Dry-Ice Blasting for Conformal Coating Removal on PCBs
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Solution Overview
Problem
Existing methods for removing conformal coatings from circuit boards, such as plasma processing, solvent use, and mechanical scraping, are expensive and can damage the circuit board, necessitating a more inexpensive and reliable method.
Innovation Solution
A method involving a jet of dry-ice ejected from a nozzle, optionally with air, is used to remove conformal coatings from circuit boards, with specific nozzle configurations to control particle size and air pressure, minimizing damage and effectively removing the coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plasma processing is used to remove conformal coating, then coating removal is achieved, but cost increases and circuit board damage may occur
Solution Approach 1:
The patent replaces plasma processing (electromagnetic/thermal system) with dry-ice blasting (mechanical system). Dry ice particles impact the conformal coating and fracture it, enabling removal without the high cost and potential damage of plasma processing. This mechanical approach achieves reliable coating removal while reducing process cost.
Solution Approach 2:
The patent utilizes the phase transition of dry ice from solid to gas. Dry ice particles (solid) impact and fracture the conformal coating, then sublimate to gas, leaving no residue. This phase transition enables effective coating removal without the need for plasma processing, addressing both cost and effectiveness requirements.
2Reliability
If solvents are used to remove conformal coating, then coating removal is achieved, but circuit board damage occurs
Solution Approach 1:
The patent replaces chemical solvent-based removal with mechanical dry-ice blasting. The dry ice particles physically impact and fracture the conformal coating through mechanical force, eliminating the need for solvents that could damage circuit traces, components, or the board substrate. This mechanical approach achieves reliable removal without chemical harm.
Solution Approach 2:
The patent converts the cold temperature of dry ice (which could potentially cause thermal shock damage) into a beneficial feature. The cold dry ice particles sublimates rapidly upon contact with the conformal coating, creating a fracturing effect that enhances removal effectiveness while the brief exposure time minimizes thermal damage risk to the circuit board.
3Reliability
If mechanical scraping is used to remove conformal coating, then coating removal is achieved, but circuit board damage occurs
Solution Approach 1:
The patent replaces conventional mechanical scraping with dry-ice blasting. The dry ice particles impact the conformal coating at high velocity, causing fracture and removal without requiring contact with scraping tools that could mechanically damage circuit traces, components, or the board structure. This non-contact mechanical approach achieves effective removal while minimizing physical damage.
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 method provides a cost-effective and reliable way to remove conformal coatings without damaging the circuit board, using dry-ice blasting with controlled nozzle parameters to ensure efficient coating removal.
Implementation Method 1
subjecting the circuit board to a jet comprising dry-ice ejected from a nozzle, to remove said conformal coating from said circuit board
Implementation Method 2
a jet comprising dry-ice ejected from a nozzle
Data Source
AI summary
A method of removing a conformal coating from a circuit board coated with said conformal coating, the method comprising: subjecting the circuit board to a jet comprising dry-ice ejected from a nozzle, to remove said conformal coating from said circuit board.