Micro-stepping controller chips.
Before that, the precision available without gearing and feedback wasn't sufficient. There were systems but they were order of magnitude more complicated and several orders more expensive.
Before that, the precision available without gearing and feedback wasn't sufficient. There were systems but they were order of magnitude more complicated and several orders more expensive.
You can look at early calibration settings descriptions and they're still talking about e.g. "The number of X stepper-motor steps needed to move 1 mm for the PIC."
hard drives use voice coils, a completely different technology. The circuitry that does that evolved and certainly influenced the creation of microstepper controllers: the neat trick they do is treat the stepper motor as a voice coil in between full steps.
Hell, CNC machines existed back then too.
The patents, compute, research access, and dozens of other relatively small barriers created a thicket of challenges and no obvious way to reconcile them, even if you had all the right ideas and inspiration. I think the internet would have been needed in order for all those ideas to come together in the right way.
I mean, towards the end of the decade was something like the ImageWriter, which let you do bitmapped graphics, as a row of 9 dots at a time. At https://www.folklore.org/Thunderscan.html?sort=date you can read about the difficulties of turning it into a scanner. (Like, 'We could almost double the speed if we scanned in both directions, but it was hard to get the adjacent scan lines that were scanned in opposite directions to line up properly.')
The LaserWriter wasn't until 1985 or so. My first hard drive, 30 MB, was a present from my parents around 1987.
By the 1996, laser-based 3D printing based on cutting out layers of paper was a thing, available for general use in one of the computing labs in the university building where I worked.
The result smelled like burnt wood.
When I visited a few years later they had switched to some other technology, and one which could be colored, but I forgot what.
The motors tend to fall to the nearest full step when loaded hard. Most people I have discussed this with believe there is little resolution gain (if any) past 4x microstepping but it certainly is a lot quieter to use x256.