GROUP MEMBERSMOHAMADEL-SAYEDHASSANM.SOLIMANDJAMAL HISSEINIDIDANESITI HAJARBT SHAMSULKAMARSITI AMINAH BT NORDIN
Blow molding is a molding process in which airpressure is used to inflate soft plastic inside amold cavity.The technology is borrowed from theglass industry with which plasticcompete in the disposable andrecyclable bottle market.Blow molding is a manufacturing process widelyused to create hollow thin-wall plastic objectssuch as bottles, cases, containers, and bellows.
Extrusion blow molding is the oldest,simplest, and most common type of blowmolding.Parison is formed from by forcing the plasticthrough an extrusion die.Material enters the die, flow around themandrel so that extrudate would be cylindrical.The die would have a hole at the center sothat air could be blown into the cylinder.In some blow molding operations, the air isintroduced from the bottom through an inlet.Extrusion Blow Molding
Stretch blow molding is a two-stage process similar tothat of injection blow molding.First, a test-tube like preform is made using injectionmolding or a similar process.The neck of the preforms is fully finished but the diameterand length of the body portion are much smaller than thefinal product.The preform then undergos a stretch-and-blow process.Stretch Blow Molding
Thepolymer isformed bytheinjection ofmoltenresin into amold cavityand arounda core pinThepolymer isnot afinishedproduct, butit issubjectedtosubsequentstep toform thefinal shapeSecond step,blowing oftheintermediate part in asecondmoldBecause ofdistinctseparationof the twosteps, thepolymermade byinjectionmolding iscalled apreformInjectionBlowMolding
Place the blow stem in an injection moldInject melted thermoplastic material into themold to create the preform around the blowstemPlace both the preform and the blow stem into a twopiece molding chamber and inject compressed airthrough the blow stem into the preformThe molded plastic will be left to cool and harden.Once released from the mold, the plastic part can bepost-processed to have the holes rimmed or residuestrimmed.Bottle Making Process
Many types of materials to choose fromQuick product revisions for increased flexibilityTooling is less expensive than Injection MoldingEach part price is less than Rotational Molding (fastercycle)One piece construction (no need to connect part halves)Excellent ESCR (environmental stress crack resistance)
Environmental DisadvantagesDependence on PetroleumProcess and Material LimitationsAssorted Accumulation Methods