MAKING A PCB
Making PCB's will help very much in robotics. They can be used as the body for smaller robots. Making ur own PCB's give the advantage of making the most efficient design and size. But it is a painful process. In such cases a general purpose board can be used.
TOOLS REQUIRED
1. A phenolic laminate board)
2. Ferric chloride (in powder form)
3. Enamel-paint/ alcohol based marker/Nail Polish
4. Set of very fine brushes (0-3 sizes)
5. Petrol, spirit or Acetone (Nail polish remover)
6. Hacksaw File and Drill with various bit sizes (1-5 mm).
7. Varnish
8. Steel wool
PROCEDURE
1. The board surface is cleaned with petrol, spirit or any other cleaning agent. Scrubbing with a steel wool can also help.
2. The shape and size into which the board is to be cut is marked. Mounting holes are drilled and the boards are cut.
3. Draw the layout or photocopy the design. Don’t forget to invert IC pins.
4. Two coats of paint are applied and let to dry for at least three hours.
5. Suitable holes of desired sizes are drilled for inserting components.
6. Hot water (85 degrees) is taken in a flat bottom plastic tray.
7. Then 30-50gms of ferric chloride is added to it.
8. The board with the copper side facing up is fully immersed in the solution.
9. Few drops of hydrochloric acid are added to speed up the process.
10. The etching process takes about 30-60 minutes to complete depending on the size of the PCB. The backside of the board should be clearly visible, if not then it should be etched for few more minutes.
11. After the etching is complete, the board is cleaned under running water and then paint is removed using acetone or spirit.
12. Rough surface around the holes is scrubbed.
13. Components are soldered
14. A coat of varnish is applied to prevent oxidation.
Precautions
1. Ferric chloride is a very harmful chemical. It is hygroscopic in nature (it absorbs moisture from air) so it should be kept in airtight container all the time. Gloves should be used to handle it. It should not be let to be in contact with metal because it eats away the metal.
2. Etching of boards should be done in a well-ventilated area, as the fumes produced are extremely poisonous
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