Welcome to the wonderful world of quality control :)
Making something is easy, making something with a high repeat accuracy and very low fail percentage is super hard.
I learned this the hard way myself with an IO expander for the Atari ST that I designed. I needed it to drive the lathe/mill controller, the ST simply had too little IO capacity so with a bunch of decoders and latches I was able to drive a much larger number of motors and relays.
The first one worked like a charm. So did the second and the third. But the fourth, we couldn't get it to work no matter what. Part variability led to some signal arriving just that much earlier causing the latches to remember data that was still stale. The reason was - in retrospect - quite simple, the design had assumed that the input to the latches had long stabilized before the latch pulse was sent. But because on the ST the latch pulse took a different route as well there could occur a tricky situation where the output of the buffer driving the data bus on the far side would still be rising. To make things worse, this would not happen repeatably, only with certain patterns of 1's and 0's. In the end, a single buffer in line with the latch pulse caused enough delay to stabilize the input to the latches and that solved the problem.
(Of course not with every board...).
Anyway, that was electronics, this is mechanics but the same principles apply.
Something funny is happening in youtube land, classical music.
There are a whole pile of 'youtube wonders' that can play an enormous variety of material but that have never in their lives done a live concert. It took a long time before one of those miracle people owed up to the recipe: record hundreds, or even thousands of times. Pick the best.
That's the difference between an actual pianist and youtube miracle workers: a pianist can do what they do repeatably, youtube miracle workers would end up being booed out of actual performances.
Repeat accuracy is very hard, mechanics, electronics, playing the piano, the subject hardly matters.
I've been reading all kinds of books and articles about quality control last year and I believe that in a mature market it is the only absolutely critical element in any production process. If all your competitors are doing good QC and you don't you're dead. Everything else can be fixed but without repeat accuracy you'll be fighting a lost battle.
Another way to look at this is that for real world stuff where there is a whole company dependent on the output of the 3D printer the cheap one is too expensive, and the expensive one probably is cheap.
That's because if you were allowed to make a million parts with each and you could take the best part from each set of parts they'd be very close. The 'best' part of those two might even be from the crappy machine. But if you needed just 50000 parts that would simply work your cheap printer (or even a small army of them) would wear out long before completing the order, and that's what makes them expensive.
Partly this was an illusion created by the combination of affordable
video equipment and the Internet; young jugglers now kept their
cameras running all the time, so if they hit a trick one time out of
100, they could upload the proof and make themselves look like gods,
even if they’d never be able to execute the trick onstage, like
Gatto could.
when I teach innovation classes we talk about the difference in mindset between making 1, making 10, and making 100 of something (and obviously this would scale to 1000+ but that is kind of beyond a lot of students). Until you have experiences with scaling manufacturing you have no clue.
I used to do consulting work on this (my background is in manufacturing). Typically I would come into a company at the prototype stage and work with them to redesign the prototype to make it manufacturable...I loved doing it but wow does that mindset have to change about what can be accomplished. There was an article on HN a while back about why you can't manufacture like Apple that I really should have saved, it makes this point beautifully.
This is a key component in why hardware start-ups are hard. Proof of concept: dead easy, as long as physics does not make your product impossible. Prototype: a little harder. 0-series: already quite hard (that's roughly what the story above was about). Mass manufacturing: super hard.
It's also why manufacturing samples should never be taken as indicative of what a plant will actually put out and you still need to sample the actual product to determine if quality is acceptable or not.
Lots of companies doing business with third world producers have found this out the hard way. (And then there is malicious substitution as well to content with.)
And requires skill sets that seem really similar but are not actually all that similar. They are linked through engineering design but yeah...they aren't.
Making something is easy, making something with a high repeat accuracy and very low fail percentage is super hard.
I learned this the hard way myself with an IO expander for the Atari ST that I designed. I needed it to drive the lathe/mill controller, the ST simply had too little IO capacity so with a bunch of decoders and latches I was able to drive a much larger number of motors and relays.
The first one worked like a charm. So did the second and the third. But the fourth, we couldn't get it to work no matter what. Part variability led to some signal arriving just that much earlier causing the latches to remember data that was still stale. The reason was - in retrospect - quite simple, the design had assumed that the input to the latches had long stabilized before the latch pulse was sent. But because on the ST the latch pulse took a different route as well there could occur a tricky situation where the output of the buffer driving the data bus on the far side would still be rising. To make things worse, this would not happen repeatably, only with certain patterns of 1's and 0's. In the end, a single buffer in line with the latch pulse caused enough delay to stabilize the input to the latches and that solved the problem.
(Of course not with every board...).
Anyway, that was electronics, this is mechanics but the same principles apply.
Something funny is happening in youtube land, classical music.
There are a whole pile of 'youtube wonders' that can play an enormous variety of material but that have never in their lives done a live concert. It took a long time before one of those miracle people owed up to the recipe: record hundreds, or even thousands of times. Pick the best.
That's the difference between an actual pianist and youtube miracle workers: a pianist can do what they do repeatably, youtube miracle workers would end up being booed out of actual performances.
Repeat accuracy is very hard, mechanics, electronics, playing the piano, the subject hardly matters.
I've been reading all kinds of books and articles about quality control last year and I believe that in a mature market it is the only absolutely critical element in any production process. If all your competitors are doing good QC and you don't you're dead. Everything else can be fixed but without repeat accuracy you'll be fighting a lost battle.
Another way to look at this is that for real world stuff where there is a whole company dependent on the output of the 3D printer the cheap one is too expensive, and the expensive one probably is cheap.
That's because if you were allowed to make a million parts with each and you could take the best part from each set of parts they'd be very close. The 'best' part of those two might even be from the crappy machine. But if you needed just 50000 parts that would simply work your cheap printer (or even a small army of them) would wear out long before completing the order, and that's what makes them expensive.