Soluble Polyimide Coating for Ceramic Tooling Inserts

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Solution Overview

Problem

Ceramic tooling inserts with porous surfaces pose challenges in molding composite parts due to adherence issues, leading to rough surface finishes and the need for labor-intensive and costly release films like polyimide film, which result in undesired marks and increased molding costs.

Innovation Solution

A high-temperature polyimide mold release coating is applied to the ceramic tooling inserts, formed by a solution of polyamic acid monomers, which is applied and dried to create a smooth, low-surface-tension layer that fills surface irregularities and allows easy removal of the insert after molding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a release film is applied to ceramic tooling inserts, then adhesion prevention is improved, but manufacturing complexity and cost increase

Engineering Contradiction:

Improveadhesion preventionVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The porous ceramic insert is pre-coated with a solvable material before molding operations. This preliminary coating action eliminates the need for subsequent release films, reducing manufacturing complexity while maintaining adhesion prevention during the actual molding process

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A solvable material acts as an intermediary between the porous ceramic insert and the composite material. This intermediary layer prevents direct adhesion between the composite and ceramic surfaces, while being designed to dissolve after molding, simplifying the overall system

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a release film is applied to ceramic tooling inserts, then adhesion prevention is improved, but surface finish quality deteriorates due to mark-off

Engineering Contradiction:

Improveadhesion preventionVSAvoidsurface finish quality

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The porous ceramic insert is pre-coated with a solvable material that fills surface irregularities and creates a smooth interface. This preliminary action prevents mark-off on the final part surface while maintaining adhesion prevention during molding

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The solvable material serves as an intermediary that not only prevents adhesion but also smooths out surface irregularities of the porous ceramic, eliminating the mark-off problem that occurs with traditional release films

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If hand-wrapping with release film is performed, then adhesion prevention is improved, but productivity decreases due to labor-intensive process

Engineering Contradiction:

Improveadhesion preventionVSAvoidmolding cycle efficiency

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The porous ceramic inserts are pre-coated with solvable material in advance, allowing multiple inserts to be prepared simultaneously. This eliminates the need for time-consuming hand-wrapping of each insert during molding operations, significantly improving productivity

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The solvable material intermediary is applied in a efficient pre-coating process that can handle multiple inserts at once, replacing the labor-intensive hand-wrapping method and enabling faster production cycles

Inventive Principle:

Principle #24Intermediary (Mediator)

4Reliability

If polyimide release film is used, then adhesion prevention is improved, but cost increases

Engineering Contradiction:

Improveadhesion preventionVSAvoidmolding cost

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

Instead of using expensive polyimide release films that need to be repeatedly applied and removed, the patent uses a solvable material that is disposed of after a single use by dissolving it. This eliminates the recurring cost of expensive release films while maintaining adhesion prevention during molding

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The solvable material is deliberately designed to be discarded through dissolution after the molding process completes its function. This eliminates the need to recover and reuse expensive polyimide films, reducing overall molding costs while maintaining effective adhesion prevention

Inventive Principle:

Principle #34Discarding and recovering

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 coating provides a smooth surface finish to the molded parts, reduces adhesion, and facilitates easy removal of the tooling insert, eliminating the need for labor-intensive film wrapping and minimizing costs by ensuring a seamless surface and efficient molding process.

Implementation Method 1

removing solvent from the solution by drying

Methodology Applied

Scientific EffectEvaporation: Evaporation

Implementation Method 2

converting the polyamic acid placed on the tool surface to polyimide by heating the mold tool

Methodology Applied

Scientific EffectThermal decomposition: Pyrolysis

Implementation Method 3

The coating has, preferentially, a low surface tension, allowing it to release from the formed plastic part

Methodology Applied

Scientific EffectSurface tension: Surface Tension

Data Source

PatentUS10538019B2Coating soluble tooling inserts

Publication Date: 2020.01.21 THE BOEING CO

AI summary

The surface of a tooling insert is coated with a polymer layer having a low surface energy in order to cover surface irregularities and thereby provide a smooth surface against which a composite part may be compression molded.