Wave Soldering Nozzle Monitoring via Spray Jet Imaging

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Solution Overview

Problem

Current soldering systems for selective wave soldering lack a reliable method to monitor the shape and position of spray jets and standing waves, particularly for wider jets or nozzles, as existing methods are limited to thin jets and do not account for nozzle contamination or blockage, and automated monitoring of soldering nozzles is not available.

Innovation Solution

A device with a test surface, such as a stretched paper web or transparent plate, and a digital camera is used to image and detect the shape and position of spray jets and standing waves, allowing for automated condition monitoring and comparison to target shapes and positions, with image processing to provide feedback on nozzle status.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a laser device is used to monitor the spray jet position, then the position can be detected, but this method can only be used with very thin spray jets (diameter < 5 mm) and cannot monitor wider spray jets (diameter 25-30 mm)

Engineering Contradiction:
Improvespray jet position detectionVSAvoidapplicability to different spray jet diameters
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

A test surface (transparent plate or paper web) is introduced as an intermediary between the spray jet and the camera. The spray jet is brought into contact with the test surface, creating a visible impression or wet mark that the camera can detect. This intermediary allows the camera to indirectly observe the spray jet shape and position without requiring direct optical penetration through the jet, thereby enabling monitoring of wide spray jets that were previously unmonitorable.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The test surface creates a copy or impression of the spray jet shape and position. When the spray jet contacts the test surface, it leaves a visible pattern (wet mark on paper or refractive pattern on transparent plate) that replicates the jet's geometry. The camera then detects this copied pattern instead of the jet itself, enabling measurement of wide spray jets that cannot be directly observed optically.

Inventive Principle:
Principle #26Copying

2Device complexity

If visual inspection is used for soldering nozzles, then no additional monitoring device is needed, but automated monitoring is not available and relies on manual inspection

Engineering Contradiction:
Improvemonitoring system structureVSAvoidautomated nozzle monitoring
Core Design Contradiction:
Device complexityVSExtent of automation

Solution Approach 1:

The test surface serves itself by automatically capturing the spray jet or standing wave pattern when the nozzle operates. The system requires no active components at the measurement location - the test surface passively records the jet pattern through contact, and the camera automatically captures the image. This self-service approach enables automated monitoring without complex active sensing devices at the measurement point.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The manual visual inspection process is replaced by an automated optical detection system. Instead of a human operator visually examining the nozzle, a camera captures images of the test surface pattern, and image processing algorithms automatically analyze the spray jet or standing wave characteristics. This substitutes mechanical/manual inspection with automated optical and computational methods.

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

3Area of stationary object

If the spray jet is allowed to wet a larger area, then better coverage is achieved, but laser-based monitoring becomes impossible as the jet leaves the nozzle in a fan shape

Engineering Contradiction:
Improvespray jet coverage areaVSAvoidspray jet position detection
Core Design Contradiction:
Area of stationary objectVSDifficulty of detecting and measuring

Solution Approach 1:

The detection method transitions from direct optical measurement in three-dimensional space to two-dimensional pattern capture on a test surface. By projecting the three-dimensional spray jet onto a two-dimensional test surface through contact, the system preserves the jet's shape and position information in a format that can be captured by a camera, even when the jet spreads out in a fan shape over a large area.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 reliable and independent monitoring of spray jets and standing waves regardless of diameter, detecting contamination or blockage, and ensuring proper nozzle operation, enhancing the accuracy and reliability of the soldering process.

Implementation Method 1

a stretched paper web (22), wherein a shape and/or position of the spray jet (12) on an upper side (24) of the paper web (22) is imaged by wetting the paper web (22) with the spray jet (12) from the lower side (26)

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentEP3651928B1Soldering systems with monitoring device and methods for monitoring
Publication Date: 2022.10.19 ERSA GMBH
  • EP3651928B1 patent drawingFigure 1
  • EP3651928B1 patent drawingFigure 2

AI summary

The invention relates to a soldering system and a method for wave soldering, comprising at least one flux nozzle (16) and a device (10) for monitoring a state of a spray jet (12) of said flux nozzle (16).