Polymer Powder Electrostatic Deposition for Microstructure Replication

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Solution Overview

Problem

Current microfabrication techniques face challenges in achieving high precision and speed while using a wide range of materials, particularly in replicating complex microstructures and nanostructures, and often require high temperatures and costly metal molds.

Innovation Solution

A process involving electrostatic powder coating of polymers onto molds, which allows for the creation of polymeric films with microstructured or nanostructured patterns, using thermoplastic or thermoset polymers, and UV curable powders that cure at lower temperatures, enabling faster and more cost-effective production of microstructured products.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional liquid polymer techniques are used for microfabrication, then the process is simple, but air entrapment occurs and manufacturing precision deteriorates

Engineering Contradiction:

Improveprocess simplicityVSAvoidmicrostructure precision

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention changes the physical state of the polymer from liquid to powder form. This parameter change eliminates air entrapment issues inherent in liquid polymer techniques while maintaining processability through electrostatic deposition and thermal melting, thereby achieving both ease of manufacture and high manufacturing precision

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention replaces traditional mechanical injection or casting methods with electrostatic deposition. The charged polymer powder is attracted to and deposited on the mold surface, then melted and cured to form precise microstructures. This substitution eliminates air entrapment while maintaining process simplicity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If metal molds are used for microfabrication, then manufacturing precision is maintained, but fabrication cost and device complexity increase

Engineering Contradiction:

Improvemicrostructure precisionVSAvoidfabrication cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The invention employs disposable or reusable polymeric molds instead of expensive metal molds. These polymeric molds can be fabricated using rapid prototyping techniques, significantly reducing fabrication cost and device complexity while maintaining sufficient manufacturing precision for microstructured products

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The invention creates precise microstructures by depositing polymer powder onto polymeric mold surfaces that contain the inverse pattern. The powder is melted and cured to form accurate replicas of the mold surface features, achieving high manufacturing precision without requiring expensive metal mold tooling

Inventive Principle:

Principle #26Copying

3Adaptability or versatility

If high temperature curing is used for polymer powder, then material selection is limited, but manufacturing speed and productivity decrease

Engineering Contradiction:

Improvematerial selection rangeVSAvoidmanufacturing speed

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The invention changes the curing mechanism from thermal to photochemical by using UV-curable polymer powders. This parameter change allows curing at room temperature or low temperatures, dramatically increasing manufacturing speed and productivity while expanding material selection to include temperature-sensitive polymers and composites

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention replaces thermal curing with UV photopolymerization. The UV-curable powder is deposited on the mold, then irradiated with UV light to initiate rapid curing. This substitution eliminates the need for high temperature heating, increasing manufacturing speed and enabling use of temperature-sensitive materials

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 method enables the rapid and economical production of microstructured products with improved mechanical, electrical, and optical properties, using a variety of materials, including those with high service temperatures, and allows for the creation of precision microstructures and nanostructures without the limitations of air entrapment and viscosity issues in traditional techniques.

Implementation Method 1

polymer powder is applied in a conventional electrostatic powder coating process

Methodology Applied

Scientific EffectElectrostatic deposition: Electrostatic Deposition

Implementation Method 2

the powder is melted

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 3

If the mold and powder are made from a UV curable thermoset, then the powder is cured by UV irradiation

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentUS8226880B2Process for fabricating precise microstructures

Publication Date: 2012.07.24 THE BOEING CO

AI summary

There is disclosed a method and apparatus for producing a polymeric film that accurately replicates a mold surface at least a portion of which surface has a complex pattern of microstructured or nano-structured dimensions. A polymeric powder is electrodeposited on an underlying mold surface and heated to its molten state to replicate a pattern on the mold surface. Then the powder can be cured to create a polymeric film. Finally the film is removed from the mold surface.