ece projects lab surface mount technology. what is smt? surface mount technology used primarily in...
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ECE Projects LabECE Projects Lab
Surface Mount TechnologySurface Mount Technology
What is SMT?What is SMT?
Surface Mount TechnologySurface Mount Technology
Used primarily in industryUsed primarily in industry
Same circuitry with much smaller Same circuitry with much smaller componentscomponents
Was not intended for individual soldering, Was not intended for individual soldering, but gaining popularitybut gaining popularity
SMT ComponentsSMT Components
““Reflow”Reflow”a thermal process in which solder paste is a thermal process in which solder paste is used to electrically connect components to used to electrically connect components to their attachment pads. It is the most their attachment pads. It is the most common means to attach a surface common means to attach a surface mounted component to a circuit boardmounted component to a circuit board
““Reflow temperature” is the temperature at Reflow temperature” is the temperature at which the solder paste changes state from which the solder paste changes state from solid to liquidsolid to liquid
SMT BoardSMT Board
Why SMT (advantages)?Why SMT (advantages)?
Much smaller sizeMuch smaller size
Components on both sides of boardComponents on both sides of board
Leads can be much shorter reducing Leads can be much shorter reducing inductance and resistance thereby inductance and resistance thereby increasing performanceincreasing performance
Prototyping is more indicative of the final Prototyping is more indicative of the final productproduct
How to SMT solder (techniques)How to SMT solder (techniques)
Fine tip solderingFine tip soldering– Uses conventional soldering techniques on a Uses conventional soldering techniques on a
much smaller scalemuch smaller scale
Hot plate reflowHot plate reflow– Useful for single ICs with limited footprintUseful for single ICs with limited footprint
Oven reflowOven reflow– Uses soldering paste and reflows entire boardUses soldering paste and reflows entire board
How to SMT reworkHow to SMT rework
Solder wickSolder wick– Uses fine mesh conductive Copper braid. Uses fine mesh conductive Copper braid.
Heat and capillary action pulls excess solder Heat and capillary action pulls excess solder awayaway
Hot air reflowHot air reflow– Uses hot air to reflow the solder with Uses hot air to reflow the solder with
components presentcomponents present
De-Solder vacuum plunger/suckerDe-Solder vacuum plunger/sucker– Uses small negative pressure to suck up Uses small negative pressure to suck up
excess solderexcess solder
Fine Tip SolderingFine Tip SolderingConventional EquipmentConventional Equipment
Useful for Larger Useful for Larger componentscomponents
Causes eye strainCauses eye strain
Requires a steady Requires a steady handhand
Fine Tip SolderingFine Tip SolderingSpecialized Fine-tip toolsSpecialized Fine-tip tools
Hot-Air Rework Hot-Air Rework Station AM6500 by Station AM6500 by JBCJBC– Fine tip solder toolsFine tip solder tools– Desoldering toolsDesoldering tools– Hot tweezersHot tweezers– Hot air gunHot air gun
Hot plate reflowHot plate reflow
useful for smaller useful for smaller boards as heat boards as heat distribution on a distribution on a hotplate is far less hotplate is far less uniform than a uniform than a convection ovenconvection oven
end point is end point is monitored visuallymonitored visually
Oven reflowOven reflow
Typical Reflow ovenTypical Reflow oven– Large and bulkyLarge and bulky– Expensive $$$ Expensive $$$
Cuisinart TOB 165– Just as good– A small fraction of the
cost
Oven Reflow OverviewOven Reflow Overview
After applying solder After applying solder paste and setting paste and setting components, the components, the board is inserted to board is inserted to be “cooked”be “cooked”
End result is a End result is a perfectly soldered perfectly soldered board for a fraction of board for a fraction of the cost (no eye strain the cost (no eye strain either)either)
Reflow ProfileReflow Profile
The temperature of The temperature of the reflow process the reflow process must:must:– be precise enough to be precise enough to
not damage IC’s not damage IC’s through excess heatthrough excess heat
– be sufficient for reflow be sufficient for reflow of solderof solder
Oven Reflow StepsOven Reflow Steps Apply soldering pasteApply soldering paste Set IC’s and componentsSet IC’s and components
Cook!Cook! Touch up (here using solder wick)Touch up (here using solder wick)
Industrial SMT MovieIndustrial SMT Movie
Silicon Run IISilicon Run II
Copper Solder Wick (rework)Copper Solder Wick (rework)
useful for removing useful for removing excess solderexcess solder
braided copper mesh is braided copper mesh is used to remove solder used to remove solder via capillary actionvia capillary action
Fine-tip or conventional Fine-tip or conventional soldering iron is used for soldering iron is used for heating braid and solderheating braid and solder
Hot air reflow (rework)Hot air reflow (rework)
Hot-Air Rework Hot-Air Rework Station AM6500 by Station AM6500 by JBCJBC– Fine tip solder toolsFine tip solder tools– Desoldering toolsDesoldering tools– Hot tweezersHot tweezers– Hot air gunHot air gun
How hot air reflow worksHow hot air reflow works
Hot air used to Hot air used to desolder ICdesolder IC
Vacuum extractor Vacuum extractor pulls IC after solder pulls IC after solder flowsflows
De-Solder vacuum plunger/suckerDe-Solder vacuum plunger/sucker(rework)(rework)
Uses small vacuum Uses small vacuum to pull solder away to pull solder away from boardfrom boardHand-held manual Hand-held manual versionversionHeated tip & Heated tip & vacuum combined vacuum combined on SMT rework on SMT rework stationstation
SummarySummary
Fine tip soldering is hard, but essential Fine tip soldering is hard, but essential sometimessometimes
Hotplate or Oven reflow are great for Hotplate or Oven reflow are great for creating a whole board at oncecreating a whole board at once
Rework techniques include Copper wick, Rework techniques include Copper wick, Hot-air reflow, and de-solder vacuumingHot-air reflow, and de-solder vacuuming
ECE Projects Lab can do it allECE Projects Lab can do it all
Credits/Work citedCredits/Work cited
http://en.wikipedia.org/wiki/Surface-mount_technologyhttp://en.wikipedia.org/wiki/Surface-mount_technology– General SMT infoGeneral SMT info
http://www.heinc.com/jbc/repair.htmlhttp://www.heinc.com/jbc/repair.html– Hot air reflow station websiteHot air reflow station website
http://www.bidservice.com/Browses/http://www.bidservice.com/Browses/NF_Detailed_Item_View_new.asp?ProductID=20069NF_Detailed_Item_View_new.asp?ProductID=20069– Place to purchase typical reflow ovenPlace to purchase typical reflow oven
http://www.seattlerobotics.org/encoder/200006/oven_art.htmhttp://www.seattlerobotics.org/encoder/200006/oven_art.htm– Another group that has done a similar project with a toaster ovenAnother group that has done a similar project with a toaster oven
http://www.circuitcellar.com/library/print/0704/Lacoste_168/http://www.circuitcellar.com/library/print/0704/Lacoste_168/– Thermal profile for a toaster ovenThermal profile for a toaster oven
Design Lab WebsiteDesign Lab Website
Presentations availablePresentations available
Online Reflow TutorialOnline Reflow Tutorial
http://www.ee.duke.edu/DesignLab/http://www.ee.duke.edu/DesignLab/
Thanks!Thanks!