PCB Production
I have produced my own PCB's at home for many years, starting with the ubiquitous Dencon Dalo etch resist pens. They work, but you can hardly call them neat. I have also used rubdown etch resist transfers especially pre-formed 0.1" IC pads. When I first started making PCB's CAD type applications simply did not exist, and when they did arrive they were custom machines with a custom price tag. Things have changed now, and there are several PCB design systems available, many commercial systems have reduced / lite versions of their products for hobby users. There is one Open-Source package available as well. This is the one that I use, it's called Kicad.
If you had ever used products such as Eagle, then you will be in for a rather nasty shock. Kicad works in a different way, and you have to change the way you think to make things happen.
Software such as Eagle use a system that is essentially one device maps to one footprint.
So if you have a resistor, you might have a file for every value you use, and every size.
In Kicad the process is different, you have a generic device which can be set to any value and any number of footprints. So a resistor of 100 ohms could be set to a 1/6 watt device, 1 watt, a 50W metal clad and so on. This method means that you only need the generic device, and then a set of footprints. The issue is that you have to set the association up yourself.
It's very easy to do, but it's surprising just how many people have problems. It's just a bit of a culture shock.
All the PCB design tools output the final result as some form of file, the standard is a Gerber file, which can be sent to the various PCB production companies to manufacture your board. Many people do this, and the costs are fairly reasonable. This allows you to design boards with multiple layers and plated through holes. For the hobbyist user, this is used to be an expensive option. However there are now a number of Chinese PCB houses that will produce multi layer boards of a small size for just a few pounds.
I still make my own boards, and the PCB design tools will also allow the production of the necessary artwork that will enable you to produce the PCB's yourself. Obviously you will be limited to single or double sided boards and no plated through holes.
The next stage of the process is to transfer the design from the artwork onto a copper clad board. This can be done in several ways, and I have tried several of them. Laser printer toner is basically a plastic which is melted into the paper. Some people use heat to transfer toner from a printed page to the copper board. There are even specialist papers that will allow the toner to be transferred easily and then the paper will "lift off" when soaked in water. I have had some success with this method, but in the end I decided that a photographic method would be better.
Just like a normal photograph, a light sensitive layer is coated onto a copper board, exposed and developed. The resultant image is resistant to the etching process and the board can be etched in the normal way. Photo sensitive boards are available ready coated, and they are fairly cheap. They also produce the best quality results. The only drawback is that the pre-coated boards do have a limited stated shelf life, and if you do not make many boards this can be a slight problem. In practice the shelf life is longer than stated, (way longer in fact, I've used boards that are several years outside their "use-by" date, and they still work fine, however there is some risk. Another option is to use a spray or liquid resist and coat the boards as you require them. A product called the SENO applicator system is now available, this is attractive as the process is contained within self sealing applicator bottles which have a shelf life of two years. I decided to try this system out, and the results have been very good.
The biggest problem I encountered was that there is very little in the way of instructions for using the SENO applicator system, so I have had to do a lot of trial and error testing to find out the best way to use this product.
