Two-Component Dispenser Part Seam Structure for Impact Strength

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Solution Overview

Problem

Dispenser parts made from multiple plastic materials often suffer from distortion and weak seams, particularly at side edges, which can lead to cracking under impact forces, compromising their structural integrity and requiring frequent replacement.

Innovation Solution

A two-component injection moulding process is used to create dispenser parts with a seam extending from one side edge to another, employing raised contact surfaces or projections along the seam to enhance strength, where the first component is moulded with steps or projections that melt during the second injection step, ensuring a homogenous and strong bond between materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If two components are injection moulded and joined along a seam, then the dispenser part can have different material properties (transparent/opaque sections), but the seam lacks sufficient strength to withstand impact forces

Engineering Contradiction:
Improvematerial property variationVSAvoidseam strength
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The patent applies local quality by creating a seam with non-uniform thickness, where the seam thickness varies along its length. The seam is thicker in regions subjected to higher impact forces (such as corners and edges) and thinner in less critical areas. This localized variation in seam thickness provides enhanced strength where needed while maintaining overall structural integrity and allowing different material properties in different sections of the dispenser part.

Inventive Principle:
Principle #3Local quality

2Strength

If the seam is reinforced locally to increase strength, then the seam can withstand more force, but the dispenser part becomes more complex to manufacture

Engineering Contradiction:
Improveseam strengthVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent employs parameter changes by varying the seam thickness as a continuous parameter along the seam length rather than using discrete reinforcements. The seam thickness is adjusted based on the expected impact forces at different locations, creating a gradient structure that optimizes strength while avoiding the complexity of multiple separate reinforcement components. This continuous parameter variation is achieved through controlled injection moulding processes.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If the seam extends from one side edge to another side edge, then the dispenser part can be made from two similar or different plastic materials with different functions, but the seam becomes vulnerable to distortion and cracking

Engineering Contradiction:
Improvefunctional differentiationVSAvoidseam reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies local quality by creating a seam with non-uniform thickness, where the seam thickness varies along its length. The seam is thicker in regions subjected to higher impact forces (such as corners and edges) and thinner in less critical areas. This localized variation in seam thickness provides enhanced strength where needed while maintaining overall structural integrity and allowing different material properties in different sections of the dispenser part.

Inventive Principle:
Principle #3Local quality

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

The method results in a dispenser part with a seam that matches or exceeds the impact strength of the individual components, preventing cracks along the seam and ensuring the dispenser part fractures away from the seam under impact, thus improving durability and reducing replacement needs.

Implementation Method 1

employing raised contact surfaces or projections along the seam to enhance strength, where the first component is moulded with steps or projections that melt during the second injection step

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP2313243B1Two-component injection moulded dispenser part
Publication Date: 2016.12.07 SCA HYGIENE PRODUCTS AB
  • EP2313243B1 patent drawingFigure 1a~2
  • EP2313243B1 patent drawingFigure 3~4d
  • EP2313243B1 patent drawingFigure 5~6

AI summary

The invention relates to a dispenser part, comprising a first injection moulded plastic component part (17) with an associated first mating surface; a second injection moulded plastic component part (18) having an associated second mating surface; a seam (21) formed by said first mating surface and said second mating surface during injection moulding for joining said first component part and said second component part to define a dispenser part, and component part comprising a front surface, a first and a second side surface each having an edge (22, 23) facing away from the front surface. The resulting seam extends from the edge (22) associated with the first side surface to the edge (23) associated with the second side surface.