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Step 1. Injection
The injection blow moulding machine is based on an extruder
barrel and screw assembly which melts the polymer. The molten
polymer is fed into a manifold where it is injected through
nozzles into a hollow, heated preform mould. The preform mould
forms the external shape and is clamped around a mandrel (the
core rod) which forms the internal shape of the preform. The
preform consists of a fully formed bottle/jar neck with a thick
tube of polymer attached, which will form the body.Step 2. Blowing
The preform mould opens and the core rod is rotated and clamped
into the hollow, chilled blow mould. The core rod opens and
allows compressed air into the preform, which inflates it to the
finished article shape.
Step 3. Ejection
After a cooling period the blow mould opens and the core rod is
rotated to the ejection position. The finished article is
stripped off the core rod and leak-tested prior to packing. The
preform and blow mould can have many cavities, typically three
to sixteen depending on the article size and the required
output. There are three sets of core rods, which allow
concurrent preform injection, blow moulding and ejection.
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Molding
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