Inert Enclosure Flow Obstructers for Wave Soldering Oxide Control

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Solution Overview

Problem

Conventional inert environment enclosures in wave soldering machines allow air and gases to enter during the production process, leading to oxide formation and equipment downtime, as well as environmental hazards due to lead oxide creation.

Innovation Solution

An inert environment enclosure with top-side and bottom-side flow obstructers, made of flexible materials, and a gas inlet system that maintains positive pressure within the enclosure, preventing gas entry and reducing nitrogen usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional nitrogen hoods are used to reduce oxygen, then oxide formation is decreased, but air still enters through inlet and outlet openings during production

Engineering Contradiction:

Improveoxide formationVSAvoidinert environment maintenance

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies flexible curtains made of heat-resistant material at the inlet and outlet openings. These curtains act as flexible barriers that seal around production boards during operation, preventing air infiltration while allowing continuous production flow. The flexible nature enables the curtains to conform to the moving boards while maintaining the inert atmosphere boundary.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The curtains serve as an intermediary element between the inert nitrogen environment inside the hood and the ambient air outside. They mediate the interface at opening/closing points, allowing production boards to pass through while blocking air exchange, thus protecting the inert environment without requiring complete sealing of the openings.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If curtains are added to reduce air flow through openings, then air infiltration is reduced, but nitrogen consumption increases

Engineering Contradiction:

Improveinert environment maintenanceVSAvoidnitrogen consumption

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

Instead of attempting to seal the entire hood or using excessive nitrogen flow to prevent air infiltration, the patent applies partial action by using curtains only at the critical inlet and outlet openings where air infiltration occurs during board passage. This targeted approach reduces nitrogen consumption compared to complete enclosure sealing while still achieving the primary goal of preventing oxide formation.

Inventive Principle:

Principle #16Partial or excessive action

3Productivity

If conventional wave soldering is used, then production speed is maintained, but oxide formation consumes valuable solder and requires preventative maintenance

Engineering Contradiction:

Improvesoldering speedVSAvoidsolder consumption

Core Design Contradiction:

ProductivityVSLoss of substance

Solution Approach 1:

The patent maintains a continuous inert nitrogen atmosphere within the hood enclosure, including at the inlet and outlet openings where curtains are positioned. This inert environment prevents oxygen from contacting the molten solder and hot components during the wave soldering process, eliminating oxide formation that would otherwise consume solder and require preventative maintenance, while allowing uninterrupted high-speed production.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

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

The solution effectively minimizes gas entry into the enclosure, reducing oxide formation and environmental hazards, while maintaining a stable internal pressure to prevent air infiltration, thus enhancing the operational efficiency and reducing maintenance downtime.

Implementation Method 1

a gas inlet system that maintains positive pressure within the enclosure, preventing gas entry

Methodology Applied

Scientific EffectPositive pressure: Pressure Gradient

Implementation Method 2

at least one of the object inlet and the object outlet includes a top-side flow obstructer and a bottom-side flow obstructer for inhibiting gases from the exterior of the enclosure from entering the interior of the enclosure

Methodology Applied

Scientific EffectFlow obstruction:

Data Source

PatentUS8104662B2Inert environment enclosure

Publication Date: 2012.01.31 FLEXTRONICS AP LLC

AI summary

A novel inert environment enclosure includes an object inlet where production objects enter the enclosure and an object outlet where the production objects exit. At least one of the object inlet and the object outlet includes both a top-side flow obstructer and a bottom-side flow obstructer for preventing air from entering the enclosure. In a particular embodiment, the top-side flow obstructer and the bottom-side flow obstructer each include a curtain constructed from a flexible fabric having a plurality of individual adjacent fingers. In another particular embodiment, the inert environment enclosure is a nitrogen hood that houses a wave soldering machine. A inert gas nozzle is mounted at or near the inlet and/or the outlet. The inert environment enclosure maintains a positive pressure with respect to the surrounding environment when production objects are passed through the enclosure.