Sensor-Based Rework Nozzle for Soldered Component Removal
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Solution Overview
Problem
The rework process of surface mount connectors on printed circuit boards is complicated due to large connector dimensions, making it difficult to remove solder joints without damaging the board, often resulting in pad lift, barrel damage, and excessive heat cycles, which can lead to catastrophic defects.
Innovation Solution
A sensor-based rework nozzle with a grip mechanism and spring system that detects the melting of solder joints, preventing premature removal and ensuring safe detachment by communicating a signal to activate the nozzle only when the solder has melted sufficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If hot air is channeled across the span of the connector to reflow all solder joints, then all solder joints are heated uniformly, but the temperature constraints of the connector housing are exceeded
Solution Approach 1:
The patent applies local quality by using multiple localized heating zones rather than a single uniform heat source. Each heating element targets specific solder joints individually, allowing precise temperature control at each location while keeping the overall connector housing temperature within safe limits. This resolves the contradiction by achieving uniform solder reflow through distributed local heating rather than global heating.
Solution Approach 2:
The heating system is segmented into multiple independent heating elements distributed across the connector span. Each segment can be controlled independently to heat specific solder joints, enabling precise thermal management that achieves uniform solder reflow without overheating the connector housing as a whole.
2Productivity
If removal is attempted before solder joints are fully melted, then the rework process is faster, but pad lift and barrel damage occur
Solution Approach 1:
The patent implements feedback control by using sensors to detect the melting state of solder joints in real-time and providing feedback signals to control the heating process. This ensures that removal is only attempted when solder joints are fully melted, preventing pad lift and barrel damage while maintaining efficient rework throughput through automated monitoring.
Solution Approach 2:
The system performs preliminary detection of solder melting status before allowing removal to proceed. The sensors monitor the solder joints continuously during heating, and only when the melting criterion is met does the system enable the removal action, ensuring PCB integrity is maintained while optimizing the rework process timing.
3Manufacturing precision
If multiple heat cycles are applied to ensure complete solder melting, then solder joints are fully melted, but catastrophic latent defects are introduced
Solution Approach 1:
The feedback mechanism continuously monitors solder joint melting status and provides real-time information to the control system. This allows the process to stop heating as soon as complete melting is detected, eliminating the need for multiple excessive heat cycles and preventing heat-related damage to the PCB while ensuring thorough solder melting.
Solution Approach 2:
The patent replaces the traditional mechanical trial-and-error heating approach with a sensor-based detection system. Instead of applying fixed multiple heat cycles, the system uses optical or thermal sensors to detect solder melting and automatically adjusts the heating process, substituting intelligent sensing and control for brute-force thermal cycling.
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 reduces the risk of PCB damage by ensuring proper solder melting before removal, preventing pad lift and barrel damage, and minimizing heat cycles, thus enhancing the reliability and throughput of the rework process.
Implementation Method 1
move beyond a minimum threshold in response to an initiation of a melt of a solder that attaches the electrical component to the printed circuit board
Data Source
AI summary
An apparatus includes at least one grip mechanism of a rework nozzle configured to grip an electrical component that is soldered to a printed circuit board. The apparatus includes at least one spring coupled to at least one grip mechanism, where the spring is configured to move beyond a minimum threshold in response to an initiation of a melt of a solder that attaches the electrical component to the printed circuit board. The apparatus includes at least one sensor coupled to at least one spring, where the sensor is configured to detect the move of at least one spring beyond the minimum threshold. At least one sensor is configured to communicate at least one activate signal in response to detection of the move of one or more springs beyond the minimum threshold.