Viscous Droplet Ejector with In-Flight Sensor Detection
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Solution Overview
Problem
Current ejector systems for jetting viscous media, such as solder paste or adhesive, face challenges in ensuring accurate and reliable deposition on substrates due to limited ability to detect small volume variations and the need for time-consuming downstream inspections, which can lead to defects like dry joints or short-circuiting.
Innovation Solution
An ejector system equipped with a sensor arrangement along the path of jetted droplets that monitors the jetting process in real-time, allowing for immediate detection of missed drops and volume inaccuracies, enabling on-the-fly corrections and reducing the need for subsequent inspections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If downstream optical inspection is performed to detect volume variations, then process reliability is improved, but time consumption and complexity increase
Solution Approach 1:
The patent applies preliminary action by performing droplet detection upstream before the substrate reaches the inspection station. The sensor arrangement detects droplet passage and monitors deposition accuracy in real-time during the jetting process, allowing early identification of defects such as missed droplets or volume variations. This upstream monitoring eliminates the need for time-consuming downstream optical inspection while maintaining high process reliability.
2Manufacturing precision
If downstream inspection is performed to ensure deposition accuracy, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex downstream optical inspection systems with a simpler sensor arrangement that detects droplet passage through electromagnetic or capacitive sensing. The sensor arrangement monitors whether droplets are properly jetted and deposited by detecting their passage through the sensor field, providing real-time feedback on deposition accuracy without requiring complex optical equipment. This substitution maintains manufacturing precision while significantly reducing device complexity.
3Productivity
If real-time monitoring is implemented, then productivity is improved through on-the-fly corrections, but device complexity increases
Solution Approach 1:
The patent implements feedback by using the sensor arrangement to monitor droplet passage and deposition in real-time, then feeding this information back to the jetting system. The system can detect missed droplets or volume variations and automatically trigger corrective jetting actions to compensate for defects. This closed-loop feedback mechanism enables on-the-fly corrections that maintain high productivity without requiring complex downstream inspection and rework processes.
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 enhances the reliability and accuracy of viscous medium deposition by allowing real-time monitoring and correction of jetting errors, improving production yield and reducing reworking and inspection costs, while ensuring consistent quality of printed circuit board assemblies.
Implementation Method 1
a sensor arrangement, arranged along a path of the jetted droplets of the viscous medium, adapted to detect passage of the jetted droplets of the viscous medium towards the substrate
Data Source
AI summary
An ejector for jetting droplets of viscous media onto a substrate is disclosed. The ejector comprises a jetting nozzle having a nozzle space and a nozzle outlet, and an impacting device for impacting a volume of the viscous medium in the nozzle space such that droplets of viscous medium is jetted from the nozzle space through the nozzle outlet towards the substrate. The ejector also comprise a sensor arrangement arranged after the jetting nozzle in the jetting direction, wherein the sensor arrangement is adapted to detect a jetted droplet of viscous medium passing thereby.