Layered Fiber-Reinforced Component for Laser Depth-Controlled Recesses

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Solution Overview

Problem

Forming precise indentations in fiber-reinforced plastic components is challenging due to the inhomogeneous structure and different absorption rates of plastic and fiber materials, leading to difficulties in maintaining dimensional accuracy and quality during material removal, especially with mechanical methods like milling or grinding, and laser radiation.

Innovation Solution

A layered structure is employed where at least one layer has higher reflectivity or transparency to the laser beam than the layer to be removed, allowing for controlled material ablation up to a predetermined depth, with optional additional layers for graded absorption and reduced pigment content, enabling precise formation of depressions with varying depths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If mechanical material removal methods like milling or grinding are used, then material can be removed from the component surface, but edges or margins are formed that exhibit plastic breakouts or protruding fiber ends, requiring extensive manual post-processing and causing high tool wear

Engineering Contradiction:
Improveease of material removalVSAvoiddimensional accuracy of recess
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent replaces mechanical material removal methods (milling, grinding) with laser radiation for material removal. The laser beam ablates material through thermal energy rather than mechanical contact, eliminating tool wear and the formation of plastic breakouts or protruding fiber ends that characterize mechanical processing.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes the different absorption rates of plastic and fiber materials to laser radiation as a key parameter. By selecting appropriate laser wavelengths and controlling exposure, the process selectively removes plastic while preserving fibers, achieving dimensional accuracy without the defects associated with mechanical methods.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If laser radiation is used for material removal, then material can be removed without mechanical contact, but uneven material removal from both plastic and fiber materials leads to difficulties in creating dimensionally accurate recesses, especially when maintaining a predetermined depth

Engineering Contradiction:
Improvequality of material removalVSAvoiddimensional accuracy of recess
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies local quality by creating recesses with different depths in different areas of the component. By controlling laser exposure parameters locally, the process achieves uniform ablation depth across the treatment area while accommodating the need for varying recess depths in different zones of the component.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs periodic action through pulsed laser radiation. By using periodic laser pulses rather than continuous irradiation, the process allows heat dissipation between pulses, preventing excessive thermal accumulation that could cause uneven material removal or damage to the fiber-reinforced structure.

Inventive Principle:
Principle #19Periodic action

3Manufacturing precision

If a layer with higher reflectivity is introduced to control laser absorption, then material removal can be controlled to predetermined depth, but the component structure becomes more complex with additional layers

Engineering Contradiction:
Improvedepth control of recessVSAvoidcomplexity of layered structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by incorporating layers with different reflectivity characteristics into the component structure before the laser treatment step. This pre-positioning of optical property variations allows the subsequent laser process to automatically achieve the desired material removal depth without requiring real-time depth control adjustments.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses local quality by placing layers with specific reflectivity properties at particular locations within the component structure. These strategically positioned layers serve as depth control markers for the laser process, enabling precise material removal only where needed while maintaining the integrity of other component areas.

Inventive Principle:
Principle #3Local quality

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 allows for the formation of dimensionally accurate and reproducible indentations with reduced tool wear and complex post-processing, maintaining specified dimensions and enabling precise insertion of components like sensors or actuators without affecting the component's properties.

Implementation Method 1

material removal to a predetermined depth from a surface of the component is to be carried out using a laser beam

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

The material of the further layer has a reflectivity of the laser beam used for material removal with at least one wavelength that is at least 5% greater, preferably at least 7% greater, than the reflectivity of the at least one layer formed with fiber-reinforced plastic

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3645286B1Component made up of several stacked layers, as well as a process for its manufacture
Publication Date: 2022.05.11 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP3645286B1 patent drawingFigure 1
  • EP3645286B1 patent drawingFigure 2

AI summary

The invention relates to a component (6) which is formed with a plurality of layers (1.1,..., 1.5) arranged one over the other. Material should be removed by means of a laser beam in order to form a recess on the surface of the component having a specified depth from a surface of the component. At least one of the layers (1.1,..., 1.5) is formed from a fiber-reinforced plastic material. Within the component, a further layer (2) is arranged at a depth in such a way that the surface is arranged at the plane down to which material should be removed. The material of the further layer (2) has a reflectivity of the laser beam used for material removal that is at least 5% greater than the reflectivity of the at least one layer (1.1,..., 1.5) formed with fiber-reinforced plastic. After irradiation with a laser beam in a region of the surface, material is removed down to the surface of the further layer (2) facing the incident laser beam in order to form a recess. The invention further relates to a method for producing the component (6).