tufting machines and migrate to PC-based control.

During the retrofit of the tufting machine, the previous drive technology was replaced with various AM8000 synchronous servomotors and AX5000 compact servo drives, which control aspects such as the needle stroke, the feed of the tufting fabric, the press foot, and the lifting table. “For the most important part of the retrofit – the precise yarn feed and thread tension – Vetex relies on a new concept that could only be implemented in this form with the compact integrated ASI8114 stepper motor drives,” explains Jens Hülsebusch, project manager and programmer of the retrofit at Beckhoff. A total of 424 stepper motors with integrated amplifiers each pull four threads from the creel via corresponding shafts and make them available to the machine via scramble box and puller rolls. The speeds of the yarn drives can change up to ten times per second.

“Due to their compact dimensions, the flange dimension of 42 mm, and the low power consumption, the stepper motor drives could be mounted very closely,” adds Christian Mische, Senior Product Manager Drive Technology at Beckhoff. “Compared to other solutions, the design effort required for the infeed of the 1,696 individual yarns is therefore much lower and more precise,” confirms Ralf Bosch.

The thread tension is displayed synchronously to the cycle via the torque of the stepper motor drives in the visualization created with TwinCAT 3 PLC HMI; each dot in the matrix above the thread infeed represents one of the 424 stepper motor drives.

The thread tension is displayed synchronously to the cycle via the torque of the stepper motor drives in the visualization created with TwinCAT 3 PLC HMI; each dot in the matrix above the thread infeed represents one of the 424 stepper motor drives.

The compact drive technology with 48 V DC supply voltage saves valuable installation space – but that’s not all. Its internal feedback system turns the stepper motors into a precise servo drive with field-oriented control. To find out what this means in comparison to conventional stepper motors, you can read the detailed application report:

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