Thin-Film Sensor Integration for Real-Time Joining Process Control

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Solution Overview

Problem

Current joining methods, particularly heat contact processes, face challenges in ensuring the safety and quality of joint seams due to inadequate real-time control of process parameters, leading to issues like contamination, layer cracks, and inefficient material processing, especially with thin materials at high speeds, resulting in premature functional failure and product spoilage.

Innovation Solution

A joining device equipped with thin-film sensors on the tool halves for continuous detection of process parameters like temperature, pressure, and distance, integrated with an evaluation and control unit to adjust these parameters in real-time, ensuring precise control and quality of the joining seam.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional temperature sensors (PT100/PT1000) are used for monitoring joining temperature, then the sensor structure is simple and cost-effective, but the sensor responds slowly to temperature changes at high processing speeds

Engineering Contradiction:
Improveprocessing speedVSAvoidtemperature measurement response time
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

The patent replaces conventional mechanical contact temperature sensors (PT100/PT1000) with infrared sensors that measure temperature wirelessly through radiation. This substitution eliminates the mechanical contact limitation and enables fast, contactless temperature measurement that keeps pace with high-speed processing while maintaining measurement accuracy.

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

2Reliability

If manual or batch inspection methods are used for weld seam quality control, then the inspection process is simple to implement, but numerous defective packages are produced before errors are detected

Engineering Contradiction:
Improveweld seam quality assuranceVSAvoidtime delay in error detection
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent implements real-time feedback control by continuously monitoring weld seam quality parameters during the joining process and immediately adjusting process parameters when deviations are detected. This closed-loop feedback system ensures high reliability by preventing defective packages rather than detecting them after production, eliminating the time delay inherent in batch inspection methods.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary quality assessment by monitoring process parameters and predicting potential defects before they occur. By detecting deviations in real-time and adjusting parameters proactively, the system prevents the production of defective packages rather than identifying them after the fact.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If uniform heating across the entire tool surface is applied, then the heating process is simple to control, but the narrow process window makes it difficult to melt thin layers without damaging thick layers at layer transitions

Engineering Contradiction:
Improveselective layer melting controlVSAvoidheating control system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality control by using multiple independently controllable heating zones or selectively activatable heating elements that can be tailored to match the local material thickness and composition. This allows precise control of energy input at each location, enabling thin layers to be melted adequately while preventing overheating of thick layers at transition areas.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The heating system transitions from static uniform heating to dynamic selective heating where the heating pattern can be adjusted in real-time based on detected material variations. The system dynamically modifies heating parameters across different zones to accommodate changing material conditions during the joining process.

Inventive Principle:
Principle #15Dynamics

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 solution enables immediate, precise control of the joining process, reducing rejects, ensuring product safety, and improving process efficiency by detecting deviations and adjusting parameters inline, thus enhancing the quality and durability of the joint seams.

Implementation Method 1

at least one first thin-film sensor arranged on a surface of the first tool half... configured to detect at least one process parameter value... during a joining process

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

thin-film sensors for continuous detection of process parameters like temperature, pressure, and distance

Methodology Applied
Scientific EffectPiezoresistive effect: Piezoresistive Effect

Implementation Method 3

Continuously heated tools melt layers of film and bond them together

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 4

The heat contact process... continuously heated tools melt layers of film

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 5

integrated with an evaluation and control unit to adjust these parameters in real-time

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 6

continuously heated tools melt layers of film and bond them together

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP3168032B1Joining device and joining method
Publication Date: 2019.02.27 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP3168032B1 patent drawingFigure 1~2
  • EP3168032B1 patent drawingFigure 3
  • EP3168032B1 patent drawingFigure 4a~4b

AI summary

The invention relates to a joining device (1), in particular for contact-based joining of flexible materials, comprising a first tool half (1a) and at least one first thin-film sensor (6a) arranged on a surface (2a) of the first tool half (1a), wherein the at least one first thin-film sensor (6a) is configured to detect at least one process parameter value, preferably continuously, during a joining process. The invention further relates to a joining method in which at least one process parameter value is detected on a surface (2a) of at least one first tool half (1a) by means of at least one first thin-film sensor (6a).