[mdorazio]

Great question, and the answer is probably "it depends". I've got all of those except the robot arm/part picker and even if you had really expensive tools like metal sintering printers and a 5-axis CNC mill, you would still have to buy a lot of the components that are produced with specialized machinery. I'm going to go out on a limb and say that maybe in 20 years we'll be able to self-replicate machinery with raw materials inputs and a lot of work. It wouldn't be even close to economically viable to do so, but it might be possible.

It's important to remember that the majority of the core technology in 3D printing today actually dates back to the late 1980s. We're starting to see some interesting developments in materials and capabilities, but there are still plenty of limitations that need to be overcome.

[jacquesm]

I highly doubt your estimate is even in the ball(bearing) park.

Spindles, motors, circuit boards with components on them and bearings, slides and so on are all multi material or very complex processes usually only doable if you produce a lot of something in one go.

Just try to think about what it would take to print something as trivial as lacquered copper wire for stepper motor windings or a circuit board with a reasonable level of integration.

And the biggest issue with that prediction is that there is no gain from it: printing the non-commodity parts is the whole trick to efficient 3D printing, mass produced parts will have incredible accuracy and very low pricing so use them when you can and 3D print the remainder.

[mdorazio]

I don't think you're arguing against what I actually said. I said in 20 years it might be possible to replicate a printer using nothing but raw materials and a lot of work, but it wouldn't make sense economically. That's very different than saying you'll be able to print all the parts you need in one go, or that you would want to, which obviously isn't viable without molecular-level assembly. That's a holy grail in the distant future. But making PCBs is already possible without specialized equipment, metal sintering gets you pretty far on components needed for things like steppers and threaded rods, etc. If you follow the research being done (ex. [1,2]) it's pretty clear that the boundaries of what's currently possible are being pushed in interesting directions.

To me the biggest hurdle is the electronics, which currently do require special tooling to even produce basic components. You're probably right that we're more than 20 years from self-replication ability (again, not practicality), but I'd be surprised if it's more than 50 years out.

[1] https://arc.aiaa.org/doi/abs/10.2514/1.A33409 [2] https://3dprintingindustry.com/research/