Two-Component Dispenser Seam Structure for Impact Strength

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Dispensers made from multiple plastic components often experience distortion and seam weakness, particularly at side edges, leading to potential cracking under impact forces due to insufficient seam strength.

Innovation Solution

A two-component injection moulding process using a single mould to join plastic components with strategically moulded steps or projections along the seam, ensuring the seam's strength equals or exceeds that of the individual components, and controlling temperatures for effective melting and bonding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If two components are injection moulded separately and then joined, then manufacturing flexibility is improved, but seam strength deteriorates

Engineering Contradiction:
Improvemanufacturing flexibilityVSAvoidseam strength
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The first component is pre-formed with stepped edges before the second component is injected. These stepped edges are prepared in advance to receive and interlock with the second component, creating a strong mechanical bond that prevents seam failure under impact forces while maintaining the benefits of separate component manufacturing

Inventive Principle:
Principle #10Preliminary action

2Strength

If components are joined with local reinforcements, then seam strength is improved, but distortion increases

Engineering Contradiction:
Improveseam strengthVSAvoiddistortion
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The reinforcement structure consists of stepped edges located specifically at the joining interface between components. This localized geometric feature provides strength exactly where needed at the seam, while the rest of the components maintain their original dimensions and properties without unnecessary reinforcement that would cause distortion

Inventive Principle:
Principle #3Local quality

3Device complexity

If a single mould is used for two-component injection moulding, then manufacturing complexity is reduced, but temperature control difficulty increases

Engineering Contradiction:
Improvemould complexityVSAvoidtemperature control
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The single mould is divided into two separate cavities, allowing independent temperature control and injection parameters for each component. This segmentation enables the first and second components to be manufactured under optimized conditions for their respective materials while using a unified mould structure, balancing simplicity with control capability

Inventive Principle:
Principle #1Segmentation

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 enhanced impact strength, where the seam can withstand significant forces without cracking, ensuring the dispenser's integrity and longevity.

Implementation Method 1

a first component (a preform) is injected into a first mould... a second material is injected and overmoulded onto the perform

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

a second material is injected and overmoulded onto the perform to form a finished product, wherein the materials are joined along a continuous, circular seam

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP2310179B1Dispenser part manufactured by two-component injection moulding
Publication Date: 2016.06.22 SCA HYGIENE PRODUCTS AB
  • EP2310179B1 patent drawingFigure 1a~2
  • EP2310179B1 patent drawingFigure 3~4d
  • EP2310179B1 patent drawingFigure 5~6

AI summary

The invention relates to a dispenser part (20), comprising a first injection moulded plastic component part (17) with an associated first mating surface along a first edge; 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. A transverse cross section of the seam comprises at least one step and at least one contact surface intermediate an inner and an outer surface of the dispenser part.