Injection Stretch Blow Moulding Research Paper

Depending on the design, size and quantity of the stores to be manufactured, process for bulk production is selected. Most commonly used manufacturing processes include injection, blow, extrusion and compression moulding however a particular product may need a specific set of processes in order to achieve product in a cost effective and time bound manner. As an example, process for production of water bottles as per army requirement of quality and quantity, is described here.

The PC water bottle can be produced either by Extrusion blow moulding or by Injection Stretch Blow Moulding process. Both processes have its own advantage and limitations but Injection Stretch Blow Moulding process is recommended for manufacturing of these bottles because end product has excellent visual and dimensional quality especially of threads and neck portion, no pinch-off scrap, excellent thickness control and surface defects are very less.

5.3.1. Injection Stretch Blow Moulding Process

As the name suggests, Injection Stretch Blow Moulding is a combination of the two familiar process injection moulding and blow moulding. These processes can be carried out on a Single Stage Machine or a Double Stage Machine [51].

5.3.1.1. Single Stage Machine

Material Preparation: Material preparation and drying parameters have a particularly important influence on the quality of the finished product as well as lowering the rejection rates. Moisture can cause hydrostatic degradation of polymer during processing and shows up as streaks or small bubbles on the surface. The PC should have a residual moisture content no more than 0.02 %. It is dried at approximately 120°C for about 3 to 4 hours for high speed dryers and 2-3 Hours for dry air dryers before molding to ensure optimum processing, appearance and mechanical properties. Lower temperatures do not ensure sufficient level of drying and at higher temperature; there is risk of granules sticking together and being non suitable for