Hard-Coated Embossing Roller Laser Structuring With Low Roughness

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Solution Overview

Problem

Existing embossing devices, such as rollers and drums, often suffer from high surface roughness within embossing structures, leading to increased abrasion and undesirable optical effects in embossed films and foils.

Innovation Solution

A method involving a hard-coated embossing roller with a cylindrically-shaped core and a hard-coating layer, where laser ablation is used to remove material from the hard-coating layer to form structural features, followed by polishing to smoothen interior surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If laser ablation is used to form embossing structures on hard-coated rollers, then structural precision and durability are improved, but surface roughness increases leading to harmful optical effects

Engineering Contradiction:

Improveembossing structure precisionVSAvoidsurface roughness

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent segments the manufacturing process into two distinct stages: first, laser ablation creates the embossing structures with high precision; second, a separate polishing step smooths the interior surfaces. This segmentation allows each process to optimize for its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent converts the harmful effect of laser-induced surface roughness into a beneficial process by intentionally polishing the interior surfaces afterward. The roughness created by laser ablation is not merely tolerated but actively removed through controlled polishing, transforming a defect into an opportunity for enhanced surface quality.

Inventive Principle:

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

2Object-generated harmful factors

If hard-coating layer thickness is reduced to less than 30 μm, then optical quality is improved, but structural integrity may be compromised

Engineering Contradiction:

Improveoptical qualityVSAvoidstructural integrity

Core Design Contradiction:

Object-generated harmful factorsVSStrength

Solution Approach 1:

The patent changes the thickness parameter of the hard-coating layer to a specific range (less than 30 μm, preferably 5-20 μm) that optimizes optical quality while maintaining structural integrity. This parameter optimization is achieved through controlled laser ablation that precisely removes material to the desired depth without compromising the underlying structure.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces traditional mechanical machining methods with laser ablation technology. This substitution enables more precise control over material removal, allowing for thinner coating layers to be processed with higher precision and better control over the final surface characteristics, thereby maintaining structural integrity while improving optical quality.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If laser deflection velocity is increased to 100 m/s for high-speed processing, then productivity is improved, but manufacturing precision deteriorates

Engineering Contradiction:

Improveprocessing speedVSAvoidembossing structure precision

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent employs periodic pulsed laser action rather than continuous laser application. By using controlled laser pulses with specific duty cycles, the system achieves high average processing speeds while maintaining precision through the intermittent nature of the energy delivery, allowing heat dissipation and precise material removal control.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent achieves continuous productive action through high-speed laser deflection (up to 100 m/s) combined with rapid pulsing. The useful action of material removal continues effectively at high speeds by maintaining a continuous sequence of controlled pulses, ensuring both productivity and precision are maintained through the continuity of the pulsed process.

Inventive Principle:

Principle #20Continuity of useful 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

The method achieves a significant reduction in surface roughness, improving the durability and optical quality of embossed structures, while maintaining the embossing device's structural integrity.

Implementation Method 1

performing laser ablation to the hard-coated cylinder to remove material from the hard-coating layer to form opening

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Data Source

PatentEP4208335B1A method and system for manufacturing an embossing device and corresponding embossing device

Publication Date: 2025.06.11 BOEGLI GRAVURES SA

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AI summary

A method for manufacturing an embossing device or injection mold including the steps of providing a hard coated embossing roller having a cylindrically-shaped core and a hard-coating layer, the hard-coating layer having a thickness of equal or less than 30 μm, and performing laser ablation to the hard-coated cylinder to remove material from the hard- coating layer to form opening, a surface of the opening forming a structural feature into the hard-coating layer, to form a structured hard-coated cylinder.