1. Surface Mount Technology
ECE Projects Lab
Surface Mount Technology

2. What is SMT? Surface Mount Technology Used primarily in industry
Same circuitry with much smaller components
Was not intended for individual soldering, but gaining popularity
SMT has been around in industry since the late 80’s. After the prevalent use of dip chips on

3. SMT Components

4. “Reflow”
a thermal process in which solder paste is used to electrically connect components to their attachment pads. It is the most common means to attach a surface mounted component to a circuit board
“Reflow temperature” is the temperature at which the solder paste changes state from solid to liquid

5. SMT Board

6. Why SMT (advantages)? Much smaller size
Components on both sides of board
Leads can be much shorter reducing inductance and resistance thereby increasing performance
Prototyping is more indicative of the final product

7. How to SMT solder (techniques)
Fine tip soldering
Uses conventional soldering techniques on a much smaller scale
Hot plate reflow
Useful for single ICs with limited footprint
Oven reflow
Uses soldering paste and reflows entire board

8. How to SMT rework Solder wick Hot air reflow
Uses fine mesh conductive Copper braid. Heat and capillary action pulls excess solder away
Hot air reflow
Uses hot air to reflow the solder with components present
De-Solder vacuum plunger/sucker
Uses small negative pressure to suck up excess solder

9. Fine Tip Soldering Conventional Equipment
Useful for Larger components
Causes eye strain
Requires a steady hand

10. Fine Tip Soldering Specialized Fine-tip tools
Hot-Air Rework Station AM6500 by JBC
Fine tip solder tools
Desoldering tools
Hot tweezers
Hot air gun

11. Hot plate reflow
useful for smaller boards as heat distribution on a hotplate is far less uniform than a convection oven
end point is monitored visually

12. Oven reflow Typical Reflow oven Cuisinart TOB 165 Large and bulky
Expensive $$$ 
Cuisinart TOB 165
Just as good
A small fraction of the cost

13. Oven Reflow Overview
After applying solder paste and setting components, the board is inserted to be “cooked”
End result is a perfectly soldered board for a fraction of the cost (no eye strain either)

14. Reflow Profile The temperature of the reflow process must:
be precise enough to not damage IC’s through excess heat
be sufficient for reflow of solder

15. Oven Reflow Steps Set IC’s and components Apply soldering paste Cook!
Touch up (here using solder wick)

16. Industrial SMT Movie
Silicon Run II

17. Copper Solder Wick (rework)
useful for removing excess solder
braided copper mesh is used to remove solder via capillary action
Fine-tip or conventional soldering iron is used for heating braid and solder

18. Hot air reflow (rework)
Hot-Air Rework Station AM6500 by JBC
Fine tip solder tools
Desoldering tools
Hot tweezers
Hot air gun

19. How hot air reflow works
Hot air used to desolder IC
Vacuum extractor pulls IC after solder flows

20. De-Solder vacuum plunger/sucker (rework)
Uses small vacuum to pull solder away from board
Hand-held manual version
Heated tip & vacuum combined on SMT rework station

21. Summary Fine tip soldering is hard, but essential sometimes
Hotplate or Oven reflow are great for creating a whole board at once
Rework techniques include Copper wick, Hot-air reflow, and de-solder vacuuming
ECE Projects Lab can do it all

22. Credits/Work cited
General SMT info
Hot air reflow station website
Place to purchase typical reflow oven
Another group that has done a similar project with a toaster oven
Thermal profile for a toaster oven

23. Design Lab Website Presentations available Online Reflow Tutorial

24. Thanks!