SMC Hollow Components Using Leachable Salt Cores

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Solution Overview

Problem

Current methods for producing fiber composite hollow components, such as SMC and high-pressure RTM processes, face challenges like increased component weight due to non-removable cores, limited shape complexity, and high production costs, which hinder lightweight construction and efficient large-scale automobile production.

Innovation Solution

The method involves using a salt-based core system in the SMC process, which provides sufficient pressure and heat resistance, allowing for the production of complex hollow profiles with removable cores, reducing manufacturing complexity and costs, and enabling economic large-scale production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If high-density foam cores are used in high-pressure RTM process, then pressure resistance is improved, but component weight increases

Engineering Contradiction:
Improvepressure resistanceVSAvoidcomponent weight
Core Design Contradiction:
Stress or pressureVSWeight of moving object

Solution Approach 1:

The patent uses salt cores that can be easily dissolved and removed after molding, replacing permanent high-density foam cores. The salt cores serve their purpose during molding (maintaining shape and withstanding pressure) and then are completely removed through dissolution, eliminating the need for heavy permanent core structures.

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

Solution Approach 2:

The patent changes the physical-chemical parameters of the core material by using salt that can undergo phase change from solid to dissolved state. This allows the core to maintain structural integrity during high-pressure molding, then be easily removed through dissolution, achieving both pressure resistance and weight reduction.

Inventive Principle:
Principle #35Parameter changes

2Weight of moving object

If blow-molded cores are used, then component weight is reduced through core removal, but process complexity increases

Engineering Contradiction:
Improvecomponent weightVSAvoidprocess complexity
Core Design Contradiction:
Weight of moving objectVSDevice complexity

Solution Approach 1:

The salt cores are designed as disposable elements that are easily removed through dissolution. This simplifies the overall process compared to blow-molded cores, which require complex removal procedures. The salt cores dissolve automatically, eliminating the need for complex extraction mechanisms.

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

Solution Approach 2:

The patent replaces mechanical core removal systems (required for blow-molded cores) with a chemical dissolution process. Instead of mechanically extracting complex blow-molded cores, the salt cores are simply dissolved using water or appropriate solvents, dramatically simplifying the removal process.

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

3Productivity

If extrusion process is used, then production efficiency is improved, but shape complexity is limited

Engineering Contradiction:
Improveproduction efficiencyVSAvoidshape complexity
Core Design Contradiction:
ProductivityVSShape

Solution Approach 1:

The patent uses segmented salt cores that can be arranged in various configurations to create complex hollow geometries. These modular cores allow the production of intricate shapes with multiple cavities and varying cross-sections, overcoming the limitations of conventional extrusion while maintaining continuous production capabilities.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent enables dynamic shape changes during the molding process by using flexible SMC material that can be molded around the salt cores into complex geometries. The material flows and adapts to the core configuration, allowing production of shapes with significant cross-sectional changes that would be impossible with rigid extrusion.

Inventive Principle:
Principle #15Dynamics

4Ease of manufacture

If SMC process with traditional cores is used, then manufacturing simplicity is maintained, but core removal difficulty increases

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidcore removal complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The salt cores are designed as easily removable disposable elements that dissolve after serving their molding function. This eliminates the complexity of core removal while maintaining the simplicity of the SMC manufacturing process. The cores are cheap and their removal through dissolution requires no complex equipment or procedures.

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

Solution Approach 2:

The patent replaces mechanical core removal operations with a simple dissolution process. Instead of requiring complex mechanical extraction systems, the salt cores are dissolved using water or appropriate solvents, maintaining manufacturing simplicity while eliminating core removal difficulty.

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

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 economical production of lightweight fiber composite hollow components with complex geometries, reducing production costs and increasing design freedom, while ensuring high pressure resistance and ease of core removal, thus enhancing process reliability and economic advantages.

Implementation Method 1

the salt exhibits sufficient pressure and heat resistance for the SMC tool

Methodology Applied
Scientific EffectPressure resistance:

Implementation Method 2

the salt exhibits sufficient pressure and heat resistance for the SMC tool

Methodology Applied
Scientific EffectHeat resistance:

Implementation Method 3

an SMC-suitable fiber composite semi-finished product is arranged in an SMC tool over or around a core system and is pressed into a hollow shape by the SMC tool

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 4

the simple, quick and cost-effective removal of the core by its washing out according to the invention after component production

Methodology Applied
Scientific EffectWashing out:

Data Source

PatentEP3302946B1Process for the production of smc hollow components
Publication Date: 2019.03.06 BAYERISCHE MOTOREN WERKE AG

AI summary

The invention relates to a process for the production of fiber composite hollow components, wherein a SMC-suitable fiber composite semi-finished product is arranged in a SMC tool above or around a core system and is pressed into a hollow mold by the SMC tool, the core system being formed from a leachable saline base.