[blackrock]

I wonder when we can start 3D printing our own resistors and transistors.

[ducktective]

I'm no expert in this field but I think the challenging part in IC design is the light-based lithography process that makes integrating large numbers of transistors possible...so I guess the 3d printing part is not the limiting factor.

[artemonster]

They already are. Most lithography processes are additive, including making the active components themselves (is some applications, not in general)

[djmips]

This might be of interest although quite an investment in both knowledge and equipment. Home built IC.

http://sam.zeloof.xyz/first-ic/

[bobsmooth]

You can do photo-lithography at home. Applied Science has a few videos on the subject.