What is Blow Moulding?

WHAT IS BLOW MOULDING ADVANTAGES DISADVANTAGES Low cost for tools Quick Production Molding of complex parts Produces parts that can be recycled Limited to only making hollow parts Hard to control the thickness of the walls INJECTION BLOW MOULDING This process is used for making glass and plastic products, such as single serving bottles and small medical devices, in high volume. Air in Injection molding prior to blowing Blowing rod Injection unit Blowmoided part 山 [ 01 Ono-way ak valve Injection mold Blow mold (1) (2) (3) (4) The polymer is melted down and then fed into a manifold, which injects it into a hollow mold. This preform mold is what makes the outer shape. The internal shape is formed when the preform is clamped around a core rod, or mandrel. Then compressed air is pumped into the preform, inflating it into its final shape. STRETCH BLOW MOULDING This process is generally used when making bottles, jars, and other containers. Air in Blowing rod Injection unit v, F Blow-molded part Injection mold One-way air valve (1) (3) This process begins with a preform being made as done in the injection method. The preforms are then heated up, usually with infrared heaters. Then it is blown with high pressure air using metal blow molds. The preform is stretched using a core rod. EXTRUSION BLOW MOULDING This process is used for making things like milk and dairy containers, shampoo bottles, and hollow industrial pieces. MILK Extruder barrel Molded part Tube die Mold (closed) Parison Mold (open) Blow pin Air in (1) (2) (3) (4) This process sees plastic melted and extruded into a hollow tube called a parison The parison is then enclosed in a cooled metal mold. Air is then pumped into the parison, causing it to take the desired shape. After a cooling period, the part can then be ejected from the mold. asp PLASTICS Sources: http://en.wikipedia.org/wiki/Blow_molding http://composite.about.com/od/Plas tics/aWhat-Is-Blow-Molding.htm