Bonus Unit: Surface Mount Devices & Printed Circuit Boards

|| Surface mounting was originally called "planar mounting".[1]

Surface-mount technology was developed in the 1960s and became widely used in the mid 1980s. By the late 1990s, the great majority of high-tech electronic printed circuit assemblies were dominated by surface mount devices. Much of the pioneering work in this technology was done by IBM. The design approach first demonstrated by IBM in 1960 in a small-scale computer was later applied in the Launch Vehicle Digital Computer used in the Instrument Unit that guided all Saturn IB and Saturn V vehicles.[2] Components were mechanically redesigned to have small metal tabs or end caps that could be directly soldered to the surface of the PCB. Components became much smaller and component placement on both sides of a board became far more common with surface mounting than through-hole mounting, allowing much higher circuit densities and smaller circuit boards and, in turn, machines or subassemblies containing the boards.

Often only the solder joints hold the parts to the board; in rare cases parts on the bottom or "second" side of the board may be secured with a dot of adhesive to keep components from dropping off inside reflow ovens if the part has a large size or weight.[citation needed] Adhesive is sometimes used to hold SMT components on the bottom side of a board if a wave soldering process is used to solder both SMT and through-hole components simultaneously. Alternatively, SMT and through-hole components can be soldered on the same side of a board without adhesive if the SMT parts are first reflow-soldered, then a selective solder mask is used to prevent the solder holding those parts in place from reflowing and the parts floating away during wave soldering. Surface mounting lends itself well to a high degree of automation, reducing labor cost and greatly increasing production rates. || --Wikipedia page on Surface Mount Technology, taken 7/24/2020

Many Updates Pending on this page

Here: https://gitlab.cba.mit.edu/pub/circuits

Bonus Unit =====

Surface Mount & Tabletop CNC Laser cut/ Chemically Etched circuits

  • Lesson:

    • compare/ contrast surface mount and through hole

    • Discuss advantages of surface mount

    • Outline process of milling a PCB from FR4 on Shapeoko (or other mill)

      1. KiCad or Eagle

      2. FlatCam

      3. CNC (with enough rigidity and not too much 'wobble' runout or backlash)

Fusion360, Eagle, KiCAD and Gcode

  • Lesson:

    • guided introduction to Eagle, Ki-Cad or circuit design in Fusion360

    • Process to go from design > Gcode > milling

      • On Shapeoko

      • On dedicated machines...

    • Gerber files and ordering from a Fab House

Assignment [Unit 12.2]