characterised by their inner surfaces, e.g. having grooves, projections or threads

Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor > Component parts, details or accessories; Auxiliary operations > Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die > Details of extruders > Barrels or cylinders > characterised by their inner surfaces, e.g. having grooves, projections or threads

Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor (extrusion blow-moulding B29C49/04) > Component parts, details or accessories; Auxiliary operations > Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die > Details of extruders > Barrels or cylinders > characterised by their inner surfaces, e.g. having grooves, projections or threads