The RepRap project sorta hit some of your points. It was more about establishing and spreading 3D printers. Evangelizing them. One printer would print all the plastic parts for to make another 3d printer. This could then be given away or sold. Things like screws, rods, motors, and controllers were “vitamins” that need to be added to make the printer. Obviously people were doing the assembly not the printers. They also violated your rule #5 because they could do tasks besides replicating.

My second printer was a Prusa MK3S+. It’s heritage came out of RepRap and a lot of its parts were 3d printed.

I print FDM. I’ve paid for the printers and make a little money each month. Not enough to live on but enough to finance the hobby.

My mom hooked me up with a teacher who wanted a watercolor insert for altoid tins. The lady was enthusiastic and would pay me every year to make them for all her classes. The design she pointed me to was a BSD license but I remade it anyway. I’d make like 100 prints at $5 each. Made like $500 X 4 years.

I haven’t heard from her for two years. I don’t know if she still teaching or found another printer.

I make some photographay related devices and give them away on printables/thingverse. For the most popular designs I mention that they are for sale on etsy. I know there are a lot of people interested in the things but without a 3d printer. I’m also not shy on mentioning my designs on social media if they are a solution to that person’s photographic problem. On etsy I don’t mention thingiverse/printables except for one disability related item. The etsy sales are about $120 a month.

Go for the used Prusa MK3S+. People used to pay a premium for assembled and tested printers. As long as you can get the printer to you without being banged up in shipping it’s good. Really shipping would be my biggest concern.

I have a MK3S+ and it just prints. I print for my Etsy shop and don’t really feel the need for a backup printer. I have 1600+ hours of printing on it. In that time I’ve had one nozzle clog and one blob. I do a little dust filter on the filament so i don’t often get clogs https://www.printables.com/@Fohn23_807562/collections/641537

I’m totally happy with just the smooth sheet. The textured sheet is supposed to work better printing PETG but I’ve been able to get perfect PETG prints on the smooth sheet using windex as a release agent.

Depends on how you define purple. If violet is close enough to purple for you then that “purple” would be a single spectral color, a single or continuous set of wavelengths. If it’s just a little more like magenta it would be a non-spectral color. A combo of red and blue light.

Plenty of non-spectral colors. Most things we see are non-spectral colors. Single pigments give off multiple wavelengths. Most things have combos of pigments on top of that. Emission spectra are multiple wavelengths.

My daughter has it. It makes the cars touchscreen a customized extension of the apps interface. So maps or whatever is running on the car’s screen. Some of the controls on the side of the screen also interact with the phone. It’s more integrated than a bluetooth connection.

Sure. That’s OK with me.

Prusa Mk3S+ with something like 1600 hours and a new orange pi octoprint server.

Next year I may get a MK4 or a X1 Carbon

For PLA I set set it as prusiment in my slicer and forget it. That’s hot enough to do silks and fancy filaments. It’s hot enough to have good layer adhesion.

For octoprints I print the first layer at 215°C to help with adhesion then turn it down to 205°C to avoid stringing.

Special non-pla filaments I do what’s suggested.

Eryone has been doing this since at least last year.

I got an 1 gig Orange pi zero 2 with a 2 port USB expansion board. I got it from ali express with a 32gigabyte micro SD card, USB to USBC charging cable for like $40.

I 3d printed a case for it. Provisioned it with a heatsink, fan, 18W USB power supply, and a UPS.

I use it as an octoprint server, the extra USB ports go to a webcam and a fan if i feel like it. It’s been reliable but I’ve only had it a month. Transferring jobs is nearly instant plugged into gigabit ethernet. Transfer is via API key not web interface. Seems to do alright in the CPU department. It has to parse some of the larger jobs for a minute.

Prints perfectly. Only had one resent packet USB packet so far. After it prints rendering out 1080P time-lapses was slow. It would hit like 70% cpu usage and take hours. Rendering out 1080P octolapses with fewer frames and less movement would hit 98% cpu use but be done very fast - like 10 min.

They just announced an orange pi zero 3 with a similar form factor (but not exactly the same) and larger faster memory.