This is a project I finished a long time ago and even though I no longer use it the idea could be useful for someone else into home made PCB's.
Over the first few years of mucking around with electronics I tried many methods of making PCB's at home. Starting with hand drawing the tracks with a marker pen, then moving to some of the iron on methods. Finlay I decided the best (most accurate, repeatable, satisfying) method was the UV sensitive system from Kinsten.
Over the first few years of mucking around with electronics I tried many methods of making PCB's at home. Starting with hand drawing the tracks with a marker pen, then moving to some of the iron on methods. Finlay I decided the best (most accurate, repeatable, satisfying) method was the UV sensitive system from Kinsten.
To make this system work as well as possible the exposure should be done on a flat bed with the artwork sandwiched between the PCB and light source. Kinsten sell a nice UV exposure unit (picture below), but it is a bit pricey for the home user.
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| Kinsten Exposure Unit |
As an alternative I salvaged an old flat bed scanner from a local throw-out. Removing the workings of the scanner I placed 5 small UV fluorescent tubes and associated power circuits that I removed from a number of 'party' lights that were designed to run from batteries or a 9v plug pack. I seem to remember paying around $5 each for the lights on sale. To finish off the project I added a switch mode power supply (240v -> 9v) and a timer from an old oven (rotate to set, rings a bell and switches off when finished).-
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| Photos of the recycled flat bed scanner |
This unit gave me the most repeatable and accurate home made boards, I was able to produce small pitch footprints for SMD and make double sided boards (without plated through holes \ vias). There are also chemicals available to 'silver' the exposed copper (at room temp) to give the look of tin platting (HALT) as can be seen in the example below.
In the end I have decided to get a commercial company to make all of my PCB's now. Once you are handling small SMD parts and want high density there are too many defects when trying to make your own boards economically. I recommend the following PCB manufactures:
- Futurlec [Thailand: For Through Hole and Larger SMD - Double Sided]
- PCB Core [China: For High Density, Low Pitch SMD, Multi Layer]
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| Example PBC made using this system |
Of course, its is pretty hard to come by a stand alone scanner these days, they all seem to be built into multifunction printers!
