Coating Substrate Droplet Impact Angle Control

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Solution Overview

Problem

Conventional coating methods for medical implants, such as stents, result in inhomogeneous coating thickness, cracks, and difficulty in producing porous coatings, which are necessary for therapeutic agent delivery and tissue ingrowth, and do not allow for instantaneous adjustment of coating morphology to accommodate varying medical application needs.

Innovation Solution

A method involving the generation of droplets with a tangential velocity component and controlled impact angle less than 80 degrees, allowing for variable porosity and surface area, and adjustable swirl intensity during the coating process to achieve desired surface morphology and properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If spray coating is applied with droplets impacting at approximately 90 degrees, then coating compaction is achieved, but coating thickness becomes inhomogeneous and cracks form

Engineering Contradiction:

Improvecoating compactionVSAvoidcoating thickness uniformity

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The invention changes the impact angle parameter from the conventional 90 degrees to between 10 and 80 degrees. This parameter modification allows the coating to achieve adequate compaction while reducing the impulse force that causes inhomogeneous thickness and cracking, thereby resolving the technical contradiction between coating strength and manufacturing precision.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If conventional spray coating methods are used, then coating application is achieved, but porous coatings cannot be produced

Engineering Contradiction:

Improvecoating applicationVSAvoidporosity control

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The invention modifies the droplet impact angle parameter to between 10 and 80 degrees, which reduces coating compaction and enables the formation of porous structures. This parameter change provides versatility in producing both dense and porous coatings depending on the specific application requirements, while maintaining ease of manufacture through the same spray coating process.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If conventional coating methods are used, then coating is applied to substrate, but coating morphology cannot be adjusted instantaneously

Engineering Contradiction:

Improvecoating application rateVSAvoidcoating morphology adjustment

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The invention introduces dynamic control of the droplet impact angle during the coating process. By making the impact angle adjustable and variable during coating application, the system can instantaneously modify coating morphology to accommodate different therapeutic requirements, thereby achieving both high productivity and adaptability.

Inventive Principle:

Principle #15Dynamics

4Productivity

If high impact angle spray coating is used, then coating deposition is efficient, but surface area and porosity are reduced

Engineering Contradiction:

Improvecoating deposition efficiencyVSAvoidcoating surface area

Core Design Contradiction:

ProductivityVSArea of stationary object

Solution Approach 1:

The invention changes the impact angle parameter from high (90 degrees) to between 10 and 80 degrees. This modification reduces the compaction effect, allowing the coating to retain greater surface area and porosity while maintaining adequate deposition efficiency through optimized spray parameters and geometry.

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 method enables the production of coatings with controlled porosity and surface area, minimizing compaction and enhancing biocompatibility, allowing for immediate adjustment of coating properties to meet specific therapeutic agent delivery requirements.

Implementation Method 1

An atomizing device including an orifice and an internal fluid passage leading to said orifice is typically placed perpendicular to the longitudinal axis of the substrate to be coated. The droplets generated by the atomizing device are expelled through the orifice

Methodology Applied

Scientific EffectAtomization:

Implementation Method 2

generating droplets from a coating composition, transporting the droplets to the substrate

Methodology Applied

Scientific EffectSurface tension: Surface Tension

Data Source

PatentUS7892593B2Process for coating a substrate

Publication Date: 2011.02.22 IOOS LLC

AI summary

A method to coat a substrate for the formation of coatings having a desired surface morphology is provided, wherein the roughness and the total surface area of the coating can be varied during the coating process. The method of the present invention comprises the steps of generating droplets from a coating composition, transporting the droplets to the substrate and depositing a majority of the droplets on the substrate.