Jet Nozzle Solder Flow Control for Oxidation Prevention

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Solution Overview

Problem

Point flow soldering apparatuses face issues with solder oxidation and clogging due to exposure to air, requiring inert gas environments, which increase installation and running costs, and struggle to fill through holes effectively with lead-free solder, leading to poor reliability and efficiency.

Innovation Solution

The apparatus circulates molten solder within the jet nozzle, preventing it from flowing outside, and uses a screw pump to dispatch solder, ensuring it only exits through the insert hole during soldering, thereby minimizing oxidation and clogging, and filling through holes reliably without inert gases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If molten solder is always flown out through a small sized nozzle outlet for point flow soldering, then soldering can be performed, but the solder is subject to oxidation and oxide generated becomes hard in the nozzle outlet so as to be easily stuffed therein

Engineering Contradiction:
Improvesoldering capabilityVSAvoidnozzle clogging
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies inert atmosphere by introducing nitrogen gas into the solder bath and maintaining a nitrogen atmosphere in the nozzle interior. This prevents oxidation of the molten solder that flows through the small nozzle outlet, eliminating the formation of hard oxide that would cause clogging. The nitrogen atmosphere is maintained throughout the soldering process while allowing continuous solder flow for productivity.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

2Reliability

If a cover and nitrogen atmosphere are provided around the jet nozzle to prevent oxidation, then solder oxidation is prevented, but installation space and costs increase

Engineering Contradiction:
Improveoxidation preventionVSAvoidapparatus structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the nitrogen atmosphere requirement from the external environment and places it directly inside the nozzle. Instead of surrounding the nozzle with a nitrogen-filled cover, the invention introduces nitrogen into the solder bath and allows it to penetrate the nozzle interior, eliminating the need for external covers and complex apparatus structures while maintaining oxidation prevention.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent nests the nitrogen atmosphere within the nozzle structure itself by introducing nitrogen gas that fills the nozzle interior space. This nested approach allows the inert atmosphere to be contained within the existing nozzle geometry without requiring external protective structures, reducing device complexity while maintaining reliability.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Adaptability or versatility

If lead-free solder is used for environmental reasons, then environmental compliance is achieved, but melting temperature increases to about 220°C requiring higher heat-resistant property

Engineering Contradiction:
Improveenvironmental complianceVSAvoidmelting temperature
Core Design Contradiction:
Adaptability or versatilityVSTemperature

Solution Approach 1:

The patent addresses the higher melting temperature of lead-free solder by optimizing the heating parameters of the solder bath and controlling the thermal environment. The system maintains the solder bath at temperatures sufficient to melt lead-free solder (around 220°C) while controlling heat distribution to prevent excessive thermal exposure to components, enabling environmental compliance while managing temperature requirements.

Inventive Principle:
Principle #35Parameter changes

4Adaptability or versatility

If manual soldering is performed to accommodate components without heat-resistant property, then component compatibility is improved, but work efficiency decreases and quality varies

Engineering Contradiction:
Improvecomponent compatibilityVSAvoidwork efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent replaces manual soldering operations with an automated point flow soldering system. The automated nozzle precisely delivers molten solder to designated locations, eliminating the need for manual intervention while maintaining the ability to accommodate various components. This substitution achieves both high productivity through automation and component compatibility through precise control of the soldering process parameters.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 configuration prevents solder oxidation, reduces clogging, and enhances reliability by maintaining stable solder flow and complete hole filling, eliminating the need for inert gases and improving efficiency.

Implementation Method 1

a screw pump, which dispatches the solder, in the solder bath

Methodology Applied
Scientific EffectScrew pump: Screw

Implementation Method 2

the through hole of the printed circuit board is filled with the molten solder

Methodology Applied
Scientific EffectPressure-driven flow: Pressure Gradient

Data Source

PatentEP2373138B1Point flow soldering apparatus
Publication Date: 2013.08.21 SENJU METAL IND CO LTD
  • EP2373138B1 patent drawingFigure 1~2
  • EP2373138B1 patent drawingFigure 3~4
  • EP2373138B1 patent drawingFigure 5

AI summary

To prevent clogging in a jet nozzle without using any inert gas and to allow reliability to be improved by filling a through hole of a printed circuit board with the molten solder. By flowing the molten solder 4 in the solder bath 2 from inside of the inner cylinder 15 to a nozzle cap 19, the inside of the nozzle cap 19 is filled with the molten solder 4, and the molten solder 4 filling the inside of the nozzle cap 19 is flown downward from between an inner cylinder 15 and an outer cylinder 16 without substantially flowing it to outside from an insert hole 19a. This enables the molten solder 4 to be prevented from oxidizing because the molten solder 4 is not exposed to the outside air. For this reason, it is possible to prevent clogging in the jet nozzle 3 without filling a part of nozzle outlet with any inert gas as in the conventional soldering apparatus. Further, since the soldering is performed with a lead 31 of electronic component 30 being inserted into the insert hole 19a, it is possible to fill the through hole of the printed circuit board P with the molten solder 4, so that the reliability can be improved.