A blow moulding process

Raw materials are delivered from supply hoppers (10, 11, 13) to a blender (12) which feeds an extruder (14). A tubular plastics parison is extruded downwardly from an accumulator head of the extruder (14) over a pair of blow pins to which it is clamped. A pair of mould halves of a split mould (16) are closed about the parison in a number of steps, incrementally reducing the mould closing speed for each successive closing step. Pressurised air is injected into the parison to inflate the parison against an inner wall of the mould (16) to form a drum. The mould (16) is then opened and the drum is discharged from the mould (16). Preferably, downstream of the mould (16), the drum is cooled in a cooler (50) by supporting the drum between cooling plates which engage a top and a bottom of the drum. Cooling water is circulate through the cooling plates for a desired cooling period. The drum is also sealed and cooling air is circulated through an interior of the drum while maintaining a preset desirable air pressure within the drum .