PCB DESIGN WORKSHOP for electronics engineering students.pptx

PCB workshop content

1. Workshop on PCB DESIGNING

2. What is PCB? PCB is an acronym for  printed circuit board . It is a board that has lines and pads that connect various points together.  there are traces that electrically connect the various connectors and components to each other. A PCB allows signals and power to be routed between physical devices. PCB's can be single sided (one copper layer), double sided (two copper layers) or multi-layer. A PCB populated with electronic components is called a printed circuit assembly (PCA), printed circuit board assembly or PCB assembly (PCBA)

3. History First Developed by Australian Engineer Paul Eisler Printed circuit board is the most common name but may also be called "printed wiring boards" or "printed wiring cards". Before the advent of the PCB circuits were constructed through a laborious process of point-to-point wiring. This led to frequent failures at wire junctions and short circuits when wire insulation began to age and crack.

4. Printed Wiring Boards

5. Types of PCBs There are mainly three types of PCBs Single sided PCB Double Sided Multilayer PCB

6. Single sided PCB This type of printed circuit board contains just one layer of substrate, or base material. One side of the substrate is covered with a thin layer of metal, typically copper because it’s an excellent electrical conductor. A single-sided PCB has electronic components and circuits on only one side. This type of board works best for simple electronics

7. Double-Sided PCB Double-sided PCBs are much more common than single-sided boards. Both sides of the substrate have metal conductive layers, and parts are attached to both sides as well. Holes in the board allow circuits on one side to connect to circuits on the other side.

8. Multilayer PCB Multilayer PCBs expand on the technology used in double-sided boards. They have several layers of substrate boards, and insulating materials separate the individual layers. As with double-sided boards, components on multilayer boards can connect to each other through holes in the board.

9. What PCB is made of? A basic PCB starts with a copper-clad fiberglass material or thin copper sheets attached to either side of the board. It consists of :- 1. Copper Foil 2. Copper Plating 3. Solder Flow 4. Solder Mask 5. Trace 6. Slots and cut outs

10. PCB Base Base material of substrate is fiberglass FR-4 is used commonly Solid core gives PCB its rigidity and thickness There are also flexible PCBs built on high temperature plastic like Kapton

11. FR-4 Composite material composed of woven fiberglass cloth with an epoxy resin binder that is flame resistant FR stands for ‘ Flame retardant” Created from constituent materials- epoxy resin, woven glass fabric reinforcement, brominated flame retardant etc. in 1968 It employs Bromine to facilitate flame resistant properties

12. PCB characteristics Through-hole technology Surface-mount technology

13. Through-hole Technology The first PCBs used through-hole technology, mounting electronic components by leads inserted through holes on one side of the board and soldered onto copper traces on the other side. Boards may be Single-sided, with an un plated component side, or more compact double-sided boards, with components soldered on both sides

14. Through-hole Technology

15. Surface-mount Technology Surface-mount technology emerged in the 1960s, gained momentum in the early 1980s and became widely used by the mid-1990s. Components were mechanically redesigned to have small metal tabs or end caps that could be soldered directly onto the PCB surface, instead of wire leads to pass through holes

16. Surface-mount Technology

17. Tools used for PCB Schematic and Layout Design Express SCH Express PCB

18. Fabrication Following are the basic steps of PCB design. Set-Up Imaging Etching Drilling Masking Silk Screening Route Electrical Test

19. 1. Film Generation

20. 2. Shear Raw Material Industry standard 0.059" thick, copper clad, two sides

21. 3. Apply Image and Drill Holes Apply Photosensitive Material to develop selected areas from panel

22. 4. Strip and Etching •Remove dry film, then etch exposed copper •Tin protects the copper circuitry from being etched

23. 5. Solder Mask Apply solder mask area to entire board with the exception of solder pads

24. 6. Solder Coat Apply solder to pads

25. 7. Silkscreen Apply white letter marking using screen printing process

26. Photo contact PCB Art Work Film Maker PCB Art work film maker unit serves as negative making printer as well as illuminated art work table for circuit work, taping and inspection of Film and Negatives.

27. Double Sided U.V Exposure Unit The unit is a bench top Double Sided Exposure with a unique sandwich glass frame which gives excellent contact between artwork film and sensitized material for high resolution exposures.

28. PCB Shearing Machine It is a table top model with a horizontal blade. The blade is made of hardened metal to provide efficient cutting of PCB Laminates in paper and glass epoxy. A convenient handle in the centre allows easy cutting of the sheets.

29. Photo Etch- Etching Machine The developed PCB is etched with a 220 g/l solution of  ammonium peroxydisulfate , added to 1 liter of water and mix it until everything is dissolved. Theoretically it should be possible to etch slightly more than 60 grams of copper with 1 liter etching solution

30. PCB Drilling Machine  For drilling, tips are hard metal which are pointed for digging of perfect track. Drill machines vary from size to size and accordingly tips are arranged and fitted to it.  Small drilling machines  are perfectly used for drilling tracks for embedded circuits 

31. Photo Cure Baking & Curing Machine Ideal for baking and drying PCBs. Coated PCB has a capacity to handle PCBs of Size: 300x250 mm size at a time. A linear Thermostat temperature control 150’ C to 300’ C is provided.

32. Photo-Dye/ Developer This unit will develop the PCB and colour it after photo resist coated PCB is exposed. The system of two stainless steel tank one containing developer and other containing dye.

33. Roller Tinning Machine Completely remove photo resist or photosensitive lacquer from tracks and pellets from circuit using appropriate stripping agent. Provides effective protection against corrosion ensuring a long storage life.

34. Photo Resist Dip Coating The machine is a compact bench top used for coating of liquid Photo resist on PCB, aluminum panels for anodising or any job involving photo chemical milling

35. Printed Circuit Board

36. Thank you