Injection Mould Inserts for Peel-off and Flex-off Lids
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Solution Overview
Problem
The conventional method of producing injection moulded plastics packaging products requires a high number of different moulds for 'peel-off' and 'flex-off' lid types, leading to increased production costs and maintenance burdens.
Innovation Solution
Designing a method where both 'peel-off' and 'flex-off' lids share the same overall dimensions, allowing them to be produced using the same injection moulds with modifications for reduced wall thickness and minor design differences, enabling the same mould to produce both types of lids for a given bucket size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If separate injection moulds are used for 'peel-off' and 'flex-off' lid types, then each lid type can be produced with optimized design, but the number of moulds increases significantly leading to higher production costs and maintenance burdens
Solution Approach 1:
The patent applies universality by designing a single injection mould that can produce both 'peel-off' and 'flex-off' lid types. The mould includes a base cavity for common lid features and interchangeable inserts that define the specific lid type characteristics. This allows one mould to serve multiple functions, eliminating the need for separate moulds for each lid type while maintaining the ability to produce both varieties.
Solution Approach 2:
The injection mould is segmented into a base cavity containing common lid features and separate interchangeable inserts that define the specific lid type. This segmentation allows the mould to be reconfigured by swapping inserts rather than using entirely separate moulds, reducing the total number of moulds needed while preserving design optimization for each lid type.
2Manufacturing precision
If separate production lines are used for different lid types, then each line can be optimized for its specific lid type, but production costs and maintenance requirements increase
Solution Approach 1:
The patent makes the production line universal by equipping it with a single injection mould that can produce both lid types through interchangeable inserts. This eliminates the need for separate production lines while maintaining the ability to produce lid types with manufacturing precision optimized for their specific requirements.
3Productivity
If multiple specialised moulds are maintained, then each lid type can be produced efficiently, but mould replacement and maintenance frequency increases
Solution Approach 1:
The mould is segmented into a durable base cavity and replaceable inserts. The base cavity, which undergoes the most wear, remains fixed and robust, while only the inserts need to be replaced or maintained. This segmentation reduces the overall maintenance burden compared to maintaining multiple complete specialised moulds, as only the insert components require frequent attention.
Solution Approach 2:
The patent implements a system where inserts can be easily replaced when worn or when changing lid type production. Rather than maintaining multiple complete moulds, the system recovers and reuses the base cavity structure, only discarding and replacing the consumable insert components, thereby reducing maintenance burden.
Data Source
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AI summary
When practicing the present invention, the manufacturer as an initial step, and starting from a given bucket 10, selects the thickness w30 of a second type lid 30 circumferential region 31 to be less than the thickness w20 of a first type lid 20 circumferential region 21 whereby the circumferential flange 38 of the second type lid 30 after application on the bucket 10 is more readily manually disengaged from said locking rib 16 by an outward flexural movement of the outermost wall 37. Hence, the second type lid 30 may conveniently be formed as a "flex-off'-type lid fitting the same bucket 10 as the first type lid 20. Making lids of the second type may be by using the same injection mold as used for the first type lid 20, modified by an inlay providing for the reduced wall thickness w30 and possibly for any minor differences in the design of the peripheral flanges 28, 38, such as the angle θ that the upper face A of the flange 28, 38 makes with the vertical, and the dimension a, i.e. the width of the peripheral flange 28, 38.