Material feeding
Depending on the physical form of the material, any recycling line (recoSTAR compact, basic, universal) can be equipped with an edge trim cyclone (for inline operation), reel feeder (for films on rolls), or a feeding conveyor (for loose material, bales, flakes).

Degassing
Regardless of pretreatment, the plastic material is compacted and melted in the single screw extruder. Starlinger’s special screw geometry minimises the loss of quality during this process. Any extruder can be equipped optionally with a vacuum unit or high vacuum unit. The latter is necessary for PET and recommended for moist materials. The vacuum reduces the viscosity degradation and suctions off volatile contaminants and monomers.

Filtration
Solid foreign matter is filtered out by melt filtration. Various types are available: discontinuous (recoSTAR compact), continuous, and continuous filter with backflushing units. The continuous filter consists of a double piston, each piston equipped with a filter unit. In relation to extruder size, each filter unit is large enough to filter 100% of the melt during backflushing or filter change. The main design advantage is a melt flow without corners in which material would otherwise tend to accumulate and become thermally degraded, contaminating the purified melt if dislodged.

Pelletising
Depending on the application, one of three pelletising systems is selected:

• Water ring pelletising
• Strand pelletising
• Underwater pelletising

In conventional strand pelletising, the polymer strands are cooled in a water trough, then cut into cylindrical pellet form.

The advantages of underwater pelletising are ease of start-up, fully automatic operation, manpower savings, space savings, and reduced cooling water requirement.

All three pelletising systems can be equipped with a control system that adjusts the revolution speed of the pelletiser according to the melt pressure in front of the die. This control guarantees even pellet size regardless of output and melt pressure.
All of our pelletising systems supply the same excellent pellet quality, with a maximum surface moisture of 0.1% and flow properties like those of new material.