Container moulding arrangement
AssigneeAsp Plastics Pty Limited
InventorsMichael Patrick Leabeater, Peter Mandavy
Life of this patent
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Abstract
A method of injection moulding a plastics container 1 having wall(s) 2 of substantially uniform thickness using an injection mould 10 with an unsupported core 12 is disclosed. A small sliver 17 is removed from the free end of the core 12 of the mould 10 from that side of the wall which is thinnest. As a consequence on the next injection more plastic flows in that direction. Repeated optical inspection of the containers enables a balance to be achieved in which slightly asymmetric injection conditions are balanced by a slightly asymmetric container base with the result being a container with substantially uniform wall thickness.
Claims8
A method of injection moulding a container having side walls of substantially uniform thickness and a base from a mould having an interior and an unsupported core extending into said mould interior, said method comprising the steps of:
- (i) injection moulding a trial container and ejecting same from the mould;
- (ii) observing which portion of the side walls of said trial container is thinner than the remainder thereof;
- (iii) removing a small amount of material from a portion of said mould which forms the base of said container to slightly re-direct towards said thinner portion molten plastic entering said mould;
- (iv) repeating step (i);
- and
- (v) repeating steps (ii) to (iv) as necessary until said ejected trial container has substantially uniform side walls.
A method of injection moulding a finished container from a mould having an interior and an unsupported core that extends into said interior, the finished container having side walls of a substantially uniform thickness and a base, said method comprising the steps of:
- (i) injection moulding a trial container from a plastic material in said mould and removing said trial container from said mould, said trial container having side walls and a base;
- (ii) determining which portion of said side walls of said trial container is a thinner portion than a remainder thereof;
- (iii) removing a small amount of material from a portion of said mould that forms said base of said trial container so that in subsequent iterations of step (i), said plastic material is directed towards said thinner portion;
- (iv) repeating step (i);
- and
- (v) repeating steps (ii) to (iv), as necessary, until said trial container has substantially uniform side walls, thereby forming said finished container.
Dependencies are inferred from the claim text.