Blow Moulding Flashcards
What is blow moulding used for?
The process is used for the production of hollow glass and plastic objects in large amounts at a time
What is the process?
The plastic is injected onto a core pin, the core pin is then rotated to blow moulding station to be inflated and cooled
What are the three steps of blow moulding?
1) Injection
2) blowing
3) ejection
What happens during the blow moulding process?
The blow moulding machine melts the plastic, this is then put into a runner where it is injected through nozzles into a heated core pin. The mould then opens and the rod (that the plastic is clamped around) is rotated and clamped onto a hollow blow mould. The core rod then opens and allows air into preform inflating it.
What happens in the cooling process?
The blow mould opens and core rod rotates to the ejection position. The finished article is taken away and is tested for leaks.
What are advantages and disadvantages?
The advantage is that it creates and accurate injection mould.
The disadvantage is that it fits small bottles and is hard to control during the blowing.
What type of plastics are used in blow moulding?
The basic plastics are polythene, PVC and polypropylene.
