Inner Mold Tool Bushing for Injection Molding Alignment
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Solution Overview
Problem
High-speed injection moulding processes in the packaging industry face issues with misalignment and wear of outer mould tools, leading to burrs and reduced mould tool lifespan, particularly in producing plastic tops for liquid food packages.
Innovation Solution
An inner mould tool with a bushing having a planar surface and side walls is used, supported by springs to extend longitudinally, providing increased contact area and guiding the outer mould tools in a horizontal plane, reducing wear and burr formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the outer mould tools are made of aluminum for fast cooling in high-speed injection moulding, then the cooling speed and productivity are improved, but the wear resistance and lifespan of the mould tools deteriorate due to misalignment
Solution Approach 1:
A bushing is introduced as an intermediary component between the inner mould tool and the outer mould tools. The bushing provides a precise mating surface that guides the outer mould tools, ensuring accurate alignment during high-speed injection moulding. This intermediary element protects the outer mould tools from wear while maintaining the fast cooling capability of aluminum construction
Solution Approach 2:
The bushing is pre-installed on the inner mould tool with precisely machined surfaces that establish the correct alignment position before the outer mould tools engage. This preliminary positioning action ensures that when injection moulding occurs at high speed, the outer mould tools are already correctly aligned, preventing misalignment-induced wear
2Productivity
If the outer mould tools are moved quickly to reach operational position for high-speed production, then the productivity is improved, but the alignment precision deteriorates causing burr formation
Solution Approach 1:
The bushing acts as a guiding intermediary that the outer mould tools contact during their rapid movement. The planar surface and side walls of the bushing provide physical guidance that maintains precise alignment even at high speeds, preventing the outer mould tools from deviating and causing burrs
Solution Approach 2:
The bushing with its precisely engineered planar surface and side walls is installed in advance to cushion and guide the outer mould tools during their high-speed approach. This pre-positioned guidance structure absorbs any alignment errors that might occur during rapid movement, ensuring precise positioning at the moment of injection
3Manufacturing precision
If the bushing planar surface is made larger to increase contact area with outer mould tools, then the guidance and alignment are improved, but the device complexity increases
Solution Approach 1:
Instead of making the entire bushing complex, the invention applies local quality by providing a precisely finished planar surface and side walls only at the specific locations where contact with outer mould tools occurs. The rest of the bushing structure can be simpler, reducing overall complexity while maintaining high guidance accuracy at the critical contact interfaces
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances the alignment and guidance of outer mould tools, reducing wear and extending the lifespan of mould tools while minimizing burrs, ensuring safer and more reliable packaging production.
Implementation Method 1
The bushing may be supported by at least one spring biasing the bushing to a longitudinally extended position
Data Source
AI summary
An inner mould tool forming part of a mould to be used during injection moulding of plastic articles, such as plastic tops for liquid food packages, is provided. The inner mould tool comprises an outer surface defining the interior surface of the plastic article to be produced, wherein the longitudinal end of the inner mould tool is provided with a bushing having a planar surface defining the longitudinal end of the inner mould tool and being configured to be in contact with mating outer mould tools during injection moulding. The bushing is provided with side walls extending from the planar surface, said side walls forming part of the outer surface of the inner mould tool.