#solderability

[cylexplastics]

FR4 Surface Treatment Technologies: Anti-Oxidation and Enhanced Solderability

In PCB manufacturing, proper FR4 surface treatment is crucial for both protecting copper traces from oxidation and ensuring reliable solder joints. This article explores the most effective surface finishing techniques used in the electronics industry today. Why FR4 Surface Treatment Matters FR4, the most common PCB substrate material, features copper traces that are vulnerable to oxidation when…

FR4 Surface Treatment Technologies: Anti-Oxidation and Enhanced Solderability

[tereske-blog]

Factors affecting your soldering results: Thermal mass and linkage

Each joint with a soldering pad has its own thermal mass. This is its unique ability to absorb and to store heat energy. The thermal mass of an element determines how much heat is needed to solder it and for how long the item will be exposed to that level of heat. Thermal linkage on the other hand refers to the surface area forming the points of contact between the soldering iron tip and the lead. A very small thermal linkage causes insufficient flow of solder and thus structurally-weak joints.

The above-mentioned factors determine to a great extent the outcome of a soldering task. If excess heat is applies to material with low thermal mass, it almost certainly melts the item and causes an overheated joint. On the other hand, if less than sufficient heat is applied to material with high thermal mass, the end result will be a solder-starved joint or a cold joint. It is therefore important to understand the thermal mass of the solder and the workspace.

Thermal linkage on the other hand has a direct effect on the amount of solder that will flow to the joint. A very wide linkage will cause an excessively soldered joint while a very small linkage will cause a solder-starved joint. The balance therefore lies in having just the right surface contact of thermal linkage to ensure sufficient flow of solder. Thermal linkage is influenced by factors such as the size of the tip, size of the component lead, iron handling technique and the skill of the artist. For very small or very large components however, it becomes very difficult to have sufficient linkage with an average soldering iron.

[megandsta-blog]

Factors affecting your soldering results: Surface condition

For this description, the surface condition refers to the surface of the printed circuit board. However, you will not always be working on PCBs. Most of the steps though are applicable to all types of surfaces. A working surface may influence the outcome of soldering results in various ways through its resist flow, cleanliness and spacing of components.

Resist flow

This is the attribute of a soldering surface that prevents the flow of solder to unintended areas. Surfaces with good resist flow are able to maintain solder at the point of contact until it cools. If a surface has poor resist flow, the solder will flow and cool into solder balls which are some of the defects associated with incorrect soldering. The material making up a surface is the main factor determining the resist flow of the board.

Cleanliness

Metals, metal oxides, solder and flux attach very poorly to dirty surfaces. This implies that for you to achieve the best results, it is important to clean the surface and rid it of many impurities as possible. Dirty surfaces cause insufficient wetting and therefore produce poor and weak joints that develop cracks with time.

Component spacing

The distance between components on a PCB determines the possibility of formation of solder beads. Solder beads are related to solder balls. However a solder bead refers to a group of solder balls that form closely together and thus resemble a bead. Solder beads often occur close to the components that were being soldered. Just how to solder beads form? The formation of solder beads is usually supported by the application of too much solder paste or the limited distance across two components. A well-spaced surface allows for good flow of solder paste and flux without forming solder bridges.