Expandable Tacky Tape for Composite Curing Pressure

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Solution Overview

Problem

In composite plastic curing, insufficient consolidation and conformation in difficult-to-reach areas of molds or forms result in defects due to inadequate pressure transmission from vacuum bags, primarily caused by bag/breather elongation and bridging deficiencies.

Innovation Solution

The use of an expandable tacky tape containing thermally expandable materials like microspheres or graphite dispersed in a high viscosity medium, such as butyl rubber or silicone, which expands during curing to transmit pressure and ensure composite material conforms accurately to the mold or form.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If vacuum bag consolidation is used for composite curing, then consolidation force is applied to the composite material, but bag/breather elongation and bridging deficiencies cause insufficient force transmission to difficult-to-reach areas

Engineering Contradiction:
Improveconsolidation forceVSAvoidconformation accuracy
Core Design Contradiction:
ForceVSManufacturing precision

Solution Approach 1:

The expandable tacky tape serves as an intermediary medium between the vacuum bag and the composite material in difficult-to-reach areas. It transmits consolidation force more effectively by expanding to fill gaps and maintain intimate contact with the composite surface, overcoming the bridging deficiencies of the vacuum bag system.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The tacky tape undergoes parameter changes through thermal expansion when heated during curing. This expansion increases its volume and contact pressure, transforming it from a passive layer to an active force transmission medium that delivers sufficient consolidation force to problem areas.

Inventive Principle:
Principle #35Parameter changes

2Force

If expandable medium is applied to problem areas, then sufficient pressure is applied during consolidation, but additional materials and process steps are required

Engineering Contradiction:
ImprovepressureVSAvoidprocess complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The invention merges multiple functions into a single material: the tacky tape provides both the expandable medium for pressure application and the release agent for easy removal. This combination eliminates the need for separate release films or additional processing steps, reducing overall process complexity despite the added functionality.

Inventive Principle:
Principle #5Merging (Combining)

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 solution effectively consolidates composite materials, reducing defects and improving conformation accuracy by applying controlled pressure through thermal expansion, ensuring the composite material conforms correctly to the desired shape during the curing process.

Implementation Method 1

When subsequently cured at increased temperature, the expansion within the tacky tape effectively transmits pressure sufficient to consolidate the composite material

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS10259925B2Expandable tacky tape
Publication Date: 2019.04.16 WALLEN MATT

AI summary

In the manufacture of composite product, raw composite is layered on a shape or form and cured at a higher temperature. With some shapes, it is difficult or impossible to apply sufficient pressure to force and consolidate the composite material to adequately conform to the desired final shape during the curing process. The expandable tacky tape of this invention is comprised of a viscous medium incorporating thermally expandable material. Applied over the raw composite, the expandable tacky tape effectively forces the composite to conform to the desired shape during curing.