Injection Mold Segmentation for Liquid-Tight Packaging Joints
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Solution Overview
Problem
Current methods for manufacturing cardboard-based packaging containers with liquid-tight joints face challenges such as appearance defects due to side wall displacement during plastic injection molding, leading to unsymmetrical flooding and increased manufacturing costs.
Innovation Solution
The method involves arranging the side walls to rest directly against the injection mold tool, with the plastic mass filled only inside the side walls and between joints, ensuring the packaging material is pressed against the outer mold half, preventing plastic from entering outside and stabilizing the container's position for defect-free joint formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the plastic mass is injected at high pressure to fill the cavities, then the liquid-tight joints are formed, but the side wall ends are displaced towards the inside or outside of the cavity causing appearance defects
Solution Approach 1:
The injection mold cavity is divided into two distinct parts: an inner cavity for receiving plastic mass to form joints, and an outer cavity for receiving packaging material. This segmentation prevents the plastic mass from displacing the side wall ends while ensuring complete filling of joint cavities, resolving the contradiction between forming liquid-tight joints and maintaining side wall end position.
Solution Approach 2:
The packaging material acts as an intermediary element between the injection mold tool and the plastic mass. By positioning the packaging material against the outer cavity of the mold tool, it stabilizes the side wall ends and prevents direct contact between high-pressure plastic mass and the mold tool walls, thereby eliminating appearance defects while ensuring proper joint formation.
2Stability of the object's composition
If the side walls are arranged to rest directly against the injection mold tool, then the packaging material is pressed towards the outer half stabilizing the container position, but the plastic mass filling becomes more controlled requiring precise mold design
Solution Approach 1:
The injection mold tool is segmented into an inner part and an outer part, with the packaging material positioned between them. This segmentation allows the packaging material to rest directly against the outer part for stabilization, while the inner part controls plastic mass filling independently, achieving stable container position with manageable mold design complexity.
Solution Approach 2:
The packaging material is pre-positioned against the outer cavity of the injection mold tool before plastic mass injection. This preliminary positioning ensures that when plastic mass is injected at high pressure, the packaging material is already in place to press against the outer half and stabilize the container, eliminating the need for complex real-time control mechanisms.
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 approach allows for the production of cost-effective, stackable, and environmentally friendly packaging containers with liquid-tight joints, eliminating appearance defects and enabling efficient manufacturing while using less plastic, thus reducing greenhouse gas contributions.
Implementation Method 1
The plastic mass is injected at high pressure which pushes the side wall ends to one or the other side of the cavity in the injection mold-tool
Implementation Method 2
The plastic mass is filled only on the inside of the side walls and between the joints but not at the outside of the side walls
Implementation Method 3
The packaging container, which by its conicity is stackable with equally shaped containers, consists of a cardboard based packaging material, preferably at least on one side coated with a heat sealable layer
Data Source
Figure 1
Figure 1b
Figure 2
AI summary
The invention relates to a method and a device for manufacturing a packaging container (1), which comprises a bottom (2) and from this bottom folded-up side walls (3-6), which during the manufacturing, are position orientated and fixed relative to each other in the erected state by liquid-tight joints in the form of a thermoplastic resin. The side walls (3-6) next to each other are fixable to each other by a liquid- tight joint in the form of a termoplastic at the same time as a circumferential container opening (11) of the packaging container comprises an opening edge (12) that also consists of thermoplastic, suitable for heat-sealable lid foil or for re-sealable lid, and said opening edge (12) integrally transforms into the thermoplastic uniting the side walls (3-6).