Filed under: Making PCB's
Making the PCB’s
The PCB layouts from art worker are printed out onto assertate using a laser printer, the black image will end up as copper on the final PCB. The print should be of a mirror image of the circuit, as this will ensure the black areas of the artwork will be in contact to the PCB’s Photoresist during UV exposure.
The board is cut to size using a guillotine, this is then cleaned... The layout is then printed onto the board using the UV exposure unit. The exposure unit has a timer on it, it is important that this is set to the right time, in this case two minutes. Once complete, the printed boards are washed of using photoresist universal developer. This is done by placing the crystals into a tray and mixing them with warm water, the boards are then put into this and the solution washes away any particles. The layout of the PCB’s should become clearer and after one or two minutes they can then be washed of using water.The next process involves using Ferric Chloride, when using this safety gloves, classes and overalls must be worn. The PCB’s are place in the lid/mesh basket board holder of the developing tank. The Ferric chloride used in the tank must be kept warm at 45 degree C this is because it reduces the etch time from around 1 hour to 15 minutes. After several minutes, the copper will start to fall off, leaving the circuitry. Once complete the boards can then be washed, remembering to wear all the safety gear. Using a precision high speed drill and a 1mm bit the holes can then be drilled into the circuit.
