Two-Shot Dispenser Part Moulding for Strong Impact Seams

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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, necessitating replacement.

Innovation Solution

A method involving two-component injection moulding where the first part is moulded in a single mould and then rotated for the second injection step, with raised contact surfaces or projections along the seam to enhance strength, using compatible resin materials and controlled temperatures to ensure a homogenous, strong seam.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If two components are injection moulded separately and then joined, then the dispenser part can be made from different plastic materials with different properties, but the seam becomes weak and prone to distortion and cracking

Engineering Contradiction:
Improvematerial selection flexibilityVSAvoidseam strength
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The patent merges two separate injection moulding processes into a single integrated tool that can mould both components in one operation. The tool includes first and second injection moulding means with respective cavities that form two components joined by a seam. This combining approach maintains seam strength while enabling different plastic materials to be used, resolving the contradiction between material versatility and seam strength.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of manufacture

If components are joined end-to-end with local reinforcements, then assembly is simplified, but the seam lacks sufficient strength to withstand impact forces

Engineering Contradiction:
Improveassembly simplicityVSAvoidimpact resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies local quality by providing specific reinforcement features at the seam location where strength is needed, rather than uniformly reinforcing the entire component. The reinforcement means are localized to the seam region to provide impact resistance while maintaining assembly simplicity elsewhere in the dispenser part.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If a transparent section is added to check consumable level, then product monitoring is improved, but the seam in that region becomes a weak point for cracking

Engineering Contradiction:
Improvelevel checking capabilityVSAvoidseam strength at side edges
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent applies local quality by providing targeted reinforcement at the seam regions, particularly at side edges where cracking is most likely to occur. This localized reinforcement allows transparent sections to be included for level checking while preventing the seam from becoming a weak point, as the reinforcement means specifically strengthen vulnerable areas without affecting the transparent monitoring regions.

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 produces dispenser parts with seams that match or exceed the impact strength of the individual components, preventing cracking along the seam and ensuring durability under impact.

Implementation Method 1

a first injection moulding step to form at least a first part

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

the mould is then moved or rotated to a second position in which the second injection step and the subsequent cooling is performed

Methodology Applied
Scientific EffectCooling: Cooling

Data Source

PatentEP2318192B1Method of making a dispenser or a part thereof
Publication Date: 2015.08.12 SCA HYGIENE PRODUCTS AB
  • EP2318192B1 patent drawingFigure 1a~2
  • EP2318192B1 patent drawingFigure 3~4d
  • EP2318192B1 patent drawingFigure 5~6

AI summary

The invention relates to a method for manufacturing a dispenser part (20), such as a dispenser or a part of a dispenser, comprising at least two component parts (17, 18) joined by a seam (21) extending from a first side edge to a second side edge of the dispenser part. The method involves using a single mould and producing the dispenser part using a two component injection moulding process. The invention further relates to a dispenser or a dispenser part including at least two component parts joined by a seam achieved by the method, and a component part used in such a dispenser or dispenser part.