Extruded Plastic Wall Thickness Monitoring via Temperature

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Solution Overview

Problem

Current methods for production control of extruded plastic products, such as corrugated hoses, lack continuous and uninterrupted monitoring of wall thickness, requiring time-consuming sampling and disrupting production processes.

Innovation Solution

A method and device for continuous wall thickness monitoring using temperature measurements at multiple points along the extrusion line, where actual temperatures are detected and compared to target temperatures calculated using a cooling curve, allowing for real-time adjustments to maintain wall thickness within specified tolerances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sampling methods are used for wall thickness inspection, then production control is achieved, but production is interrupted and time is lost

Engineering Contradiction:
Improveproduction controlVSAvoidproduction continuity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent replaces physical sampling and mechanical measurement methods with optical detection (infrared temperature measurement). Temperature sensors detect the temperature of the extruded product continuously, and wall thickness is calculated from temperature differences between the product surface and ambient air, eliminating the need to stop production for sampling

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

Solution Approach 2:

The detection system operates continuously during extrusion, with temperature measurements taken at multiple points along the extrusion line. The system provides uninterrupted monitoring of wall thickness throughout the production process, maintaining both quality control and production continuity

Inventive Principle:
Principle #20Continuity of useful action

2Manufacturing precision

If continuous temperature monitoring is implemented, then wall thickness control is improved, but measurement complexity increases

Engineering Contradiction:
Improvewall thickness controlVSAvoidmeasurement system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent uses temperature as an intermediary parameter to indirectly measure wall thickness. Instead of directly measuring wall thickness with complex sensors, the system measures temperature at the product surface and uses the relationship between temperature and wall thickness (based on heat transfer principles) to calculate wall thickness

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system monitors changes in temperature parameters along the extrusion direction and uses these temperature variations to detect wall thickness variations. By tracking temperature gradients and their changes over time and position, the system infers wall thickness without direct mechanical measurement

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

Enables 100% production control during operation, eliminating the need for sampling and ensuring uninterrupted production by continuously monitoring and adjusting wall thickness, maintaining it within precise tolerance ranges.

Implementation Method 1

acquiring a first actual temperature of a measuring area provided on the plastic product at a first measuring point; acquiring a second actual temperature of the measuring area at a second measuring point

Methodology Applied
Scientific EffectTemperature measurement:

Implementation Method 2

determining a target temperature of the measuring area at the second measuring point, wherein the target temperature is calculated based on the first actual temperature using a cooling curve of the plastic product

Methodology Applied
Scientific EffectCooling: Cooling

Data Source

PatentEP3658349B1Method and device for the production control of an extruded plastics product and extrusion installation for extruding such a plastics product
Publication Date: 2023.06.07 DELFINGEN FR ANTEUIL
  • EP3658349B1 patent drawingFigure 1
  • EP3658349B1 patent drawingFigure 2
  • EP3658349B1 patent drawingFigure 3

AI summary

A method for the production control of an extruded plastics product (1) with the following steps: recording (S1) a first actual temperature (TI1) of a measuring area (22 - 25) provided on the plastics product (1) at a first measuring point (30), recording (S2) a second actual temperature (TI2) of the measuring area (22 - 25) at a second measuring point (31), which is arranged at a distance from the first measuring point (30) in a direction of extrusion (E) of the plastics product (1), determining (S3) a setpoint temperature (TS) of the measuring area (22 - 25) at the second measuring point (31), and outputting (S4) information on whether the second actual temperature (TI2) lies inside or outside a prescribed tolerance range (TB1) of the setpoint temperature (TS).