A printed circuit board is a thin plate which has chips and other electronic components. A printed circuit board is used to support and connect electrically electronic components that use conductive pathways from copper sheets laminated onto a non-conductive substrate. A printed circuit is used in all simple commercially produced electronic devices. It is possible to make a printed circuit at home. Thanks to the great improvements in the processing and printing technologies, it is quite easy to make a high quality printed circuit at home.
Gather all the required items that will be used in the process of making a printed circuit at home. These items are.
- A PC with a laser printer like a hp laser jet
- Cloths iron
- PCB hand drill with 0.8mm and 1mm drill bits
- One liter glash jar that has a plastic screw top
- A copper clad fiber glass board
- Press n peel PCB transfer system
- Ferric chloride copper etching fluid 250ml
- PCB cleaning rubber
- PCB solvent cleaner
- Two different sized plastic etching trays
- Safety wear like glasses, overalls, latex gloves
First, transfer the circuit layout from the PC to the unique Press n peel film. This project provides laser printing files for printing the circuit layout direct onto the film. Cut the film into two halves for a small board that will last longer, put the half film in the laser printer in order the print can appear on the blue Matt side and at a DOS command prompt type, copy the filename so that it can print on the film. This procedure will produce a contact print with the black image as copper on the final PCB.
You can now transfer the artwork to the copper board by following the press n peel film instructions. Clean the copper board properly using the PCB cleaning rubber, let the iron heat up to 300 degrees, which should be the acrylic to polyester settings, hold the film with the print with contact to the copper and gently iron for about a minute until the film until the print appears black via the film and then allow the it to cool for about five minutes or you can use water to cool it down. After it has cooled, peel the film off. This should give a black clean print on the copper. If you overheat or move the film, then the writings and tracks will be smeared and the film may wrinkle. If you do not use heat evenly the film will fail to stick and it will not be dark enough. If this happens, clean the PCB and start the process again.
The PCB should be etched to remove the unwanted copper. To shorten the etching period, keep the etch chemical warm. Dilute the ferric chloride with water and pour in the one liter glass jar and screw it, place a newspaper sheet on some flat surface and put trays on it, fill a kettle with water and let it boil and then place the glass jar containing the ferric acid in a bucket of hot water and let it heat for some time.
Pour about an inch of boiling water into the tray at the bottom and place the tray on top, place the PCB copper side up on the top tray and pour the ferric chloride, rock the top tray gently to keep the etch fluid moving and be careful to avoid spillage, all the unwanted copper should disappear in about 15 minutes and finally, remove the board an place in a bucket of cold water for cleaning.
Put a soft block of wood under the PCB to provide a good base for drilling. Dry the board and clean the blue etch with PCB solvent cleaner, with the help of a PCB drill bit, drill out all component holes, make some 1mm holes for the connectors and 3mm for corner fixings and finally, use the PCB rubber to clean the copper for soldering. Your printed circuit is complete and you can soldering in components.
- Making a printed circuit requires ferric chloride which is explosive so it is important to have some protective clothing to avoid skin and eye contact with the explosive chemical.
- Use of protective overalls, gloves and glasses is highly recommended.
- If the chemical gets on your skin, wash it immediately with lots of water and soap.
- Ferric chloride can still remain in the clothes even after washing them.
- Read the instructions before using the etching chemicals.
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