Is there a minimum axis speed to achieve decent quality prints?

I've been working on a little 3 axis Cartesian robot using threaded rod as leadscrews with custom made leadscrew nuts. So far this seems to be working great, there's very little backlash (in fact so little to be unnoticeable so far), the leadscrews turn very easily and my motors have no problem turning them, and so far it's working well milling PCBs and aluminium.

Now I would like to make this truly multi function. I'm already working on attachments so it can be used as a lathe and I definitely would also like it to be able to print.I read on the Wolfstrap wiki page that the speed of the axis was too slow at times so is there a recommend or rule of thumb minimum to achieve decent prints?

Also in the long run I would like to make my machine "self replicating" and make the designs/schematics available FOSS style. Is there already a name for replicating rapid production and milling machines?

Sorry if this has already been answered but the search didn't bring up anything.

In theory I don't see why there should be a minimum speed that will work, you're extruder will be emitting plastic at a very low rate but it should work ok.

However, you will be waiting a _very_ long time for prints to complete if all three axes are moving slowly. I start to have problems on the z axis of my Prusa i3 if I try anything more than about 5 mm/s. If all three axes are moving at this speed it'll print at a snail's pace. I print the x/y axis between 30 and 60mm/s depending on patience and quality, and do non printing moves at 100mm/s. If you're running an order of magnitude slower than this it'll turn 2 hour prints into a full day... I'm not that patient