Weaving without harness - Lubrication-free plastic bearings in innovative weaving machine

Permanent movements in 24/7 operation. The machines should have as much downtime as possible, because every standstill is associated with a lot of repair and maintenance work and costs.

With the iglidur® J3 material, a significant improvement in service life was achieved. The freedom from maintenance and lubrication ensures that no dust or dirt from the environment is bound to the bearing points.

It was not until the 1980s that the punched card technology of the looms was replaced by electronic control systems. The basic mechanical principle has lasted even longer. The individual warp threads are moved by the so-called "harness system": this is a mechanical connection that raises or lowers each heald according to the desired pattern using hooks and pulleys or return springs. The individual harnesses are usually operated by magnets.

There is now a much more flexible alternative to this very complex principle. Gitec GmbH in Neu-Ulm has developed the UniShed 2, the world's first harnessless jacquard weaving machine. Each warp thread is individually controlled by a piezo actuator. A mechanical oscillation system replaces the traditional harness system with hooks and return springs.

One of the design challenges that had to be overcome when building the first prototype machines was the bearing support for the oscillating shafts, which have a diameter of 50 millimetres and are moved by servomotors via an electronic cardan drive. Roland Michel: "These bearings are subject to heavy loads, as the shafts oscillate and the systems work as endurance runners in 24/7 operation. At the same time, they have to manage without external lubrication because the mesh is generated underneath the shafts. We initially used plain bearings from another manufacturer, which ran technically flawlessly but were quite expensive. As the textile industry is very price-sensitive and each individual axis is stored many times, we switched to igus® bearings."

Originally, the standard material iglidur® J was planned, which as a genuine endurance runner material is very wear-resistant and has low moisture absorption. But according to the motto "the better is the enemy of the good", igus® developed the new material iglidur® J3, which is characterised by even better wear resistance. Depending on the application conditions, up to three times longer downtime is achieved compared to iglidur® J.

The machine, which is currently working in the technical centre in Neu-Ulm, is equipped with eleven modules, each with 128 piezo actuators. As each module is supported by two bearing bushes, there are 22 iglidur® J3 bushes with a diameter of 50 millimetres on each axis.

With the UniShed2 machines, Gitec is targeting the classic applications of Jacquard weaving machines such as clothing, home textiles and - in particular - technical fabrics made of polyester and polyamide as well as glass-fibre reinforced plastic/CFRP materials. New methods of airbag production are currently being tested in Neu-Ulm. Roland Michel: "Until now, the airbag bags have been sewn together from two parts that were previously cut to size and coated. With the UniShed2, we are now trialling the weaving of hollow bags from a single piece. This significantly simplifies the process."

As a subsidiary of a Chinese group that specialises in the textile production process chain, Gitec GmbH, which emerged from the long-established textile machinery manufacturer Grosse, also has direct access to the practice of industrial weaving: the parent company operates its own weaving mills near Shanghai, which produce sophisticated jacquard fabrics for technical applications.