Screen Printed Shaped Abrasive Particles via Differential Pressure Transfer

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Solution Overview

Problem

Existing abrasive particles and articles face limitations in cost, performance, and lifespan, particularly in manufacturing processes where triangular-shaped particles are used, as they often result in suboptimal cut rates and surface finish due to their random crushing methods.

Innovation Solution

The production of shaped abrasive particles using a screen printing technique with an alpha alumina precursor, employing differential pressure to assist in transferring the dispersion from the printing screen, allowing for thicker particles and improved grinding performance by creating particles with a tapered shape due to sol gel viscosity and drying processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If random crushing method is used to produce abrasive particles, then production cost is reduced, but cutting performance and surface finish deteriorate

Engineering Contradiction:
Improveproduction costVSAvoidcutting performance
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent changes the shape parameter of abrasive particles from random (crushed) to controlled geometric shapes (triangular, rectangular, circular) through screen printing. This allows optimization of cutting performance while maintaining cost-effectiveness by using a scalable manufacturing process.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies different shapes to different abrasive particles in the mixture, creating local quality variations. Triangular particles provide cutting action, while rounded particles provide finishing action, optimizing overall performance without requiring all particles to be uniformly complex shapes.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If screen printing technique is used to produce shaped abrasive particles, then cutting performance is improved, but productivity decreases

Engineering Contradiction:
Improvecutting performanceVSAvoidproduction rate
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent uses screen printing to pre-form the abrasive particles into desired shapes before they are applied to the workpiece. This preliminary shaping action ensures optimal cutting performance from the start, eliminating the need for subsequent reshaping or selection processes.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent employs a continuous screen printing process where the screen is repeatedly dipped into the abrasive slurry and pressed against the substrate, allowing continuous production of shaped abrasive particles without interruption or batch processing delays.

Inventive Principle:
Principle #20Continuity of useful action

3Duration of action of stationary object

If thick shaped abrasive particles are produced, then lifespan is extended, but removal from screen openings becomes difficult

Engineering Contradiction:
ImprovelifespanVSAvoidremoval difficulty
Core Design Contradiction:
Duration of action of stationary objectVSEase of manufacture

Solution Approach 1:

The patent employs vibration or ultrasonic assistance during the screen printing process to facilitate the removal of thick abrasive particle formations from the screen openings. The vibration energy helps break the adhesion between the thick particle layer and the screen, enabling easy removal while maintaining particle integrity.

Inventive Principle:
Principle #18Mechanical vibration

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 enhances grinding performance by producing particles with thinner edges and acute angles, leading to improved cutting efficiency and surface finish, as demonstrated by the comparison of high and low viscosity sol gels in grinding tests.

Implementation Method 1

a sol gel dispersion having a lower viscosity that creeps or flows under its own weight after the formation process

Methodology Applied
Scientific EffectViscosity:

Implementation Method 2

applying a differential pressure between a first side of the screen printed shape and a second side of the screen printed shape that is in contact with a receiving surface

Methodology Applied
Scientific EffectDifferential pressure: Pressure Gradient

Implementation Method 3

a pressurized transfer roll can apply a positive pressure to the first side to release the screen printed shapes from the printing screen

Methodology Applied
Scientific EffectPressure: Pressure Increase

Implementation Method 4

a vacuum box or a vacuum roll can be located to provide a pressure less than atmospheric pressure to the second side of the screen printed shapes

Methodology Applied
Scientific EffectVacuum: Vacuum

Implementation Method 5

at least partially drying the dispersion to form precursor shaped abrasive particles

Methodology Applied
Scientific EffectDrying: Evaporation

Implementation Method 6

firing the precursor shaped abrasive particles to final sintered hardness forming shaped abrasive particles comprising alpha alumina

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentEP3943243B1Transfer assisted screen printing method of making shaped abrasive particles and the resulting shaped abrasive particles
Publication Date: 2024.09.25 3M INNOVATIVE PROPERTIES CO
  • EP3943243B1 patent drawingFigure 1
  • EP3943243B1 patent drawingFigure 2~3A
  • EP3943243B1 patent drawingFigure 3B~3C

AI summary

The present invention relates to a shaped abrasive particles comprising a first side 38, a second side 40, and a sidewall 54 connecting the first side 38 to the second side 40, the particles comprising a generally triangular shape; the sidewall 54 comprising a first portion 56 intersecting the first side 38 and a second portion 58 intersecting the second side 40, wherein the slope of the first portion 56 is greater than the slope of the second portion 58.