Ask HN: Why did consumer 3D printing take so long to be invented?

Ya I've updated the title to consumer to be clearer

I don't know that I'd argue that "consumer" 3D printing, as in a printer at home that just churns out a part when you want it, is even really hear yet, certainly not in the way that a dishwasher or lawnmower is. You need to do your own slicing, thinking through supports and brims and layer height, and the printers themselves need no small amount of troubleshooting that is much more than "turn it on and off again". So, I'd argue it's still a hobbyist realm than a consumer one.

You don't have to have a large market in order to have a profitable business. That said, the market for 3D printers at home is larger than many assume, especially as printers get closer to being simple one-button-push kinds of things.

They will probably never be the sort of thing that exists in every home, but they could very well be the sort of thing that exists in every home workshop.

What needs would home 3D printing fill in the 70s?

A complete set of woodworking or metalworking tools was a lot cheaper than a home computer. And there were entire magazines dedicated to proliferating free or easily obtained schematics/designs. Labor was also cheaper, and people had more time for hobbies.

I would also argue the point that it would have been relatively cheap. We are used to the ubiquity of cheap DC motors and precision parts being a click away. But if you were to rummage through a vintage Radio Shack to cobble together a home printer, I think you would struggle to construct anything precise enough with consumer available parts.

> a melting plastic

Don't sleep on the chemistry of filament. It has to be extremely precise and consistent. We benefit from the massive economies of scale today, but this was small batch stuff 20-30 years ago. And if we are talking about the 1970s the plastics were really primitive by today's standards.

It's also easy to underestimate how much computation is involved and how little there was in the 70s. The 3D printer slicers generally require several seconds on modern hardware to calculate their final path. The resulting files are in the several megabytes. My Bambu 3D printer is all but festooned with sensors and is constantly adjusting things, but even the simple ones have more to their firmware than meets the eye. Even assuming that they'd use some simpler algorithms and data structures, you're looking at vast computation times, and most likely, vastly simpler objects being printed.

Even something that seems as simple as "sous vide" cooking, which is basically a heater hooked to a thermocouple, took a lot of little innovations to make practical to hand to the masses.

And then, there's the general improvement in motors speed, precision, and cost, along with any number of advancements here and there and everywhere to make it practical.

Could someone thrust back to the 1970s and given a fairly substantial budget make some kind of 3D printer? Probably. But it's slow, extremely expensive, and can print various sizes of plastic bricks and spheres and other very algorithmically simple objects, and in rather low quality without many, many years further development. I can think of many ways of bodging on various improvements, but they're all going to have their own compromises, not be garden paths to what we now think of as modern 3D printing. (For example, someone could bodge together a machine that offsets a rod on the printer head, and then in the offset space, has an object to be "copied", by basically banging into the object with a very crude sensor, so there's no generation of geometry at all. But this is going to be clumsy, inaccurate, and full of very complex and disheartening limitations.) You're not going to be printing Dwayne "The Rock" Johnson's face embedded into a toilet [1] or anything, at 1MB of geometry. It will be commercially useless and inaccessible to hobbyists.

[1]: https://www.thingiverse.com/thing:6436138/files