Selective soldering

Selective soldering

Selective soldering is the process of selectively soldering components to printed circuit boards, molded modules, etc. that could be damaged by the heat of a reflow oven in a traditional SMT assembly process. Consequently this process usually follows an SMT oven reflow process, but not always. Therefore parts to be selectively soldered are most often surrounded by parts that have been previously soldered in a surface mount reflow process, and the selective solder process must be sufficiently precise in order to avoid these components so as not to damage them.


There is a number of assembly processes used to perform selective soldering; these include:

# Selective aperture tooling over wave solder. These tools effectively mask off the areas previously soldered in the SMT reflow soldering process while exposing only those areas to be selectively soldered in the apertures of the tool. The tool/PCB assembly is then passed over traditional wave soldering equipment to complete the process. Each tool is specific to a PCB assembly.
# Mass-Selective-Dip-Solder fountain, is the analog of selective aperture, whereby specialized tooling with apertures to allow solder to be pumped through it represent the areas to be soldered. The PCB is then presented over the selective solder fountain and all selective soldering of the printed circuit board are soldered simultaneously as the PCB is lowered into the solder fountain. Each tool is specific to a PCB assembly.
# Miniature wave selective solder fountain(s) typically use a miniature pumped solder wave with a spherical shape similar to the end of a pencil or Crayola to sequentially solder the PCB. This process is somewhat slower than the two previous methods, but much more accurate. The PCB may be fixed and the wave/wave solder pot moved underneath the PCB In 3-axis, or alternately the PCB may be articulated over a fixed wave/solder bath to perform the selective solder process. This process is generally regarded to be tool-less unlike to the first two examples.
# Laser Selective Soldering System are the newest systems and are able to import CAD-based board layouts and use that data to position a laser to directly solder any point on the board. The major benefits are thermal stress is eliminated, non-contact soldering process, consistent high quality solder joints, and maximum flexibility. Solder time can typically average 1 sec per solder joint. It may even be possible to eliminate stencils and solder masks from the circuit board to reduce manufacturing costs.
# Other less common selective solder processes include
#* hot-iron solder with wire-solder feed
#* induction solder with paste-solder, solder-laden pads, or pre-forms and, hot-gas including hydrogen with various methods of presenting the solder as above.

There are other selective solder applications that can be considered, some of which are non-electronic such as lead-frame attachment to ceramic substrates, coil-lead attachment, SMT attachment such as LED's to PCB's, fire sprinklers where the fuse is low temperature solder alloys and many more.

External links

* [ Different solutions for the selective soldering] video and explanation how to solder or desolder

Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Soldering — For the song, see Soldering (song). For the product, see Solder. Desoldering a contact from a wire. Soldering is a process in which two or more metal items are joined together by melting and flowing a filler metal (solder) into the joint, the… …   Wikipedia

  • selective dip soldering — atrankusis merkiamasis litavimas statusas T sritis radioelektronika atitikmenys: angl. selective dip soldering vok. selektive Tauchlötung, f rus. избирательная пайка погружением, f pranc. soudage sélectif par immersion, m …   Radioelektronikos terminų žodynas

  • Electronics manufacturing — This article presents a typical manufacturing process of an electronic assembly.Component manufacturingComponents such as resistors, capacitors and integrated circuits are generally made by specialized contractors. Integrated circuits are… …   Wikipedia

  • Hot-bar reflow — is a selective soldering process where two pre fluxed, solder coated parts are heated with heating element (called a thermode) to a sufficient temperature to melt the solder.Pressure is applied through the whole process (usually 15 s) to insure… …   Wikipedia

  • Brazing — This article is about the metal joining process. For the cooking technique, see braising. Brazing practice Brazing is a metal joining process whereby a filler metal is heated above and distributed between two or more close fitting parts by… …   Wikipedia

  • Gold plating — is a method of depositing a thin layer of gold onto the surface of another metal, most often copper or silver, by chemical or electrochemical means.Mechanical or chemical affixing of thin gold foils onto the surface of objects is instead known as …   Wikipedia

  • metalwork — metalworker, n. /met l werrk /, n. objects made of metal. [1840 50; METAL + WORK] * * * Useful and decorative objects fashioned of various metals. The oldest technique is hammering. After с 2500 BC, casting was also used, molten metal being… …   Universalium

  • metallurgy — metallurgic, metallurgical, adj. metallurgically, adv. metallurgist /met l err jist/ or, esp. Brit., /meuh tal euhr jist/, n. /met l err jee/ or, esp. Brit., /meuh tal euhr jee/, n. 1. the technique or science of working or heating metals so as… …   Universalium

  • arts, East Asian — Introduction       music and visual and performing arts of China, Korea, and Japan. The literatures of these countries are covered in the articles Chinese literature, Korean literature, and Japanese literature.       Some studies of East Asia… …   Universalium

  • Palladium — (pronounced pəˈleɪdiəm) is a rare and lustrous silvery white metal that was discovered in 1803 by William Hyde Wollaston, who named it palladium after the asteroid Pallas, which in turn, was named after the epithet of the Greek goddess Athena,… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”