Surface Mount Component Thermal Venting via Differential Expansion

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Surface mount electronic components with hollow resin cases face issues with internal pressure changes during reflow soldering, leading to potential solder or adhesive flow into the casing, which can damage the internal components and affect electrical performance.

Innovation Solution

The integration of a sealing metal plate with a different coefficient of linear expansion than the resin case, which deforms to unseal the through hole during heating and reseal upon cooling, preventing internal pressure buildup and ensuring hermetic sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a through hole is formed in the case body to prevent internal pressure increase during reflow soldering, then the case can be protected from damage, but solder or adhesive may flow into the hollow casing part through the through hole

Engineering Contradiction:

Improvecase integrityVSAvoidsolder/adhesive contamination

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A sealing metal plate is preliminarily placed in the through hole before reflow soldering to prevent solder or adhesive from flowing into the hollow casing part. The sealing metal plate is positioned in advance to seal the through hole, and after the bonding process completes, the plate is removed, leaving the through hole open for pressure equalization.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The sealing metal plate is designed to be movable within the through hole, allowing it to dynamically seal the hole during bonding and then be removed afterward. This dynamic approach enables the through hole to serve dual purposes: preventing contamination during processing and allowing pressure equalization during operation.

Inventive Principle:

Principle #15Dynamics

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 effectively reduces the risk of solder or adhesive entering the hollow casing, maintaining the non-defective rate and ensuring secure hermetic sealing of the surface mount electronic component.

Implementation Method 1

The sealing metal plate has a coefficient of linear expansion that is different from a coefficient of linear expansion of the resin case so that deformation to unseal the through hole arise when heated

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

Methodology Applied

Scientific EffectThermal contraction: Thermal Contraction

Data Source

PatentUS9161473B2Surface mount electronic component

Publication Date: 2015.10.13 MURATA MFG CO LTD

AI summary

A surface mount electronic component that includes a resin case, metal terminals, and a sealing metal plate that are molded integrally by insert molding. A hollow casing part and a through hole are formed in the case. The through hole leads from the hollow casing part to a surface of the case. The metal plate seals the through hole. The metal plate has a coefficient of linear expansion that is different from a coefficient of linear expansion of the case so that deformation to unseal the through hole occurs when heated.