Georg Sahm GmbH & Co. KG, based in the German town of Eschwege, is a technology leader in the automatic winding of all kinds of technical yarns. Its portfolio includes automatic and manual precision winding machines, automatic bobbin removal devices and transport systems. For extremely precise winding of the high-performance fibres and technical yarns, SAHM uses the TWINSTAR II automatic precision cross winder. The stringent quality requirements of its customers demand high-quality technologies such as Controlled Pneumatics and standard pneumatics from Festo.
When winding yarns, such as high-performance fibres, multifilaments, coated and twined yarns, they need to have uniform, continuous lengths and higher spool weights so they can be processed economically, but they then become too heavy for the operator to remove. Parameters such as tensile force, winding speed or winding precision decide whether a technical yarn can be turned into a flawless high-tech product. What was needed was a solution that combines high control accuracy during winding with a flexible and very reliable solution for changing the bobbins. The high-performance yarns are then used to make high-quality products for safety-related areas, such as fire and safety clothing, helmets or automotive applications.
The TWINSTAR II winder meets these requirements very reliable, thanks in part to Controlled Pneumatics from Festo. The proportional pressure regulator VEAB controls the yarn tension very precisely and dynamically. When controlling the contact pressure on the bobbin, high accuracy and linearity are key factors. Both ensure the bobbin winding result is more precise, even at a maximum winding speed of up to 2500 metres per minute.
The piezo technology used in the proportional pressure regulator VEAB requires very little electricity to operate compared to conventional solenoid valves. The piezo elements maintain the tension without generating any heat. The VEAB, together with the precisely configured control algorithm, responds quickly and highly accurately, using the exact amount of compressed air required to control the process.
The fully pre-assembled and tested module also uses standard pneumatics in the form of valves VTUG. As part of the compact and high-performance unit, they ensure that the automated bobbin change is fast and reliable, without wasting any material and without any downtime. The standardisation of these systems enables them to be scaled to multiple TWINSTAR II variants.
Innovations are part of the DNA of SAHM. That is why the company is always on the lookout for partners that are also drivers of innovation, explains Martin Schmidt, Head of Purchasing: "Festo supported us very well with its product range, but also with its process knowledge, and helped us solve the problem very quickly and efficiently. Controlled Pneumatics sets new standards that will enable us to significantly strengthen our market position in the medium and long term. That's why we use this technology."