Horizontal Electrostatic Abrasive Coating for Heavy Particles

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Solution Overview

Problem

Conventional electrostatic systems for applying abrasive particles to coated backings face challenges with heavy particles, requiring additional coatings and humidification, and struggle to achieve uniform orientation and patterned applications, especially in low humidity environments.

Innovation Solution

A new electrostatic coating process where abrasive particles are propelled horizontally onto the backing using a vibratory feeder connected to a voltage potential, allowing for varied z-direction rotational orientation and patterned applications without supplemental humidification, enabling the application of heavier particles and eliminating the need for expensive coatings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If conventional electrostatic systems apply abrasive particles vertically against gravity, then lighter particles can be applied with simple equipment, but heavier particles cannot be applied effectively and require additional coatings or drop coating methods

Engineering Contradiction:
Improveabrasive particle weightVSAvoidequipment complexity
Core Design Contradiction:
Weight of moving objectVSDevice complexity

Solution Approach 1:

The patent inverts the conventional vertical application method by applying abrasive particles in a horizontal direction parallel to the backing surface. The feeding tray moves horizontally through the electrostatic field, allowing particles to be propelled onto the backing without fighting gravity, enabling application of heavier particles up to ANSI 20 grit and beyond

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent replaces the mechanical gravity-overcoming vertical lift with an electrostatic horizontal propulsion system. The electrostatic field propels particles horizontally from the feeding tray to the backing, eliminating the need for complex mechanical systems to overcome gravitational force for heavy particles

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Weight of moving object

If conventional systems use heavy abrasive particles, then electrostatic attraction is insufficient, but adding expensive coatings to enhance attraction reduces manufacturing cost efficiency

Engineering Contradiction:
Improveabrasive particle weightVSAvoidmanufacturing cost
Core Design Contradiction:
Weight of moving objectVSEase of manufacture

Solution Approach 1:

The patent extracts and eliminates the need for expensive electrostatic enhancement coatings by using the horizontal application method. The electrostatic field alone is sufficient to propel and attach heavy particles when applied horizontally, removing the requirement for additional costly coating materials

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the application parameter from vertical to horizontal direction, which fundamentally alters the electrostatic field's effectiveness. This parameter change allows the electrostatic field to efficiently propel heavy particles without requiring enhanced coatings, maintaining cost-effectiveness

Inventive Principle:
Principle #35Parameter changes

3Reliability

If conventional systems operate in low humidity environments, then electrostatic field performance degrades, but adding humidification equipment increases device complexity and cost

Engineering Contradiction:
Improveelectrostatic field performanceVSAvoidhumidification equipment
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent converts the potential harm of low humidity (which can cause static discharge and field instability) into a benefit by using the horizontal application method. The horizontal propulsion through the electrostatic field is less sensitive to humidity variations, allowing reliable operation in low humidity environments without humidification equipment

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

4Stability of the object's composition

If conventional systems apply particles vertically, then particle orientation is random, but achieving uniform elongated orientation requires complex field configurations

Engineering Contradiction:
Improveparticle orientation uniformityVSAvoidelectrostatic field configuration
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent inverts the application direction from vertical to horizontal, which naturally aligns particles with their elongated dimension parallel to the backing surface during horizontal propulsion. This simplified field configuration achieves uniform elongated orientation without complex multi-component field arrangements

Inventive Principle:
Principle #13The other way round (Inversion)

5Productivity

If conventional systems use heavy particles requiring drop coating, then application speed decreases, but electrostatic application of heavy particles is not feasible

Engineering Contradiction:
Improvecoating application speedVSAvoidabrasive particle weight
Core Design Contradiction:
ProductivityVSWeight of moving object

Solution Approach 1:

The patent replaces the slow mechanical drop coating process with rapid electrostatic horizontal propulsion. The electrostatic field rapidly accelerates heavy particles horizontally onto the backing, achieving high-speed coating application that is impossible with conventional vertical electrostatic or drop coating methods

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 achieves uniform elongated orientation of abrasive particles, allows for the application of heavier particles, and enables patterned coatings, improving the abrasive action and finish of the coated article while operating effectively in low humidity environments.

Implementation Method 1

the abrasive particles are moved by a vibratory feeder having a feeding tray

Methodology Applied
Scientific EffectVibration: Vibration

Implementation Method 2

the abrasive particles are moved by a vibratory feeder having a feeding tray with at least a portion of the feeding tray connected to a voltage potential generating an electrostatic field

Methodology Applied
Scientific EffectElectrostatic field: Electric Field

Implementation Method 3

translating the particles along the feeding surface and propelling the particles substantially horizontally across a gap to the backing and attaching the particles to the make layer by an electrostatic force

Methodology Applied
Scientific EffectElectrostatic force: Electrostatics

Data Source

PatentEP2675575B1Electrostatic abrasive particle coating apparatus and method
Publication Date: 2021.11.03 3M INNOVATIVE PROPERTIES CO
  • EP2675575B1 patent drawingFigure 1
  • EP2675575B1 patent drawingFigure 2
  • EP2675575B1 patent drawingFigure 3A~3C

AI summary

A method of applying particles to a backing having a make layer on one of the backing's opposed major surfaces. The method including the steps of: supporting the particles on a feeding member having a feeding surface such that the particles settle into one or more layers on the feeding surface; the feeding surface and the backing being arranged in a non-parallel manner; and translating the particles from the feeding surface to the backing and attaching the particles to the make layer by an electrostatic force.