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Revision as of 18:27, 16 November 2019 editPolychromePlatypus (talk | contribs)421 edits Note use for high voltage, it’s a (very) large fraction of potting use, but an insular industry segment if you’ll pardon the pun. Refine the phrasing as regards molding which was slightly misleading. The existence of “shielding and thermal dissipation” enhancement is a doubtful claim from a potting supplier, these are almost universally plastic to match the expansion/shrinkage of the material but I left it intact because potting was used though the 1960’s directly inside sheet steel casings a...Tags: Mobile edit Mobile web edit← Previous edit Revision as of 14:26, 27 November 2019 edit undoDocWatson42 (talk | contribs)Extended confirmed users, Pending changes reviewers217,659 edits Performed minor cleanup on spaces.Tags: Mobile edit Mobile web edit Advanced mobile editNext edit →
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] potted in epoxy. The surface visible on the right is formed by the potting compound that has been poured into the plastic box]] ] potted in epoxy. The surface visible on the right is formed by the potting compound that has been poured into the plastic box]]


In ], '''potting''' is a process of filling a complete electronic assembly with a solid or gelatinous compound for high voltage assemblies by excluding gaseous phenomena such as corona discharge, for resistance to shock and vibration, and for the exclusion of water, moisture, or corrosive agents. ] plastics or silicone rubber gels are often used, though ] resins are also very common.<ref name="Panda2016">{{cite book|author=Dr. H. Panda|title=Epoxy Resins Technology Handbook (Manufacturing Process, Synthesis, Epoxy Resin Adhesives and Epoxy Coatings): Manufacturing Process of Epoxy Resins, Manufacturing Process of Epoxy Resins, Making of Epoxy Resins, Process for Manufacture of Epoxy Resins, Epoxy Resin Manufacturing Plant, Epoxy Resin Plant, Epoxy Resin Production Plant, Epoxy Resin Manufacture, Epoxy Resin Manufacturing Unit, Epoxy Resin Production, Epoxy Resins in Industry, Manufacture of Epoxy Resins,|url=https://books.google.com/books?id=D0gtDQAAQBAJ&pg=PA419|date=8 July 2016|publisher=ASIA PACIFIC BUSINESS PRESS Inc.|isbn=978-81-7833-174-4|page=419}}</ref> Many sites recommend using a potting product to protect sensitive electronic components from impact, vibration, and loose wires. <ref>{{cite web|url=http://hackaday.com/2012/06/04/potting-electronics-with-silicone/ |title=Hackaday |publisher=Hackaday |date=2012-06-04 |accessdate=2018-09-04}}</ref> In ], '''potting''' is a process of filling a complete electronic assembly with a solid or gelatinous compound for high voltage assemblies by excluding gaseous phenomena such as corona discharge, for resistance to shock and vibration, and for the exclusion of water, moisture, or corrosive agents. ] plastics or silicone rubber gels are often used, though ] resins are also very common.<ref name="Panda2016">{{cite book|author=Dr. H. Panda|title=Epoxy Resins Technology Handbook (Manufacturing Process, Synthesis, Epoxy Resin Adhesives and Epoxy Coatings): Manufacturing Process of Epoxy Resins, Manufacturing Process of Epoxy Resins, Making of Epoxy Resins, Process for Manufacture of Epoxy Resins, Epoxy Resin Manufacturing Plant, Epoxy Resin Plant, Epoxy Resin Production Plant, Epoxy Resin Manufacture, Epoxy Resin Manufacturing Unit, Epoxy Resin Production, Epoxy Resins in Industry, Manufacture of Epoxy Resins,|url=https://books.google.com/books?id=D0gtDQAAQBAJ&pg=PA419|date=8 July 2016|publisher=ASIA PACIFIC BUSINESS PRESS Inc.|isbn=978-81-7833-174-4|page=419}}</ref> Many sites recommend using a potting product to protect sensitive electronic components from impact, vibration, and loose wires.<ref>{{cite web |url=http://hackaday.com/2012/06/04/potting-electronics-with-silicone/ |title=Hackaday |publisher=Hackaday |date=2012-06-04 |accessdate=2018-09-04}}</ref>


In the potting process, an electronic assembly is placed inside a mold (i.e. the "pot"<ref>{{cite web|url=https://blog.paryleneconformalcoating.com/whats-the-difference-between-potting-and-conformal-coating|title=What’s the Difference Between Potting and Conformal Coating?|date=2016-01-22|accessdate=2019-02-05}}</ref>) which is then filled with an insulating liquid compound that hardens, permanently protecting the assembly. The mold may be part of the finished article and may provide shielding or heat dissipating functions in addition to acting as a mold. When the mold is removed the potted assembly is described as cast. <ref> Haleh Ardebili, Michael Pecht, ''Encapsulation Technologies for Electronic Applications'', William Andrew, 2009 {{ISBN|0815519702}}, page 36 </ref> In the potting process, an electronic assembly is placed inside a mold (i.e. the "pot"<ref>{{cite web|url=https://blog.paryleneconformalcoating.com/whats-the-difference-between-potting-and-conformal-coating|title=What’s the Difference Between Potting and Conformal Coating?|date=2016-01-22|accessdate=2019-02-05}}</ref>) which is then filled with an insulating liquid compound that hardens, permanently protecting the assembly. The mold may be part of the finished article and may provide shielding or heat dissipating functions in addition to acting as a mold. When the mold is removed the potted assembly is described as cast.<ref>Haleh Ardebili, Michael Pecht, ''Encapsulation Technologies for Electronic Applications'', William Andrew, 2009 {{ISBN|0815519702}}, page 36</ref>


As an alternative, many circuit board assembly houses coat assemblies with a layer of transparent ] rather than potting.<ref>{{cite web|url=http://ww1.microchip.com/downloads/en/AppNotes/01288A.pdf |title=Design Practices for Low-Power External Oscillators |format=PDF |date= |accessdate=2018-09-04}}</ref> Conformal coating gives most of the benefits of potting, and is lighter and easier to inspect, test, and repair. Conformal coatings can be applied as liquid or condensed from a vapor phase. As an alternative, many circuit board assembly houses coat assemblies with a layer of transparent ] rather than potting.<ref>{{cite web|url=http://ww1.microchip.com/downloads/en/AppNotes/01288A.pdf |title=Design Practices for Low-Power External Oscillators |format=PDF |date= |accessdate=2018-09-04}}</ref> Conformal coating gives most of the benefits of potting, and is lighter and easier to inspect, test, and repair. Conformal coatings can be applied as liquid or condensed from a vapor phase.


When potting a circuit board that uses ], low ] (T<sub>g</sub>) potting compounds such as ] or ] may be used, because high T<sub>g</sub> potting compounds may break solder bonds through ] because by hardening at a higher temperature the coating then shrinks as a rigid solid over a larger part of the temperature range thus developing greater force. <ref>{{cite web|url=http://www.pottingsolutions.com/my%20site/Technology/potting_hints.htm#Potting%20PC%20boards |title=Potting Solutions Potting Hints |publisher=Pottingsolutions.com |date=2015-03-28 |accessdate=2018-09-04}}</ref> When potting a circuit board that uses ], low ] (T<sub>g</sub>) potting compounds such as ] or ] may be used, because high T<sub>g</sub> potting compounds may break solder bonds through ] because by hardening at a higher temperature the coating then shrinks as a rigid solid over a larger part of the temperature range thus developing greater force.<ref>{{cite web|url=http://www.pottingsolutions.com/my%20site/Technology/potting_hints.htm#Potting%20PC%20boards |title=Potting Solutions Potting Hints |publisher=Pottingsolutions.com |date=2015-03-28 |accessdate=2018-09-04}}</ref>


==See also== ==See also==

Revision as of 14:26, 27 November 2019

A small transformer potted in epoxy. The surface visible on the right is formed by the potting compound that has been poured into the plastic box

In electronics, potting is a process of filling a complete electronic assembly with a solid or gelatinous compound for high voltage assemblies by excluding gaseous phenomena such as corona discharge, for resistance to shock and vibration, and for the exclusion of water, moisture, or corrosive agents. Thermosetting plastics or silicone rubber gels are often used, though epoxy resins are also very common. Many sites recommend using a potting product to protect sensitive electronic components from impact, vibration, and loose wires.

In the potting process, an electronic assembly is placed inside a mold (i.e. the "pot") which is then filled with an insulating liquid compound that hardens, permanently protecting the assembly. The mold may be part of the finished article and may provide shielding or heat dissipating functions in addition to acting as a mold. When the mold is removed the potted assembly is described as cast.

As an alternative, many circuit board assembly houses coat assemblies with a layer of transparent conformal coating rather than potting. Conformal coating gives most of the benefits of potting, and is lighter and easier to inspect, test, and repair. Conformal coatings can be applied as liquid or condensed from a vapor phase.

When potting a circuit board that uses surface-mount technology, low glass transition temperature (Tg) potting compounds such as polyurethane or silicone may be used, because high Tg potting compounds may break solder bonds through solder fatigue because by hardening at a higher temperature the coating then shrinks as a rigid solid over a larger part of the temperature range thus developing greater force.

See also

References

  1. Dr. H. Panda (8 July 2016). Epoxy Resins Technology Handbook (Manufacturing Process, Synthesis, Epoxy Resin Adhesives and Epoxy Coatings): Manufacturing Process of Epoxy Resins, Manufacturing Process of Epoxy Resins, Making of Epoxy Resins, Process for Manufacture of Epoxy Resins, Epoxy Resin Manufacturing Plant, Epoxy Resin Plant, Epoxy Resin Production Plant, Epoxy Resin Manufacture, Epoxy Resin Manufacturing Unit, Epoxy Resin Production, Epoxy Resins in Industry, Manufacture of Epoxy Resins,. ASIA PACIFIC BUSINESS PRESS Inc. p. 419. ISBN 978-81-7833-174-4.
  2. "Hackaday". Hackaday. 2012-06-04. Retrieved 2018-09-04.
  3. "What's the Difference Between Potting and Conformal Coating?". 2016-01-22. Retrieved 2019-02-05.
  4. Haleh Ardebili, Michael Pecht, Encapsulation Technologies for Electronic Applications, William Andrew, 2009 ISBN 0815519702, page 36
  5. "Design Practices for Low-Power External Oscillators" (PDF). Retrieved 2018-09-04.
  6. "Potting Solutions Potting Hints". Pottingsolutions.com. 2015-03-28. Retrieved 2018-09-04.

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