Soldering Problems

Defect- A defect in soldering is generally a non-conformance to standards, requirements or expectations for a certain soldering task. Common soldering defects include solder balls, solder beads, lifted pads, insufficient wetting, solder starving, excess solder, solder bridges and apple solder connections. These all result from different factors and have varied solutions.

Desoldering- This is basically the reverse of soldering and involves removing dried-up solder from a soldered work-piece. For this, one needs a soldering iron kit, desoldering braid or a solder sucker depending on the preferred method. Other brutal methods include use of heat guns, air guns and air compressors.

Double sided PCB- A double sided printed circuit board is basically a rigid board containing a substrate, solder mask, silk screen and mostly copper. The board is used to provide electrical point to point connections for components that work together in a system. Circuit boards can be found in a wide range of electronics. However, unlike regular PCBs, the double sided variety has an electrical conducting pattern on both sides of the board.

Dry solder joint- In soldering, a dry or solder-starved joint is the point of a bond formed by molten solder that did not receive as much solder as required. Solder starved joints can be caused by a wide range of factors including incorrect soldering temperatures, poor contact between the solder and iron tip and use of poor quality solder. A solder-starved joint often develops cracks with time, forms poor bonding of components and is thus generally unreliable as a contact point especially in soldered electrical components. There are however easy solutions to these problems.

Dwell time- This is the entire period of time when contact takes place between a heat source and a workspace. Once the heat source is removed or cut off, the dwell time ends.

Soldering Dictionary

Mini-wave soldering- This is an improvement to wave soldering. However, it makes use of the controlled collapse technique coupled with external flux and high surface tension for soldering. It is basically used to install components that have multiple leads onto PCBs. The method allows soldering of a large number of SMDs simultaneously.

Mealing- This is a defect that manifests itself in the form of little spots and points to separation in the layers composed of coatings and the substrate or base material of a printed circuit board. This separation could also be between the coating, substrate and a component.

Micro ball grid array- This is a variation of the surface mount soldering technique. Like CCGA, the components soldered onto printed circuit boards under this method have no leads but instead make use of tiny solder balls or solder columns for support, heat sinking and electrical conductivity. The solder is usually reflowed using CCS (Controlled Collapse Soldering).

Meniscograph- This is an advanced soldering tool that measures the solderability a material. The instrument makes use of what is commonly known as the wetting balance method. This basically measures the duration of time between buoyancy to when the wetting pull occurs.

Minimum electrical spacing- This is the smallest allowable distance between two or more adjacent electrical conducting patterns, components or points. This is usually calculated depending on the operating voltage and serves as a preventive measure against corona and the effects of a dielectric breakdown.

Minor and major burns- These are injuries caused when the body comes into contact with an extreme heat source. Burns should be gently soothed. This is the first step in dealing with minor burns and often involves the use of a dampened cloth or cool running water. These should then be immediately addressed to a medical expert.

 

Soldering Jargon II

Excess solder- Excess solder occurs when too much solder is applied on a component lead or pad or both. This usually results in an almost spherical ball of solder. The downside to excess solder is that in most instances, wetting is very poor with the lead and pad and may therefore lead to a very poor electrical connection.

Eutectic solder- This is a general term that describes a solder alloy that does not have what is known as a plastic range. Examples of these include the common tin-lead solder. There are however two specific varieties of this solder that are eutectic, namely Sn63/Pb37 and Sn96/Pb4. The numbers signify the proportion of each metal in a 100 percent of the alloy.

Fahrenheit- A common temperature scale used in soldering and related activities. Under this scale, the freezing point of water is 32degrees Fahrenheit and its boiling point is 212 degrees Fahrenheit. The scale is however relatively less used that the centigrade scale which is the more popular one.

FPT- Stands for fine pitch technology. It is a relatively modern variation of the surface mount technique. Under FPT, the components have leads on surfaces that measure less than 0.625 millimeters. This figure however continues to reduce with each passing day.

Flux- In soldering, flux is an agent that can serve various purposes such as cleaning, purifying, dissolving metal oxides and acting as a reducing agent that undoes the effects of oxidization. Basically, at room temperatures, most kinds of flux are inert. This however changes once the flux is exposed to high temperature levels. Once heated, flux becomes an active reducing agent and thus prevents the oxidization of metals into their respective metal oxides. This is necessary since the commonly used types of solder rarely attach to oxidized metals.