There is a 3D desktop printer RepRap which can print most of its own components.
Assuming each printed printer will print the next one and so on. Are there any limitation how many times this can be achieved?
For example somebody printed for me printer and I do the same for my friends and they do the same for theirs. Can this go forever (since 3D model stays the same), or there are any serious side-effects/disadvantages of doing that continuously?
The files used to print these objects are digital, and do not degrade in any way after each printing. There are no side effects or degradation that occurs over time due simply to printing them multiple times.
This is the RepRap philosophy, and the machines are actually designed with enough tolerance for printing and building mistakes that even if the print isn't perfect, it will not only work fine, but it can print a printer better than it was printed, with some care and attention to calibration.
The process still takes a lot of human intervention, in the way of building the new printer and properly calibrating it. If there are errors in the printer or the prints it produces, they can almost always be attributed to the builder/calibrator/user, and not to the design or the fact it's the Nth generation of printer.
The reprap printers have often been compared to plants, providing fruits to you and the possibility to reproduce themselves.
This analogy holds in both good and bad ways. Any life form can reproduce itself only so often without artefacts (mutations) being introduced.
It takes a bit of skill to build, configure and run a reprap printer. While the parts can be passed on, that doesn't necessarily hold for gained experience. Chances are that the parts your printer produces are not as good as those that you have received to build the printer. At least not until you caught up on the learning curve.
A reprap has a lot other parts that are not printed and can vary in quality independently from the printed parts. It makes a difference what steel rods are used, what driver circuit for the motors, etc. If you give printed parts away that are as good as those that you received yourself, the added parts are not necessarily as good as your.
My recommendation would be that you and your friends get printer parts from that somebody and you build your printers together. While giving parts to others is a great thing, building 3D printers together with friends is greater.
As long as you maintain each printer and keep a proper calibration, go for it, this is what they were designed to do, I've even made replacement parts for myself.
Unfortunately the RepRap project just shut down on January 15th 2016 due to their lack of sales.
I have a reprap that came from a reprap, and has made another reprap.
Just make sure that when printing out the pieces for the next you are properly calibrated, otherwise the next machine might be built crooked;
Your only limitations will be the electronics pieces and the small amount of hardware that you will need to buy.
