Dip soldering
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[edit] Definition
Dip soldering is a small-scale soldering process by which electronic components are soldered to a printed circuit board (PCB) to form an electronic assembly. The solder wets to the exposed metallic areas of the board (those not protected with solder mask), creating a reliable mechanical and electrical connection.
Dip soldering is used for both through-hole printed circuit assemblies, and surface mount. It is one of the cheapest methods to solder and is extensively used in the small scale industries of developing countries like India.
Dip soldering is the manual equivalent of automated Wave soldering. The apparatus required is just a small tank contaning molten solder. PCB with mounted components is dipped manually into the tank when the molten solder sticks to the exposed metallic areas of the board.
[edit] Dip solder process
Dip Soldering is derived from the Latin word, solidare, meaning to make solid.
Dip soldering (DS) is accomplished by submerging parts to be joined into a molten solder bath. Thus, all components surfaces are coated with filler metal. Solders have low surface tension and high wetting capability. There are many types of solders, each used for different applications. Such as Lead-Silver for strength at higher than room temperature. Tin-Lead is used for General Purpose; Tin-Zinc is used for Aluminum; Cadmium-Silver is used for strength at high temperatures; Zinc-Aluminum is used for Aluminum and corrosion resistance; Tin-Silver and Tin-Bismuth is used for Electronics. Because of the toxicity of lead, lead-free solders are being developed and more widely used. The molten bath can be any suitable filler metal, but the selection is usually confined to the lower melting point elements. The most common dip soldering operations use zinc-aluminum and tin-lead solders.
[edit] Solderability
Some materials are easier to solder than others. Copper, silver, and gold are easy to solder. Iron and Nickel are a little more difficult. Titanium, magnesium, cast irons, steels, ceramics, and graphites are hard to solder. However, if they are first plated they are more easily soldered. An example of this is tin-plating. A steel sheet coated with tin so it can be soldered more easily.
[edit] Applications
Dip Soldering is used extensively in the electronics industry. However, they have a limited service use at elevated temperatures because of the low melting point of the filler metals. Soldered materials do not have much strength and are therefore not used for load-bearing. [1]
[edit] References
<Kalpakjian, Serope, and Steven R. Schmid. Manufacturing Engineering and Technology: Fifth Edition. Upper Saddle River, NJ: Pearson Education, 2006> <http://www.thefreedictionary.com/dip+solder>
