1.3 Continuous Extrusion Blowmoulding

There are several different methods for blowmoulding and all of them are based on the over-simplified concept shown earlier. Since it would be impossible to review all of the different types of machinery and processes in this one presentation – we will closely examine just one method, ‘Continuous Extrusion Blowmoulding’.

Continuous extrusion blowmoulding is the process normally selected to make large quantities of precision parts that must work in close tolerance with other parts, such as caps. Also, continuous extrusion is suited for processing several different kinds of plastic.

Examples of containers that are made through the continuous extrusion method of blowmoulding are shampoo, mouthwash, and cooking oil bottles. To produce any blowmoulded item there are four essentials. The extruder, which is a machine that prepares plastic into parison form. A clamp section, a unit which holds and moves moulds and blows the parison. Support systems supply electricity, resin, compresses air, and chilled water to the machine. The manufacturing staff, the groups and individuals that run the blowmoulding process on a production basis.

Figure 7: Example of Containers