Through-Hole Land Soldering With Preliminary Solder Placement

Solution Overview

Problem

In circuit board soldering, the terminal penetrating through a through hole faces challenges with insufficient solder supply on one side due to inadequate heating, leading to metal exposure, while excessive heating can cause board burning.

Innovation Solution

A preliminary solder is formed on the side opposite to the solder supply position before the soldering process, which is melted and spread to cover the land portion, increasing heating capacity and preventing metal exposure and board burning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If heating by laser and iron is increased to supply solder material sufficiently to the opposite portion of the land portion, then the solder material is sufficiently supplied, but the board is easy to be burnt by the excessive temperature increase of the land portion

Engineering Contradiction:

Improvesolder material supplyVSAvoidboard burning

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

A preliminary solder is formed on the land portion at a position opposite to the solder supply position with respect to the through hole before the actual soldering process. This preliminary solder acts as a heat reservoir that absorbs and stores heat during the soldering process, ensuring sufficient heat supply to the opposite portion of the land portion without requiring excessive heating that would cause board burning.

Inventive Principle:

Principle #10Preliminary action

2Object-affected harmful factors

If heating by laser and iron is insufficient, then the board is protected from burning, but the solder material is not sufficiently supplied (spread) in the opposite portion of the land portion, so that the metal of the land portion is directly exposed

Engineering Contradiction:

Improveboard protection from burningVSAvoidsolder material supply

Core Design Contradiction:

Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

A preliminary solder is formed on the land portion at a position opposite to the solder supply position with respect to the through hole before the actual soldering process. This preliminary solder acts as a heat reservoir that absorbs and stores heat during the soldering process, ensuring sufficient heat supply to the opposite portion of the land portion without requiring excessive heating that would cause board burning.

Inventive Principle:

Principle #10Preliminary action

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 ensures consistent solder supply and distribution, preventing metal exposure and reducing the risk of board burning during the soldering process.

Implementation Method 1

the wire-shaped solder material sent onto the land portion is heated and melted by the irradiation of the laser to form a fillet covering the land portion with the terminal

Methodology Applied

Scientific EffectLaser heating: Laser

Implementation Method 2

the preliminary solder positioned on the side opposite to the solder supply position is melted and spread on the land portion

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS20240147621A1Method for manufacturing circuit substrate, and electronic device

Publication Date: 2024.05.02 ASTEMO LTD

AI summary

A manufacturing method of a circuit board including an annular land portion around a through hole through which a terminal that is an object of a soldering penetrates, and that is soldered on the land portion by a soldering process with a solder supply, the manufacturing method includes: previously forming a preliminary solder at a position opposite to a supply position of the solder in the land portion with respect to the through hole before the soldering process.