I am looking for a machine for PCB fabrication.
Can you help me understanding the type of machines available on the market for a hobbyst use?
When i was at school (technical school) we had a complex chemical system, in which the design had to be printed on a transparent sheet, and then with a UV lamp it was used to burn a photo-resist layer; then with the caustic soda the burned part was removed, and an acid solution was used to remove the uncovered copper. It was very bulky and involved the use of hazardous liquids (for what i know).
There is also a way to do that at home, using laser printers and ironing the design directly on the copper layer, and then removing it with some acid, again. But AFAIK this method is not very accurate.
I've seen also a CNC (as other described) machine (of the size of a microwave oven) that use cutters to directly remove the copper layer and that works on gerber files (generated by the CAD software). It takes about an hour, depending by the complexity of the design, and i think it could cost some hundreds bucks.
All these machines can only create single layer (at most dual face) circuits. For more complicated things (multi-layer PCB) you need to refer to a specialized company.
As ceconel (omg cross-reference XD) mentioned, the price for manufacturers scales very badly for small numbers; could be that 1 piece costs you only a bit less than 50...and it's due to the fact that they use masks that are the most expensive part of the process...
For the milling process, there's http://www.colinbus.com/en/pcbprototyper.html
As clabacchio noted, you can't have multi-layer, only dual face. Given the price and the limitations (consider also that it won't produce plated holes, solder mask, etc.) you really need a high volume demand to do it yourself instead of using a PCB fab service. It's quite easy to find providers to do a batch for around $100 with a 2-week lead time.
I myself use photosensitive or thermal transfer for simple, single-side boards - when in first prototype stage - and send the more complex ones and the final versions to a fab service. I searched for machines like you but came to the conclusion that for my volume requirements it's not economically efficient. So consider it carefully. There may be less expensive options than that I mentioned, but they'll have less precision too, and in this case it's not better than photo/thermal methods. I can get good results with photosensitive boards if the vias are 0.5 mm or more; 1 mm for thermal transfer.