Adhesive Dispensing Bubble Detection and In-Path Void Repair
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Solution Overview
Problem
Adhesives, sealants, and mastics often contain entrapped air bubbles during dispensing, leading to voids and bond discontinuities, which are not effectively detected or repaired by existing methods.
Innovation Solution
A method using a robotic material dispensing system with a pressure transducer to detect pressure discontinuities during dispensing, determining defect location and size, and redirecting the nozzle to apply additional material for repair, ensuring consistent application and sealing on a moving assembly line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional dispensing methods are used without real-time detection, then the dispensing process is simple and fast, but defects such as voids and bond discontinuities caused by entrapped air bubbles cannot be detected or repaired
Solution Approach 1:
The patent implements a feedback mechanism where a pressure transducer continuously monitors pressure during dispensing, and when a pressure discontinuity is detected (indicating an air bubble), the system automatically redirects the nozzle to repair the defect. This closed-loop feedback system enables real-time defect detection and repair without requiring complex external inspection equipment.
Solution Approach 2:
The dispensing system performs self-diagnosis and self-repair by using the pressure transducer to detect air bubbles within the material stream and automatically redirecting the nozzle to apply additional material at the defect location. The system serves itself by detecting and correcting its own defects without external intervention.
2Reliability
If the nozzle redirects to repair defects on a moving assembly line, then defect repair capability is achieved, but the dispensing cycle time increases
Solution Approach 1:
The system performs preliminary detection of defects during the normal dispensing process itself, rather than requiring a separate inspection step. The pressure monitoring occurs concurrently with material application, allowing defects to be identified and repaired within the same dispensing cycle without adding significant time overhead.
Solution Approach 2:
The pressure monitoring and defect detection occur continuously during the entire dispensing process, not as an interrupt or separate step. The system maintains continuous material flow and continuous pressure monitoring, ensuring that the useful action of dispensing is not interrupted while still enabling real-time defect detection and repair.
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 approach enables real-time detection and repair of defects, ensuring high-quality adhesion and sealing by addressing voids and skips in the dispensed material, improving the reliability and efficiency of adhesive application processes.
Implementation Method 1
A pressure discontinuity is detected when a gas bubble in the material flows past a pressure transducer
Data Source
AI summary
A method of detecting a defect in an applied volume of material includes detecting a pressure discontinuity during dispensing the volume of material along a predetermined path on a substrate. The pressure discontinuity is indicative of the defect in the applied volume of material. The location of the defect along the predetermined path is function of a start time of the pressure discontinuity and the size of the defect is a function of a time duration of the pressure discontinuity. The method can further include determining whether or not to repair the defect as a function of the location and the size of the defect in the applied volume of material. The method includes repairing the defect by re-directing the material applicator to the location of the defect and dispensing additional material at the location of the defect.