Thermoplastic Charge Preheating via Heated Gas Flow

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Solution Overview

Problem

The rate of producing composite parts through compression molding of thermoplastic composite materials is limited by the long thermal cycle time required to heat the compression mold and the thermoplastic material to a molding temperature.

Innovation Solution

A system and method for preheating a thermoplastic charge using a conduit with a gas moving unit and a heating assembly to heat a gas-particulate mixture, which includes a thermoplastic particulate material, allowing the preheated mixture to be introduced into a mold for compression molding, thereby reducing thermal cycle time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional compression molding is used to heat thermoplastic composite material to molding temperature, then the material reaches the required temperature for molding, but the thermal cycle time becomes excessively long, limiting production rate

Engineering Contradiction:

Improvemolding temperatureVSAvoidthermal cycle time

Core Design Contradiction:

TemperatureVSLoss of time

Solution Approach 1:

The patent applies preliminary action by preheating the thermoplastic charge material to a significant portion of the molding temperature (e.g., 80-90% of final molding temperature) before it enters the compression mold. This is achieved through a preheating system that heats the material in advance using heated air or gas flow, so that when the material enters the mold, only minimal additional heating is required, dramatically reducing the thermal cycle time while maintaining the required molding temperature

Inventive Principle:

Principle #10Preliminary action

2Productivity

If the compression mold and thermoplastic material are heated to molding temperature using conventional methods, then the material is ready for molding, but the production rate remains low due to long thermal cycle times

Engineering Contradiction:

Improveproduction rateVSAvoidthermal cycle time

Core Design Contradiction:

ProductivityVSDuration of action of stationary object

Solution Approach 1:

The system performs preliminary heating of the thermoplastic charge material outside the mold using a preheating chamber with heated air circulation. This advance preparation ensures the material reaches near-molding temperature before entering the compression mold, so the mold heating time is significantly reduced, thereby increasing production rate without compromising the thermal cycle requirements

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary heating medium (heated air or gas) that transfers thermal energy to the thermoplastic charge material in the preheating chamber. This intermediary medium allows efficient and uniform heat distribution to the material before molding, reducing the overall thermal cycle time and enabling faster production cycles

Inventive Principle:

Principle #24Intermediary (Mediator)

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 preheating process significantly reduces the time needed to bring the thermoplastic material to the molding temperature, enhancing the efficiency of the compression molding operation.

Implementation Method 1

a heating assembly positioned between the inlet and the outlet to heat the gas moving through the conduit

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

inducing a magnetic field using an induction coil surrounding a conduit; heating a susceptor, positioned in the magnetic field between the induction coil and at least one of a gas and a gas-particulate mixture

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

heating a susceptor, positioned in the magnetic field between the induction coil and at least one of a gas and a gas-particulate mixture moving through the conduit

Methodology Applied

Scientific EffectEddy currents: Eddy Currents

Implementation Method 4

heating at least one of the gas and the gas-particulate mixture by one of: contacting at least one of the gas and the gas-particulate mixture with the susceptor

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS10981296B2System and method for preheating a thermoplastic charge

Publication Date: 2021.04.20 THE BOEING CO

AI summary

A system and method for preheating a thermoplastic charge are disclosed. A gas moving unit establishes a flow of a gas through a conduit. A heating assembly is positioned between an inlet and an outlet of the conduit. A holding vessel is in fluid communication with the conduit and houses a thermoplastic particulate material. The thermoplastic particulate material includes a thermoplastic matrix material. The thermoplastic particulate material is introduced to the flow of the gas to yield a gas-particulate mixture. At least one of the gas and the gas-particulate mixture, moving through the conduit, is heated using the heating assembly to yield a heated gas-particulate mixture. The heated gas-particulate mixture is deposited into a mold from the outlet of the conduit.