Coating Edge Thickness Control Using Air Knife Pneumatics

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Achieving a well-defined, uniformly thick coating with a clean edge is difficult due to surface tension driven flow and edge evaporation effects, leading to a thicker 'beading edge' that interferes with adhesion, aesthetics, and functionality in coated products like roofing membranes and asphalt shingles.

Innovation Solution

A method involving the application of a coating to a moving substrate, where the thickness of a portion of the coating along an edge is modified by relocating or removing coating material using non-mechanical forces, such as air knives directing fluid or applying pressure, to create a substantially predetermined profile, preventing the formation of a beading edge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If coating is applied to a moving substrate using conventional methods, then coating coverage is achieved, but surface tension driven flow and edge evaporation effects cause thicker beading edge formation

Engineering Contradiction:

Improvecoating coverageVSAvoidedge thickness uniformity

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent applies a preliminary action by using air knives to modify the coating material at the edge before the coating is fully deposited. The air knives create a controlled flow that prevents surface tension driven beading from occurring in the first place, rather than attempting to correct the beading after it forms. This preliminary intervention ensures uniform edge thickness while maintaining overall coating coverage.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent employs pneumatic principles by using air knives that direct controlled streams of air at the coating material at the substrate edge. This pneumatic flow modifies the coating material's behavior, counteracting surface tension effects and preventing beading edge formation. The air knives create a hydraulic-like flow pattern that redistributes the coating material uniformly at the edge region.

Inventive Principle:

Principle #29Pneumatics and hydraulics

2Quantity of substance

If coating material accumulates at the edge, then complete coverage is maintained, but adhesion and aesthetics are compromised

Engineering Contradiction:

Improvecoating completenessVSAvoidadhesion quality

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The air knives perform a preliminary action by modifying the coating flow at the edge before adhesion issues can develop. By preventing beading edge formation in advance, the coating maintains uniform thickness that ensures proper adhesion to the substrate. The preliminary pneumatic intervention eliminates the root cause of adhesion problems rather than addressing them after they occur.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces mechanical coating control mechanisms with a pneumatic field-based approach. Instead of using mechanical scrapers or knives that physically contact the coating, the invention uses air knives that create a pneumatic field to control coating flow. This non-contact method prevents mechanical damage while ensuring uniform edge thickness and proper adhesion.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If conventional coating application is used, then productivity is maintained, but beading edge formation requires additional corrective processes

Engineering Contradiction:

Improvecoating application rateVSAvoidprocess complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent uses pneumatic principles to simplify the overall process by preventing beading edge formation at the source. The air knives integrate seamlessly into the existing coating line, maintaining high productivity while eliminating the need for separate corrective processes. This pneumatic approach adds minimal complexity compared to mechanical correction systems while significantly improving edge uniformity.

Inventive Principle:

Principle #29Pneumatics and hydraulics

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

The method ensures a uniform coating thickness and edge profile, enhancing adhesion, aesthetics, and functionality by preventing the accumulation of contaminants and improving the sealing process in coated products.

Implementation Method 1

air knives directing fluid or applying pressure

Methodology Applied

Scientific EffectFluid flow:

Implementation Method 2

surface tension driven flow

Methodology Applied

Scientific EffectSurface tension: Surface Tension

Implementation Method 3

edge evaporation effects

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentUS7867562B2Method of controlling coating edge thickness in a web process

Publication Date: 2011.01.11 CERTAINTEED CORP

AI summary

One method for controlling edge thickness includes applying a coating to a moving substrate, thereby forming a film having a cross direction and a machine direction and one or more edges. The method also includes modifying a thickness of a first portion of the coating along one of the edges of the film, thereby forming a film having a substantially predetermined profile in the cross direction. A method of making a polymeric sheet includes applying a polymer to a moving substrate, thereby forming a sheet having a cross direction and a machine direction. This method further includes removing a first portion of the polymer from a first edge of the sheet, thereby the sheet having a substantially predetermined profile in the cross direction.