Narrowband Infrared Curing for Aluminum Can Strength

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Solution Overview

Problem

Conventional inside bake ovens (IBOs) used in can manufacturing are energy-intensive, lead to aluminum weakening due to de-tempering/annealing effects, and require extensive maintenance, while also being inefficient and environmentally unsustainable.

Innovation Solution

A method utilizing narrowband, semiconductor-based radiant infrared energy for high-speed curing of can coatings, reducing curing time to less than 20 seconds to prevent annealing and weakening of aluminum, and implementing a system with reconfigured tooling to use thinner coil stock, thereby reducing aluminum usage and energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If conventional inside bake ovens are used for curing can coatings, then the coating curing function is achieved, but energy consumption increases and aluminum can strength decreases due to de-tempering/annealing effects

Engineering Contradiction:

Improveenergy consumptionVSAvoidaluminum can strength

Core Design Contradiction:

Use of energy by moving objectVSStrength

Solution Approach 1:

The patent replaces the conventional thermal convection curing system with a radiant heating system that uses infrared or electromagnetic radiation to cure the coating. This substitution allows for rapid, localized heating of the coating without significantly heating the aluminum can body, thereby maintaining can strength while reducing overall energy consumption. The radiant energy is directly absorbed by the coating material, enabling curing in a fraction of the time required by conventional ovens.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the curing process parameters by using high-intensity radiant heating that delivers concentrated energy to the coating surface. This results in a dramatic reduction of curing time from minutes to seconds, preventing the aluminum can from undergoing de-tempering or annealing that would weaken it. The rapid parameter change in heating rate and duration allows coating cure without compromising the metallurgical properties of the aluminum.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If conventional inside bake ovens are used for curing can coatings, then the coating curing function is achieved, but the system complexity and maintenance requirements increase

Engineering Contradiction:

Improvecuring process reliabilityVSAvoidoven system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the curing function from the complex conventional oven system and implements it as a standalone radiant heating module. This extracted curing mechanism uses simple radiant panels or lamps that directly emit infrared or electromagnetic energy onto the coating, eliminating the need for complex convection fans, temperature distribution systems, and long-duration thermal management infrastructure. The result is a simpler, more reliable system with fewer moving parts and maintenance requirements.

Inventive Principle:

Principle #2Taking out (Extraction)

3Strength

If thicker coil stock aluminum is used to maintain can strength, then can strength is improved, but aluminum usage and weight increase

Engineering Contradiction:

Improvecan strengthVSAvoidcan weight

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The patent applies preliminary action by curing the coating so rapidly using radiant heating that the aluminum can never reaches temperatures that would cause de-tempering or annealing. This preliminary, ultra-fast curing action prevents the weakening effect before it can occur, allowing the use of thinner aluminum stock without compromising final can strength. The timing of the curing action is critical - it must complete before thermal damage to the aluminum microstructure can begin.

Inventive Principle:

Principle #10Preliminary action

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 approach significantly reduces aluminum usage, maintains strength comparable to thicker cans, and achieves substantial energy savings, while eliminating the need for over-strengthening cans and minimizing environmental impact.

Implementation Method 1

narrowband, semiconductor-based radiant infrared energy for high-speed curing of can coatings

Methodology Applied

Scientific EffectRadiant infrared energy: Infrared Radiation

Implementation Method 2

brought to a critical temperature to start a curing linking process

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentUS20230311158A1System and method for inside of can curing

Publication Date: 2023.10.05 PHOTEX INC

AI summary

An improved inside of can curing technology is provided. One implementation uses narrowband, semiconductor produced infrared energy which is focused into the inside of the can to affect a very high-speed curing result and will directly impact the coating covering the inside walls of the can to rapidly cure the coating. Detempering and annealing of the aluminum can body does not have time to occur, thus leaving a stronger can with the same amount of aluminum or a can of the same strength but with less aluminum. It is also possible to eliminate the natural gas fueled oven that is the current standard and replace it with a completely hydrocarbon-free curing alternative that has superior performance. This high powered radiant, narrowband energy will be digitally controlled to introduce only the needed heat and to not overheat the can.