1. Making it at home

2. What is a PCB ?  A PCB contains a fiber glass epoxy board with thin copper layers attached to it.  A photographic process is used to etch off the copper where it is not needed to connect ICs.  Prior to etching, all holes are drilled in the PCB and it is electroplated so that the feed through holes connect to the different copper layers.  Electronic parts are soldered to copper mounting pads left after etching, and thin copper traces are used to connect the parts.

3. More on PCBs  The designer must use a PCB layout CAD tool to design the pads and interconnect lines.  The PCB layout tool produces the artwork for the photographic mask that is used to chemically etch the PCB.  Small simple boards have two copper layers.  Boards like PC motherboards are very complex and have 8-12 stacked layers of copper (more expensive setup charge – too high for student projects!)

4. Why we need PCB?  No wires  Makes a design permanent  In industrial scale production of circuits

5. Steps in making a PCB  Design schematic  Design layout  Fabricate the layout

6. Parts / Components  Electronic components Schematic symbol Description (used for BOM) Footprint (Simulation model)

7. Footprint examples:  DIP16  SOT23

8. Footprint examples:  SOIC8  PQFP240

9. Footprint examples:  FineLine BGA484  BGA256  TSOP48

10. Schematic capture

11. Export schematic to PCB

12. Place components on PCB

13.  Distance from pad to trace > 10 mil

14. Distance between components > 10 mil

15. PCB making softwares  Autocrat EDA  EAGLE  FreePCB (open-source Win2K/XP)  FreeRouting  Cadstar  Electronics Workbench  gEDA, open-source PCB software project  OrCAD  Allegro (Cadence)  PADS  Dip Trace

16. Dip Trace – Draw the Schematichttp://www.diptrace.com/ Diptrace has a Free Version: Freeware edition does not support export to DXF, Gerber and N/C Drill, max. number of pins — 250.

17. PCB Rapid Prototyping Systems  CNC machine mills out copper traces with small cutting tools and drills  OK for small quantity simple boards  Interfaces to PCB design software files

19. Methods of etching  Silk screen printing uses etch-resistant inks to protect the copper foil. Subsequent etching removes the unwanted copper. Alternatively, the ink may be conductive, printed on a blank (non-conductive) board. The latter technique is also used in the manufacture of hybrid circuits. Silk screen printinghybrid circuits  Photoengraving uses a photomask and chemical etching to remove the copper foil from the substrate. The photomask is usually prepared with a photoplotter from data produced by a technician using CAM, or computer-aided manufacturing software. Laser-printed transparencies are typically employed for phototools; however, direct laser imaging techniques are being employed to replace phototools for high-resolution requirements. Photoengravingphotoplottercomputer-aided manufacturing  PCB milling uses a two or three-axis mechanical milling system to mill away the copper foil from the substrate. A PCB milling machine (referred to as a 'PCB Prototyper') operates in a similar way to a plotter, receiving commands from the host software that control the position of the milling head in the x, y, and (if relevant) z axis. Data to drive the Prototyper is extracted from files generated in PCB design software and stored in HPGL or Gerber file format. PCB millingplotterHPGLGerber

20. Toner Transfer Method A method of creating a printed circuit board (PCB) using a copy machine or a laser printer to make apply the etchant resist pattern Software now available to create schematic and PCB layout No expensive equipment is required but can be helpful in the home A simple process once the basics are mastered

21. Print to Transfer Paper

22. Transfer Toner to Board

23. Remove Paper from Toner Soak 20+ Min. Warm, Soapy Water

24. Rub off the paper

25. Circuit Ready for Etching

26. Wash off the unwanted copper

27. Laser Printer  Toner is plastic based

28. Soldering

29. Troubleshooting

30. References  http://www.kpsec.freeuk.com/solder.htm  http://ezinearticles.com/?The-3-Different-Types-of-Printed-Circuit-Boards&id=3133963  http://en.wikipedia.org/wiki/Printed_circuit_board  http://www.qsl.net/vk5cu/  http://bot-thoughts.blogspot.com/2009/08/simple-diy-pcb-etching.html  http://www.kpsec.freeuk.com/boards.htm  http://www.diptrace.com/books/  http://www.youtube.com/watch?v=urv6jArKp6M  http://gilmore2.chem.northwestern.edu/projects/garbz2_prj.php

31. Thank You