Thermoplastic Panel Extrusion Adhesion via Intrinsic Heat

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Solution Overview

Problem

Current methods for producing thermoplastic sandwich panels with a honeycomb structure face challenges in achieving perfect adhesion between layers while maintaining flatness, often requiring multiple complex and wasteful processes, and are not capable of continuous production without external adhesives.

Innovation Solution

A compact plant with continuous extrusion and adhesion phases in a single line, using three extrusion assemblies and cylinders with vacuum assistance to create a three-dimensional central element and two flat covering elements, where the intrinsic heat and pressure of the extruded material ensure adhesion without external adhesives, allowing for simultaneous creation and coupling of all layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If multiple complex processes are used to achieve perfect adhesion and flatness, then manufacturing precision is improved, but device complexity and production time increase

Engineering Contradiction:
Improveadhesion qualityVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple processes (extrusion, forming, adhesion) into a single continuous operation. The first extrusion head produces the central honeycomb layer while the second and third extrusion heads simultaneously produce the flat covering layers, all within one continuous production line without requiring separate processing stages.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention implements continuous production where the panel layers are extruded and bonded in an uninterrupted sequence. The material flows continuously through the extrusion heads and bonding cylinders without stopping, eliminating the need for discrete processing steps and reducing overall production time.

Inventive Principle:
Principle #20Continuity of useful action

2Strength

If external adhesives are used to bond layers, then adhesion strength is improved, but loss of substance and environmental impact increase

Engineering Contradiction:
Improveadhesion strengthVSAvoidadhesive material consumption
Core Design Contradiction:
StrengthVSLoss of substance

Solution Approach 1:

The patent employs self-service bonding where the thermoplastic material itself provides the bonding function. The heating cylinders soften the material at the bonding interfaces, allowing the layers to adhere to each other through the material's intrinsic properties without requiring external adhesives or chemical bonding agents.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention changes the thermal parameters of the bonding cylinders to control the softening of the thermoplastic material. By adjusting the temperature and pressure parameters during the bonding phase, the material achieves optimal adhesion strength through controlled melting and re-solidification, eliminating the need for chemical adhesives.

Inventive Principle:
Principle #35Parameter changes

3Strength

If suction is applied during cooling to create adherence, then adhesion is improved, but surface flatness deteriorates

Engineering Contradiction:
ImproveadhesionVSAvoidsurface flatness
Core Design Contradiction:
StrengthVSShape

Solution Approach 1:

The patent replaces the mechanical suction system with a thermal bonding system. Instead of using suction to press the layers together (which causes surface deformation), the invention uses heated cylinders to soften the thermoplastic material, allowing it to flow and bond naturally while maintaining surface flatness through controlled thermal processing.

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

4Manufacturing precision

If multiple separate plants are used for producing different layers, then manufacturing precision is improved, but productivity and production time worsen

Engineering Contradiction:
Improvelayer qualityVSAvoidproduction speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The invention merges the production of multiple panel layers into a single continuous extrusion process. The first, second, and third extrusion heads work simultaneously in one location, producing the central honeycomb layer and the two flat covering layers in parallel, thereby achieving both high precision and high productivity.

Inventive Principle:
Principle #5Merging (Combining)

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 achieves perfect adhesion and high planarity of the panels, reducing delamination and simplifying the production process, resulting in improved mechanical properties and reduced production time and waste.

Implementation Method 1

said first, second and third strips are made to adhere to the respective cylinders by creating a vacuum

Methodology Applied
Scientific EffectVacuum: Vacuum

Implementation Method 2

the intrinsic heat and pressure of the extruded material ensure adhesion without external adhesives

Methodology Applied
Scientific EffectThermal energy: Heating

Data Source

PatentEP3769930B1Method and plant for the production of three-layer panels in thermoplastic material
Publication Date: 2022.02.09 BG PLAST IMPIANTI SRL
  • EP3769930B1 patent drawingFigure 1
  • EP3769930B1 patent drawingFigure 2
  • EP3769930B1 patent drawingFigure 3

AI summary

A method is described for the production of panels in thermoplastic material (P) consisting of a central three-dimensional strip element (P1) obtained by means of a first extrusion assembly (11) that feeds a first cylinder (13), shaped to give this strip a three-dimensional effect, and two flat strip covering elements (P2), P3) firmly connected to the central three-dimensional strip element (P1), obtained by continuous extrusion of a second strip (P2) and a third strip (P3) by means of a second extrusion assembly (21) and a third extrusion assembly (31) that feed respectively a second cylinder (22) and a third cylinder (32) respectively, said first, second and third cylinders (13, 23, 33) being in proximity one to the other, wherein said central three-dimensional strip element (P1) leaving the cylinder (13) is coupled due to the intrinsic heat of the extruded material and of the pressure to one of the flat strip elements (P2) in the gap between the two cylinders (13), 23) and wherein the composite structure thus obtained is in turn coupled due to the intrinsic heat of the extruded material and the pressure to the other flat strip covering element (P3) in the gap between the two cylinders (23, 33).