Solder Paste Bead Recovery for Faster PCB Stencil Changeover

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Solution Overview

Problem

Current stencil printers require manual intervention for routine operations such as changing stencils, replacing solder paste cartridges, and recovering solder paste from stencils scheduled for replacement, leading to inefficiencies and downtime in PCB fabrication.

Innovation Solution

The integration of a print head assembly with a paste pan system that automates the recovery and transfer of solder paste from a stencil scheduled for replacement, allowing for automated tooling changeover and replenishment without human intervention, using a squeegee blade to roll the solder paste bead onto a new stencil.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual intervention is used for stencil replacement and solder paste recovery, then the operator can perform the tasks, but the changeover time increases significantly (up to 30 minutes) and productivity decreases

Engineering Contradiction:
Improvemanual operation capabilityVSAvoidchangeover speed
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The system enables automated self-service through the paste recovery device that automatically collects excess solder paste from the stencil and transfers it to storage containers, eliminating the need for manual intervention in paste recovery operations during stencil changes

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The paste recovery device is pre-positioned and pre-configured to automatically capture and store solder paste before the stencil is fully removed, allowing changeover operations to proceed without manual paste collection steps

Inventive Principle:
Principle #10Preliminary action

2Loss of substance

If manual recovery of solder paste from stencil is performed, then the paste can be saved for later use, but the process takes significant time and reduces fabrication line efficiency

Engineering Contradiction:
Improvesolder paste recoveryVSAvoidrecovery time
Core Design Contradiction:
Loss of substanceVSLoss of time

Solution Approach 1:

The paste recovery device automatically performs the recovery function without manual operation, with the system self-activating to collect and store solder paste during stencil changeover operations

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The automated recovery system operates continuously during the stencil changeover process, capturing solder paste in real-time without interruption to the overall changeover flow, thereby minimizing time loss while maximizing paste recovery

Inventive Principle:
Principle #20Continuity of useful action

3Productivity

If automated paste recovery system is implemented, then changeover time is reduced and productivity improves, but device complexity increases

Engineering Contradiction:
Improvechangeover efficiencyVSAvoidsystem automation level
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The paste recovery device is designed to perform multiple functions: collecting excess paste, transferring it to storage containers, and integrating with the stencil changeover mechanism, thereby consolidating several operations into a single automated system that manages complexity through functional integration

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 automation significantly reduces the time required for changeover operations, enabling continuous operation of the PCB fabrication line by efficiently recovering and reusing solder paste, thereby improving production efficiency and minimizing manual intervention.

Implementation Method 1

a squeegee blade to roll the solder paste bead onto a paste pan

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP3983233B1Solder paste bead recovery system and method
Publication Date: 2024.04.10 ILLINOIS TOOL WORKS INC
  • EP3983233B1 patent drawingFigure 1
  • EP3983233B1 patent drawingFigure 2
  • EP3983233B1 patent drawingFigure 3

AI summary

A stencil printer is configured to print an assembly material on an electronic substrate. The stencil printer includes a frame, a stencil coupled to the frame, a support assembly coupled to the frame, and a print head gantry coupled to the frame. The print head gantry includes an elongate beam that rides along rails provided on the frame and a print head assembly supported by the print head gantry in such a manner that the print head assembly is configured to traverse the stencil during print strokes. The print head assembly includes a print head having a squeegee blade assembly configured to roll solder paste along the stencil. The stencil printer further includes a solder paste bead recovery system configured to remove a bead of solder paste from a top surface of the stencil and to deposit the bead of solder paste onto a new replacement stencil.