Compounding: Twin Screw in a New Size

Coperion has expanded its STS twin-screw series by one more size: The new STS 25 Mc¹¹ extruder features a 25-mm screw; it’s built for R&D and and is designed especially for research and development as well as for production of small batch sizes up to about 200 lb/hr. The machine debuted during last month’s Chinaplas 2019 in Guangzhou, China.

Like other machines in the STS series, this 25-mm twin is designed simply and is said to be operator-friendly and easy to clean. Its feed barrel is equipped with an exchangeable sleeve insert to facilitate cleaning. In addition, the die head features a quick-release design for easy operation and faster product changeovers. The base frame has a closed, simple-to-clean surface, and is equipped with castors for easy movement of the extruder and fast installation. Water cooling, vacuum unit and air supply can be integrated into the base frame as an option.

Coperion has equipped the new STS 25 Mc¹¹ extruder with cartridge heaters for precise single zone tempering of each individual barrel. The entire STS series has the same screw diameter ratio (D_o/D_i : outer screw diameter to inner screw diameter) of 1.55 and the same maximum specific torque Md/a³ of 11.3 Nm/cm³. That way, production parameters of the STS 25 Mc¹¹ can be reliably scaled up to larger STS sizes. The STS 25 Mc¹¹ Coperion exhibited at featured a Coperion K-Tron twin-screw feeder K-ML-SFS-KT20.