Reusable Cartridge for RTM Resin Injection

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Solution Overview

Problem

Current Resin Transfer Molding (RTM) methods face challenges in achieving high production rates due to complex and time-consuming operations, frequent solvent-based cleanings, lack of resin degassing capabilities, safety concerns for workers, and process variability affecting part quality.

Innovation Solution

A cartridge-based system for resin injection that includes a cylindrical cartridge with a piston and locking mechanism, allowing for efficient resin handling, degassing, and cleaning, reducing manual operations and exposure to solvents, while maintaining precise control over resin flow and pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If manual loading, degassing, and cleaning of resin is performed using traditional PD injectors or pressure pots, then resin injection can be achieved, but additional process time is required and operator exposure to resin and solvents increases

Engineering Contradiction:
Improveproduction rateVSAvoidinjection processing time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The injection system is divided into separate functional modules: a reusable cartridge that can be quickly exchanged, a resin storage container, and an injection mechanism. This segmentation allows the cartridge to be pre-filled and prepped separately, enabling parallel processing and reducing overall cycle time while minimizing operator exposure during critical injection phases.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Resin is loaded into the cartridge container and degassed in advance before the actual injection process. The cartridge is prepared, sealed, and ready for immediate use, eliminating the need for time-consuming manual loading and degassing operations during production cycles.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If frequent solvent-based cleaning is performed on injection systems, then resin buildup is removed, but operator exposure to solvents increases and additional process time is consumed

Engineering Contradiction:
Improveinjection system cleanlinessVSAvoidoperator exposure to solvents
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The cartridge is designed as a disposable or limited-life component that is discarded after a certain number of uses or when contamination occurs. This eliminates the need for frequent solvent-based cleaning of the entire injection system, reducing both time loss and operator exposure to harmful solvents while maintaining injection reliability.

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

Solution Approach 2:

The potentially contaminated cartridge is extracted and removed from the injection system as a separate unit. This isolates the contamination issue to a removable component, allowing the main injection system to remain clean without requiring extensive solvent cleaning operations.

Inventive Principle:
Principle #2Taking out (Extraction)

3Productivity

If traditional injection systems are used, then resin injection is achieved, but complex operations and lack of automation affect production efficiency

Engineering Contradiction:
Improveproduction rateVSAvoidmanual operations
Core Design Contradiction:
ProductivityVSExtent of automation

Solution Approach 1:

The cartridge system is designed to be self-contained and self-explanatory, with features like alignment guides, snap-fit connections, and visual indicators that enable quick changeover without requiring complex manual operations or extensive operator training. The system serves itself through standardized interfaces that minimize the need for manual adjustment.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The cartridge design incorporates universal features that allow it to work with different resin types and injection parameters. The standardized interface and modular design enable the same basic system to handle multiple product variations, reducing the need for complex reconfiguration and manual operations when changing production runs.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Manufacturing precision

If process variability is present in traditional injection systems, then part quality consistency is affected, but automation and control can improve consistency

Engineering Contradiction:
Improvepart quality consistencyVSAvoidautomation control system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The cartridge design incorporates features that standardize critical parameters such as resin volume, pressure, and temperature control. By pre-configuring these parameters in the cartridge design itself rather than relying on complex real-time adjustments, the system achieves consistent part quality without requiring overly complex automation control systems.

Inventive Principle:
Principle #35Parameter changes

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 cartridge system enhances RTM production efficiency by reducing cycle time, improving resin handling safety, and ensuring consistent part quality through automated processes and reduced solvent use, supporting higher production rates without compromising mechanical properties.

Implementation Method 1

The piston is connected to an actuator which translates the piston up the cartridge displacing resin out and into the mold

Methodology Applied
Scientific EffectPressure: Pressure Increase

Implementation Method 2

sealing resin from leakage at typical process temperatures of 250°F (∼120°C), injection pressures of 250 psi (∼1.7 MPa), and vacuum greater than 1 torr (∼100 Pa)

Methodology Applied
Scientific EffectVacuum sealing: Vacuum

Implementation Method 3

A high vacuum is typically applied to the mold before and during injection to improve part quality and resin flow throughout the mold

Methodology Applied
Scientific EffectVacuum: Vacuum

Data Source

PatentEP2814652B1Reusable cartridge for injection molding
Publication Date: 2019.06.19 RADIUS ENG INC
  • EP2814652B1 patent drawingFigure 1~3
  • EP2814652B1 patent drawingFigure 4~5
  • EP2814652B1 patent drawingFigure 6~7

AI summary

Reusable cartridges allow the time consuming resin preparation and processing steps to occur offline and not affect the cycling time of the injector. Cartridges also greatly simplify the operation of RTM injectors as preparation simply consists of loading a warmed ready-to-use resin cartridge and performing the injection.