Blow molding is used to manufacture hollow plastic products.
Plastic for the injection moulding comes in the form of plastic granules. These plastic granules are first melted down and extruded through a hollow sphere or tube with a hole in the one end, which is then inserted into a mould. Air is blown to inflate the plastic to the correct shape.
- Injection blow moulding
- Spin trimming
- Injection stretch blow moulding
- Extrusion blow moulding
Injection blow moulding is used to mass produce plastic products, using molten polymer which gets fed into a hot runner manifold leading to a heated cavity and core pin. This type of blow moulding is an accurate form for the mould. with injection blow moulding, smaller quantities of the product can be produced
Injection stretch blow molding can produce high volumes of plastic products. But is also suitable for smaller volumes of the product and short runs.
Spin trimming is used to trim any unwatnted edges of the plastic products which have been created in the moulding process. Spin trimming would be used with wide bottle necks
Extrusion blow moulding (molding) - Heated plastic is extruded through a tube ending in a cool metal mould. This allows the plastic to cool down and then be released. Extrusion blow moulding can be intermittent meaning that the product moulds are filled separately, and then released when cool, or continuous, where the product is cut off with a knife at the top / bottom of the product,