Hi, we have a PCB milling machine that accept Gerber files for top and bottom and produce PCBs with un-plated via holes on which we normally run and single core wire and solder both sides. The machine can make traces 0.25 mm wide.
There can be some prototype designs having BGA and QFN device packages, any suggestion how to do such prototyping in cheap way. The packages I am mentioning here are 16 pin as an example.
Do we have sockets or breakout cards avalible for BGA and QFNs ?
0.25 mm might be on the edge for a QFN(-16) package, considering the tolerances. Of course there are QFN sockets available, but they are pricy [1]. There are also break out boards available, at least for QFN packages [2]. What's the pin count and pitch of the BGA you are considering? As @KlausST recommended, there are several PCB manufacturers which are providing good prototyping quality at low prices e.g. smart-prototyping or JLCPCB (I made good experiences with both).