Flux Coating of Solder Precoated Lands to Prevent Oxidation
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Solution Overview
Problem
In the manufacturing of solder precoated substrates, residues left on the surface of the precoated area are prone to oxidation, leading to soldering defects during the subsequent electronic component soldering process.
Innovation Solution
A mounting substrate manufacturing method involving a paste disposing step, a melting and solidifying step, a breaking step to expose the precoated area, a flux disposing step, and a reflow step to solder the electronic component, minimizing exposure to air and oxidation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a cleaning step is performed to remove residues from the precoated area, then the surface quality is improved, but the precoated area is exposed to air and oxidized
Solution Approach 1:
The flux is applied to the precoated area before the residue is completely removed, creating a protective layer that prevents oxidation during the subsequent residue removal process. This preliminary action of flux application solves the contradiction by protecting the surface while maintaining cleaning effectiveness.
2Ease of manufacture
If the precoated area is exposed to air for residue removal, then cleaning is achieved, but oxidation occurs leading to soldering defects
Solution Approach 1:
The flux creates a chemically protective environment over the precoated area, effectively replacing air exposure with a protective chemical barrier. This inert environment approach prevents oxidation while allowing residue removal to proceed, thereby maintaining soldering quality.
3Manufacturing precision
If a separate residue cleaning step is added to the process, then surface quality is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The flux application step is merged with the residue removal process, combining two separate operations into one integrated step. The flux serves dual purposes: protecting the precoated area and facilitating residue removal, thereby reducing process complexity while maintaining surface quality.
Solution Approach 2:
The flux performs multiple functions simultaneously: it protects the precoated area from oxidation, facilitates residue removal, and prepares the surface for subsequent soldering. This multi-functionality eliminates the need for separate cleaning steps, reducing manufacturing complexity.
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
Reduces the occurrence of soldering defects and eliminates the need for a residue cleaning step, thereby reducing manufacturing costs.
Implementation Method 1
a melting and solidifying step of melting and solidifying the solder paste, to form a precoated area coated with solder, on the land
Implementation Method 2
a reflow step of heating the substrate to melt the precoated area, to solder the terminal to the land
Implementation Method 3
heating the substrate to melt the precoated area, to solder the terminal to the land
Implementation Method 4
a breaking step of breaking a residue covering a surface of the precoated area by pressing a tool against the precoated area
Data Source
AI summary
A mounting substrate manufacturing method for soldering a terminal of an electronic component to a land 2 of a substrate 1 includes: a paste disposing step of disposing a solder paste on the land 2; a melting and solidifying step of melting and solidifying the solder paste, to form a precoated area 3 coated with solder, on the land 2; a breaking step of breaking a residue covering a surface of the precoated area 3 by pressing a tool 432, 442 against the precoated area 3; a flux disposing step of disposing a flux F on the precoated area 3; a component placement step of placing an electronic component on the substrate 1, with the terminal of the electronic component aligned with the precoated area 3; and a reflow step of heating the substrate 1 to melt the precoated area 3, to solder the terminal to the land 2. This can provide a mounting substrate manufacturing method that can reduce the occurrence of soldering defects.