Hard-Coated Embossing Roller Structuring With Low-Roughness Features

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Solution Overview

Problem

Existing embossing devices, such as rollers and drums, often have high surface roughness on their inner surfaces, leading to abrasion and undesirable optical effects in embossed films and foils, which reduce their optical quality and durability.

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 form structural features and subsequent polishing to smooth the interior surfaces, achieving a surface roughness below 60 nm and enhancing the durability and optical quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If laser ablation is used to form structural features on hard-coated embossing rollers, then manufacturing precision and structural complexity are improved, but surface roughness increases leading to abrasion and optical defects

Engineering Contradiction:

Improvestructural feature precisionVSAvoidsurface roughness and abrasion

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The manufacturing process is segmented into two distinct stages: first, laser ablation creates the structural features with high precision; second, a separate polishing process smooths the surfaces. This segmentation allows each process to optimize for its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The polishing process is applied as a preliminary finishing step after laser ablation. By preparing the surface in advance through polishing, the harmful surface roughness is eliminated before the embossing device is put into service, preventing abrasion and optical defects.

Inventive Principle:

Principle #10Preliminary action

2Illumination intensity

If hard-coating layer thickness is reduced to less than 30 μm, then optical quality is improved, but durability and abrasion resistance deteriorate

Engineering Contradiction:

Improveoptical qualityVSAvoiddurability and abrasion resistance

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The polishing process applies local quality improvement by selectively smoothing only the interior surfaces of the structural features while preserving the overall hard-coating layer integrity. This localized treatment enhances optical quality in critical areas without compromising the protective function of the hard coating.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The embossing roller employs a composite structure with a hard-coating layer providing durability and a polished surface layer providing optical quality. The combination of these two layers with different properties resolves the contradiction between thickness reduction for optics and maintenance of durability.

Inventive Principle:

Principle #40Composite materials

3Manufacturing precision

If polishing is applied to smooth interior surfaces of structural features, then surface finish and optical quality are improved, but manufacturing time and process complexity increase

Engineering Contradiction:

Improvesurface smoothnessVSAvoidmanufacturing cycle time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The polishing process is integrated into the manufacturing workflow as a continuous operation following laser ablation. By maintaining continuous useful action without unnecessary interruptions or repositioning, the polishing step efficiently removes surface irregularities while minimizing additional manufacturing time.

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 results in embossing devices with improved surface smoothness and durability, reducing abrasion and enhancing the optical quality of embossed materials, while allowing for the creation of complex 3D structures with precise dimensions and patterns.

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

PatentUS20240017458A1Method and system for manufacturing an embossing device and corresponding embossing device

Publication Date: 2024.01.18 BOEGLI GRAVURES SA

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.