Foam Casting Process for Customized Biocompatible Shapes

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current casting processes for foams lack the capability to produce customized and complex shapes, especially for biocompatible materials intended for permanent implantation in the human body.

Innovation Solution

The described process combines salt-leaching and solvent casting techniques to synthesize foams using pre-polymerized polymer pellets, allowing for the creation of foams with controlled porosity and integration of additional materials like a mesh or film.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If conventional casting processes are used, then manufacturing simplicity is maintained, but the capability to produce customized and complex shapes is lost

Engineering Contradiction:

Improvecomplex shape capabilityVSAvoidprocess complexity

Core Design Contradiction:

ShapeVSDevice complexity

Solution Approach 1:

The process segments the foam fabrication into distinct phases: salt-leaching to create porous structure, followed by solvent casting to form the final foam shape. This segmentation enables complex geometries to be achieved through sequential operations rather than requiring a single complex molding step.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The salt-leaching step is performed as a preliminary action before foam formation. By removing salt particles first, a porous template is created that guides subsequent foam infiltration, enabling complex shapes to form naturally through the template rather than requiring complex molds.

Inventive Principle:

Principle #10Preliminary action

2Manufacturing precision

If salt-leaching and solvent casting techniques are combined, then controlled porosity and customized shapes are achieved, but manufacturing complexity increases

Engineering Contradiction:

Improveporosity controlVSAvoidprocess steps

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

Porosity is controlled by changing parameters including salt particle size distribution, salt concentration in the initial mixture, and solvent properties. These parameter adjustments enable precise porosity control without adding complex process steps, as the same salt-leaching and solvent casting sequence handles all porosity requirements.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

Salt particles serve as an intermediary template that temporarily occupies space during manufacturing. The salt is leached away to create pores, and the solvent acts as an intermediary carrier that delivers polymer material into the porous structure. These intermediaries enable precise porosity control through their physical properties rather than complex process control.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If pre-polymerized polymer pellets are used, then material biocompatibility is improved, but the need for isocyanate-polyol reaction eliminates certain processing options

Engineering Contradiction:

ImprovebiocompatibilityVSAvoidprocessing flexibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The chemical reaction system (isocyanate-polyol) is replaced with a physical process system using pre-polymerized pellets dissolved in solvent. This substitution maintains biocompatibility while enabling the salt-leaching and solvent casting process, as the pellets can be directly incorporated into the porous template without requiring reactive chemistry.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The polymer material state is changed from reactive liquid (isocyanate-polyol mixture) to pre-polymerized solid pellets. This parameter change enables use of biocompatible materials while adapting the processing method to dissolution and casting rather than chemical reaction, maintaining versatility through solvent selection.

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

This process enables the production of foams with customized shapes at a millimeter scale, controlled porosity, and integration of additional materials, making them suitable for biocompatible applications such as endovascular prostheses.

Implementation Method 1

dissolving a polymer material in a solvent to form a polymer solution

Methodology Applied

Scientific EffectDissolution: Solvation

Implementation Method 2

the solid particulate is insoluble in the polymer solution and soluble in the washing liquid, and wherein after washing the polymer mixture with the washing liquid, the remaining polymer material in the mold forms the foam

Methodology Applied

Scientific EffectDissolution: Solvation