SF&DS has therefore developed a blowmoulding machine in which all the layers are fabricated at the same time. Instead of using just one extruder on the blowmoulding machine, several extruders are used for the different types of material that make up the bottles. The different products come together in an extrusion head and are shaped around one another into a three or six-layer tube of molten plastic. Inside the blowmoulding machine the hollow tube, which is still hot, is cut into small pieces (called parisons) and loaded into moulds on a carrousel. Sterile air is then blown into the pieces of hollow tube, which are inflated and take up the shape of the mould, i.e. the shape of the bottle. After the carrousel forming process, the bottle is removed from the carrousel and another parison is loaded into the mould. In this way, a SF&DS blowmoulding machine can produce 6,000 one-litre multi-layer bottles per hour.
Producing multi-layer bottles – how does it work?