Ellapack Blow Moulders of Plastic Bottles Containers and Technical Parts

The Process

Air is blown into a thin walled plastic cylinder called the parison. The parison is formed by melted plastic material being pushed through an extruder.

When the parison reaches a certain length, the two halves of the mould close around the parison sealing it at the bottom. Compressed air is then used to inflate the parison to form the shape of the cavity inside the mould.

The plastic begins to cool and become firm, the mould opens, and the new container is removed.

Typical Moulding Process

Blow Moulding Dictionary

	Flash	Extra plastics attached to a moulding along the parting line. It must be removed before the product is considered finished.
	Blow Rate	The speed at which the air enters the parison during the blow moulding cycle
	Cycle Time	The period between a certain point in one cycle and the same point in the next
	Recycle	Ground materials from flash and trimmings which, after mixing with a certain amount of virgin material, are fed back into the blow moulding machine
	Parison	The hollow plastics tube from which the product is blow moulded
	Deflashing	Covers the range of finishing techniques used to remove the flash (excess unwanted material) on a plastics moulding
	Flash Line	A raised line appearing on the surface of a moulding and formed at the junction of the mould faces
	Mould Seam	A vertical line formed at the point of contact of the mould halves
	Lip	The outer edge of the top of a container, intended to facilitate pouring
	Cavity	Depression in a mould that forms the shape of the product to be moulded
	Blow Pressure	The air pressure used to form a hollow part by blow moulding
	Extrusion	The compacting of plastics material and the forcing of it through an orifice in a continuous manner
	Cross Head	A channel which changes the direction of the ‘melt’ from a horizontal flow through the extruder, to a vertical flow through an extrusion die to form the parison