Cellulose Honeycomb Core Sandwich Component

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Solution Overview

Problem

Current methods for producing sandwich components with honeycomb cores are costly and unsuitable for mass production due to high material costs and complex manufacturing processes, which limits their application in lightweight construction, particularly in motor vehicle manufacturing.

Innovation Solution

A method using a cellulose-based honeycomb core with a thermoplastic matrix and fiber-reinforced semi-finished products to create sandwich components, where the thermoplastic matrix bonds with the honeycomb core, eliminating the need for additional adhesives and allowing for simpler, cost-effective production in large quantities with reduced cycle times.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If high-quality aramid paper impregnated with phenolic resin is used for the honeycomb core, then the strength and rigidity of the sandwich component are improved, but the material cost increases significantly

Engineering Contradiction:
Improvestrength and rigidity of sandwich componentVSAvoidmaterial cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent changes the material parameters by using cellulose-based honeycomb cores with thermoplastic matrices instead of traditional aramid paper with phenolic resin. This substitution maintains structural performance while dramatically reducing material costs and enabling automated manufacturing processes.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs inexpensive cellulose-based materials for the honeycomb core that can be rapidly manufactured and processed. These materials provide sufficient structural performance at lower cost, allowing for high-volume production in automotive applications where cost efficiency is critical.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Manufacturing precision

If autoclave method or hand lamination is used for manufacturing, then the quality of sandwich components is improved, but the production time and cost increase, making them unsuitable for mass production

Engineering Contradiction:
Improvequality of sandwich componentVSAvoidproduction quantity and cycle time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent replaces complex mechanical manufacturing processes like autoclave method and hand lamination with simpler, more efficient automated processes. The thermoplastic matrix enables rapid bonding and consolidation, eliminating the need for prolonged high-pressure autoclave curing and manual layer-by-layer assembly.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes phase transition of thermoplastic materials from solid to molten state and back during processing. This allows for rapid bonding of honeycomb cores and cover layers through heating and cooling cycles, dramatically reducing production time compared to thermosetting materials that require extended curing periods.

Inventive Principle:
Principle #36Phase transitions

3Strength

If additional adhesives or binding agents are used to bond the cover layer with the honeycomb core, then the bonding strength is improved, but the production complexity and cost increase

Engineering Contradiction:
Improvebonding strength between cover layer and honeycomb coreVSAvoidproduction process complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent merges the bonding function with the structural material itself by using a thermoplastic matrix in the honeycomb core that inherently bonds to the cover layer during processing. This eliminates the need for separate adhesive applications and curing steps, simplifying the manufacturing process while maintaining strong bonds.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The thermoplastic matrix in the honeycomb core provides self-bonding capability to the cover layers through its inherent melting and solidification characteristics. The material serves both structural and bonding functions simultaneously, eliminating the need for additional binding agents and reducing production complexity.

Inventive Principle:
Principle #25Self-service

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 enables the production of lightweight sandwich components with improved mechanical properties and surface quality, suitable for various motor vehicle components, while reducing material and production costs, and allowing for complex shapes and large-scale manufacturing.

Implementation Method 1

the thermoplastic matrix bonds with the honeycomb core, eliminating the need for additional adhesives

Methodology Applied
Scientific EffectThermal bonding: Heating

Implementation Method 2

the thermoplastic matrix of the semi-finished product, which is exposed to a temperature between the glass transition temperature and the melting temperature of the plastic, melts at least partially in the areas of increased pressure

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP2525962B1Sandwich component and method for the production thereof
Publication Date: 2015.04.15 MERCEDES BENZ GROUP AG
  • EP2525962B1 patent drawingFigure 1a~3b
  • EP2525962B1 patent drawingFigure 4~5
  • EP2525962B1 patent drawingFigure 6~7

AI summary

The present invention relates to a sandwich component, which comprises a honeycomb core (1) having a plurality of webs (1') and at least one cover layer (2, 3), wherein the honeycomb core (1) is made of a cellulose-based material, in particular paper. The cover layer (2, 3) is formed from a fiber-reinforced semifinished product having a thermoplastic material matrix, wherein the webs (1') of the honeycomb core (1) are partially received into the thermoplastic material matrix of the cover layer (2, 3) at connection points (A) to the cover layer (2, 3) so that the sandwich component is bonded. The invention further relates to production methods for the sandwich component.