Thin-Wall Appliance Components Using Cascaded Injection Molding

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Solution Overview

Problem

Conventional injection molding techniques for producing large household appliance components with flat or flat design over large areas face challenges due to high wall thickness requirements, leading to excessive locking forces, prolonged cooling times, and inefficiencies, making them economically unviable.

Innovation Solution

The method combines thin-wall injection molding and cascade injection molding with multiple injection points to reduce wall thickness, allowing for lower locking forces and faster cooling, enabling the use of conventional injection molding tools and machines.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional injection molding is used for large household appliance components, then the component can be manufactured with sufficient structural integrity, but the wall thickness must be significantly higher than 1.5 mm resulting in excessive locking forces and prolonged cooling times

Engineering Contradiction:
Improvewall thickness controlVSAvoidlocking forces
Core Design Contradiction:
Manufacturing precisionVSForce

Solution Approach 1:

The injection molding process is segmented into multiple phases using cascade injection molding with multiple injection points. The melt is injected in sequences from different locations simultaneously, allowing thin-walled large components to be filled uniformly without requiring excessive locking forces. This segmentation of the injection process enables precise wall thickness control while reducing the overall force requirement.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from single-point sequential injection to multi-point simultaneous injection by adding spatial dimensionality to the injection process. Multiple injection points are distributed across the mold cavity, injecting melt in different directions and sequences, which enables thin-walled large components to be formed uniformly without excessive locking forces.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Force

If wall thickness is reduced to decrease locking forces, then locking forces are reduced, but a single injection point causes premature hardening and insufficient melt distribution requiring high injection pressure which increases locking forces

Engineering Contradiction:
Improvelocking forcesVSAvoidmelt distribution uniformity
Core Design Contradiction:
ForceVSManufacturing precision

Solution Approach 1:

The injection system is segmented into multiple injection points distributed across the mold cavity. Each injection point delivers melt to specific regions simultaneously, ensuring uniform melt distribution throughout the large component. This segmentation prevents premature hardening at any single location and maintains consistent wall thickness without requiring high injection pressure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cascade injection molding process maintains continuous useful action by coordinating multiple injection points to deliver melt continuously and simultaneously to different regions of the mold cavity. This continuous multi-point injection ensures that the entire component fills uniformly before hardening begins, maintaining melt distribution uniformity while using lower injection pressure.

Inventive Principle:
Principle #20Continuity of useful action

3Device complexity

If conventional injection molding with single injection point is used, then the process is simple, but cooling time is very long for large components

Engineering Contradiction:
Improveinjection process complexityVSAvoidcooling time
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The cooling process is segmented and parallelized by using multiple injection points that create more uniform and thinner walls throughout the component. Thinner walls cool faster, significantly reducing cooling time. The segmentation of the injection process into coordinated sequences at multiple points enables this time reduction while maintaining manageable process complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

By adding the dimension of multiple injection points distributed in space, the process creates more uniform wall thickness distribution across the large component. This spatial distribution of injection points enables faster cooling throughout the entire component while the coordinated cascade sequencing keeps the control complexity manageable.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Force

If thin-wall injection molding is used with multiple injection points, then locking forces are reduced and cooling time is shortened, but the process complexity increases

Engineering Contradiction:
Improvelocking forcesVSAvoidinjection molding process complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The injection process is segmented into coordinated sequences at multiple injection points, where each point operates in a specific sequence to fill the mold cavity. This segmentation enables thin-wall formation with reduced locking forces while the systematic sequencing of segments keeps the overall process complexity manageable through structured control.

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

This approach results in reduced locking forces, shorter cooling times, and more efficient production of large household appliance components with thin walls, enhancing manufacturing precision and reducing production costs.

Implementation Method 1

the household appliance component is manufactured by injection molding

Methodology Applied
Scientific EffectInjection molding:

Implementation Method 2

the injected melt has already solidified in some areas, while in others it has not yet solidified

Methodology Applied
Scientific EffectCooling: Cooling

Data Source

PatentEP3380798B1A method for producing a component of a household appliance by a combined molding process of the thin wall injection molding and the cascaded injection molding as well as a component of a household appliance
Publication Date: 2022.08.24 BSH HAUSGERATE GMBH
  • EP3380798B1 patent drawingFigure 1~3
  • EP3380798B1 patent drawingFigure 4~6
  • EP3380798B1 patent drawingFigure 7~9

AI summary

The invention relates to a method for manufacturing a component (6) for a home appliance (1), wherein the home appliance component (6) is made from plastic in an injection molding process, during at least some phases of which a combination of the thin-wall injection molding technique and the cascade molding technique is used. The invention also relates to a home appliance component (6).