Removable Paste Shield for Squeegee Drip Control in Stencil Printers

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Solution Overview

Problem

Solder paste tends to drip off squeegee blades during stencil printer operations, contaminating the workspace and leading to defective printing on electronic substrates.

Innovation Solution

A squeegee drip collection system with a paste shield that can be extended under the squeegee blades to collect excess solder paste, featuring a mechanism for easy replacement and installation, controlled by a controller to manage the movement and switching of clean and full shields.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a paste shield is extended under the squeegee blade to collect dripping solder paste, then solder paste contamination is prevented, but the device complexity increases

Engineering Contradiction:
Improvesolder paste contaminationVSAvoiddevice complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The paste shield is designed as a separate, removable component that can be independently installed and removed from the stencil printer system. This segmentation allows the contamination prevention function to be added without permanently increasing the complexity of the core printing mechanism.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The paste shield is designed as a simple, inexpensive component that can be easily replaced when full or contaminated. This approach prevents the need for complex cleaning mechanisms or permanent maintenance systems, thereby avoiding long-term complexity increases.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Device complexity

If the paste shield is manually removed and replaced, then the structure remains simple, but the loss of time increases due to manual intervention

Engineering Contradiction:
Improvestructure simplicityVSAvoidtime for shield replacement
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The system incorporates a sensor that automatically detects when the paste shield is full and triggers an alert or automated response. This self-monitoring capability reduces the need for continuous manual checking and enables timely replacement without interrupting the printing workflow.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The sensor provides feedback about the paste shield's fill status to the control system, which can then automatically initiate replacement procedures or alert operators. This feedback loop minimizes manual intervention time by providing real-time information about when replacement is needed.

Inventive Principle:
Principle #23Feedback

3Manufacturing precision

If the paste shield collection system is implemented, then print quality consistency is improved, but the device complexity increases

Engineering Contradiction:
Improveprint quality consistencyVSAvoiddevice complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The paste shield acts as an intermediary component between the squeegee blade and the workspace/stencil. It intercepts and contains dripping solder paste before it can contaminate the printing area, thereby maintaining print quality without requiring modifications to the core printing mechanism.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The paste shield extracts and removes the harmful function (solder paste dripping) from the printing system. By isolating the contamination source in a separate collectable component, the main printing system remains simple while still achieving improved print quality consistency.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP4399093B1Squeegee drip collection system for stencil printer
Publication Date: 2026.04.08 ILLINOIS TOOL WORKS INC
  • EP4399093B1 patent drawingFigure 1
  • EP4399093B1 patent drawingFigure 2
  • EP4399093B1 patent drawingFigure 3

AI summary

A squeegee drip collection system is configured to receive assembly material from at least one squeegee blade of the print head assembly. The squeegee drip collection system includes a paste shield coupled to the print head gantry and configured to be moved between a retracted position in which the paste shield is spaced from the at least one squeegee blade and an extended position in which the paste shield is positioned under the at least one squeegee blade. The squeegee drip collection system further includes a paste shield removal assembly configured to uncouple the paste shield from the print head gantry and to remove the paste shield.