With small screws the size of the granules has a significant influence on the plastification process. The demand for higher plastification rates caused by the use of multi-cavity moulds can be fulfilled by adaptation of the screw geometry by consideration the conveying and melting mechanisms. For screws with small LID-ratio it is difficult to find a general purpose screw. Especially the processing of polyamide with flame retardants can cause process inconsistency The Doublemelt plastification system is optimised for such plastics with a narrow processing window.