Cap-Based Multi-Level PCB Potting via Vacuum Pressure

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Solution Overview

Problem

Existing methods for encapsulating printed circuit boards (PCBs) with potting materials often result in excessive material depth due to the need to cover the tallest component, leading to inefficiencies and increased complexity, cost, and technical risks in achieving multi-level potting heights.

Innovation Solution

A method involving a housing assembly with a cap that covers components extending beyond the PCB surface, applying a vacuum to evacuate the cap's interior, and then introducing an encapsulant, which flows into the cap under atmospheric pressure differential, allowing for a lower overall potting level while ensuring adequate protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the potting height is increased to cover the tallest component, then all components are protected, but the encapsulant depth becomes excessive in areas where it is not needed

Engineering Contradiction:
Improvecomponent protectionVSAvoidencapsulant amount
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The housing is divided into a first portion and a second portion, with the second portion forming a cap that extends over the tallest component. This segmentation allows different potting heights in different areas: the first portion receives encapsulant to a first height, while the second portion (cap) provides localized protection for the tallest component without requiring excessive encapsulant depth throughout the entire housing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The cap structure provides localized protection where needed (over the tallest component) while allowing reduced encapsulant depth in other areas. The opening in the cap allows encapsulant to be introduced and provides localized protection where needed while maintaining lower overall potting levels in non-critical areas, optimizing material usage while ensuring adequate protection where required.

Inventive Principle:
Principle #3Local quality

2Quantity of substance

If multi-level potting heights are implemented to match different component heights, then encapsulant usage is optimized, but the process becomes complex and expensive

Engineering Contradiction:
Improveencapsulant amountVSAvoidpotting process complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The cap is pre-installed on the housing before the encapsulant is introduced. This preliminary action creates the multi-level structure in advance, allowing the encapsulant to be introduced as a single material without requiring complex multi-step potting processes. The cap itself establishes the different height levels needed, simplifying the subsequent encapsulant application process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The cap acts as an intermediary structure that enables multi-level potting heights without requiring complex multi-material or multi-step processes. By introducing the cap as a intermediate component, the system achieves differentiated protection levels while using a single encapsulant material and a simplified single-step potting process.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Quantity of substance

If the potting height is reduced to decrease encapsulant usage, then material efficiency improves, but the tallest component may not be adequately protected

Engineering Contradiction:
Improveencapsulant amountVSAvoidcomponent protection
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The housing is segmented into a first portion for general component protection and a second portion (cap) for tallest component protection. This segmentation allows the encapsulant depth to be reduced in the first portion while the cap extends the protection height specifically where the tallest component requires it, maintaining adequate protection while reducing overall material usage.

Inventive Principle:
Principle #1Segmentation

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 approach reduces the amount of encapsulant needed, simplifies the process, and achieves a multi-level potting height without increased processing times, while ensuring effective protection of components.

Implementation Method 1

A pressure differential is formed between an environmental pressure level and a pressure level within the cap. The pressure differential causes encapsulant to flow from the housing into the cap interior.

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Implementation Method 2

applying predetermined vacuum to the housing assembly, and then after applying the vacuum, introducing an encapsulant through the opening of the housing

Methodology Applied
Scientific EffectVacuum: Vacuum

Data Source

PatentEP3682720B1System for potting components using a cap
Publication Date: 2021.10.27 HELLA GMBH & CO KGAA
  • EP3682720B1 patent drawingFigure 1
  • EP3682720B1 patent drawingFigure 2~3
  • EP3682720B1 patent drawingFigure 4

AI summary

A housing assembly includes a housing, a printed circuit board (PCB) contained in a housing, and a cup-shaped cap having an interior and a flange portion. A tall component extending from the PCB is covered by the cap such that the tall component is disposed in the interior of the cap and the flange portion of the cap engages the PCB. A vacuum is applied and while maintaining the vacuum, an encapsulant is introduced into the housing to a level so as to cover the PCB and certain other components not the relatively taller component(s). When the vacuum is released, a pressure differential between the environmental pressure and the vacuum remaining in the cap interior forces encapsulant into the cap interior to a level higher than that outside of the cap. A multi-level height potting process is achieved.