Laser Diode Array Heating for Thermoplastic Reinforcement

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Solution Overview

Problem

Existing methods for producing reinforcement structures on molded bodies, such as pressure vessels, are costly and inefficient due to the use of imaging optics, which increase complexity and unit costs, and result in unstable connections between the molded body and the reinforcement structure.

Innovation Solution

A device using a laser diode array with surface emitters to directly irradiate a fiber-reinforced thermoplastic band, eliminating the need for imaging optics and allowing for a more stable and cost-effective reinforcement structure application by ensuring a uniform temperature distribution across the band's thickness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If imaging optics are used to focus laser light on the plastic strip and substrate, then the required heating intensity can be achieved, but the device complexity and cost increase significantly

Engineering Contradiction:
Improveheating intensityVSAvoiddevice complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent removes the imaging optics from the laser heating system, extracting the problematic component that caused complexity and cost issues. Instead of using laser diodes with imaging optics, the invention employs black body radiators that generate thermal radiation directly without requiring optical focusing elements, thereby eliminating the complexity while maintaining effective heating intensity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/optical system (laser diodes with imaging optics) with a thermal radiation system (black body radiators). This substitution eliminates the need for complex optical components while achieving the same heating effect through thermal radiation, thus reducing device complexity without compromising heating intensity.

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

2Temperature

If imaging optics are used to focus laser light, then heating intensity is sufficient, but the optics become soiled during operation requiring cleaning pauses that reduce productivity

Engineering Contradiction:
Improveheating intensityVSAvoidproductivity
Core Design Contradiction:
TemperatureVSProductivity

Solution Approach 1:

The patent removes the imaging optics that were prone to contamination, eliminating the root cause of productivity losses. By using black body radiators instead of optical systems, there are no lenses or mirrors to soil during operation, thus preventing cleaning pauses and maintaining continuous production.

Inventive Principle:
Principle #2Taking out (Extraction)

3Device complexity

If edge emitter laser diodes are used, then the device structure is simpler, but the beam divergence is high causing rapid intensity loss with distance

Engineering Contradiction:
Improvedevice structureVSAvoidheating intensity
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The patent replaces edge emitter laser diodes with black body radiators, substituting an optical system with a thermal radiation system. This replacement maintains structural simplicity while eliminating beam divergence issues, as thermal radiation naturally distributes heat effectively without the intensity loss characteristic of divergent laser beams.

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

4Reliability

If the plastic strip is heated to enable bonding, then connection to the substrate is achieved, but thermal stresses may cause instability

Engineering Contradiction:
Improveconnection stabilityVSAvoidstructural stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent changes the heating method from localized laser heating to distributed thermal radiation heating. This parameter change in the heating approach allows for more uniform temperature distribution across the bonding surfaces, reducing thermal gradients and minimizing thermal stresses that would otherwise compromise structural stability, while still achieving reliable bonding.

Inventive Principle:
Principle #35Parameter changes

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 solution provides a stable and cost-effective reinforcement structure with reduced thermal stresses and increased stability of the molded body, enabling it to withstand high pressures without the need for complex and expensive imaging optics.

Implementation Method 1

a laser diode array with surface emitters to directly irradiate a fiber-reinforced thermoplastic band

Methodology Applied
Scientific EffectLaser radiation heating: Laser

Implementation Method 2

The band can be heated in this way both on the front side and on the back side

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 3

A reliable and stable connection between the shaped body and the support structure is necessary here

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 4

ensuring a uniform temperature distribution across the band's thickness

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3221122B1Device and method for producing a reinforcing structure on the surface of a moulding
Publication Date: 2018.12.12 KAUTEX TEXTRON GMBH & CO KG
  • EP3221122B1 patent drawingFigure 1~2
  • EP3221122B1 patent drawingFigure 3~4
  • EP3221122B1 patent drawingFigure 5

AI summary

The present invention discloses a device for producing a reinforcing structure, which comprises a strip that is fiber-reinforced and comprises thermoplastic material, on the surface of a molding. The device is characterized in that it is designed such that the laser diode array directly irradiates the heating-up area of the strip and/or the heating-up area of the surface of the molding or of the already formed reinforcing structure, wherein the laser diodes of the laser diode array are formed as surface emitters.