Liquid Media PCB Rework for Low-Damage Component Removal
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Solution Overview
Problem
Existing methods for reworking electronic components on printed circuit boards, such as hot-air and laser IR systems, often cause excessive peak temperatures and thermal gradients, damaging the board and components, while vapor phase reflow systems are costly and environmentally regulated.
Innovation Solution
A liquid media rework system that uses a heating well and rework head with sealing heads and a mechanical capture device to apply and control a heated liquid that exceeds the solder's melting point, allowing for precise temperature control and efficient removal and replacement of components without excessive heat damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If hot air gun or hot air station is used to heat devices, then solder melting is achieved, but excessive peak temperatures and thermal gradients damage the board and components
Solution Approach 1:
A liquid media is introduced as an intermediary between the heat source and the PCB assembly. The liquid media absorbs excess thermal energy through phase change (evaporation), preventing direct thermal shock to components while still achieving solder melting. This mediator controls the thermal transfer process to avoid harmful temperature spikes.
Solution Approach 2:
The liquid media undergoes phase transition from liquid to vapor during the rework process. This phase change absorbs significant thermal energy (latent heat of vaporization), acting as a thermal buffer that prevents excessive temperature rise in the PCB and components while maintaining sufficient heat transfer to melt the solder joints.
2Temperature
If vapor phase reflow systems are used, then controlled heating is achieved, but high cost and environmental regulation issues arise
Solution Approach 1:
The system uses a disposable or easily replaceable liquid media reservoir instead of expensive, regulated vapor phase systems. The liquid media can be simple, inexpensive substances that are applied locally and evaporated, eliminating the need for complex vapor generation systems and environmental compliance infrastructure.
Solution Approach 2:
The invention extracts only the essential function of vapor phase reflow (controlled heating through phase change) while removing the complex and expensive vapor generation system. By applying liquid media directly to the target area and allowing it to evaporate naturally or with minimal heating, the system achieves temperature control without the regulatory and cost burdens of traditional vapor phase systems.
3Manufacturing precision
If mechanical capture device is used to remove component, then precise component removal is achieved, but device complexity increases
Solution Approach 1:
The mechanical capture device is integrated into the rework head assembly, combining component capture functionality with the heating and liquid media application system. This merging reduces the number of separate tools and devices needed, simplifying the overall system while maintaining precise component removal capability through coordinated operation of the capture mechanism with the thermal processing.
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 system reduces damage to solder joints and components, recaptures rework fluid for reuse, and supports a wide range of component types, minimizing environmental impact and operational costs.
Implementation Method 1
a heating well configured to hold a rework liquid
Implementation Method 2
The rework liquid may be at a temperature that is higher than the melting point of solder used to attach the electronic component to the PCB
Data Source
AI summary
Provided is a system for removing an electronic component from a printed circuit board (PCB). The system may comprise a heating well configured to hold a rework liquid. The system may further comprise a head system configured to create a liquid-tight seal around an electronic component. The system may further comprise a nozzle and a mechanical capture device disposed within the head system. The mechanical capture device may be configured to attach to the electronic component. The system may further comprise a controller. The controller may be configured to release the rework liquid through the nozzle and onto the electronic component and lift the electronic component off the PCB.